14 Sep 2005

The shit misses the fan

Steve from N.Ireland writes:

I'm considering installing a positivive input ventilation system like Nuaire’s Drimaster 2000? Any feedback?


Mark reckons:

Of all the varieties of ventilation systems you can fix into a building, this one has to be the worst.

Despite the rumours, positive input ventilation (PIV) like Nuaire's Drimaster (diagram above) probably won't be overlooked by the revised Part F of the E&W building regs, if only because there are a number of cases where it has been shown to work well. Usually these are on social housing schemes with condensation problems.

However, a new(ish) well-insulated house really shouldn't suffer from condensation problems. At normal relative humidity levels, the dew point is down at around 12°C and condensation won't occur at temps above this. So in this respect, it's answering a non-existent problem.

The only place where the temperature may fall below 12°C is within the roof or the external walls, so it's a good building principle to not encourage internal, moist air into these spaces. Which is exactly what PIV does.

The other major quibble with these single outlet fans (and this goes for the negative pressure fans as well) is that with just one inlet/outlet point, there is ridiculously little control over just where the air is blown or drawn from. Although the diagrams show the air gently wafting all through the house, in reality it's going to take the path of least resistance, which may be straight to or from the nearest trickle vent or badly-fitted window. The larger the house, the worse this effect will be: expect 90% of the house to remain completely unventilated.

Just compare this crude device with the heater/cooler in your car where you frequently have up to six outlets, some of them directional. I think the standard set-up of trickle vents and the odd extractor fan is preferable: they give you more control and are much more adaptable.

100 comments:

  1. Hmmm. I am a bit disappointed by that review.

    I live in a top floor housing association flat in Edinburgh and have a very bad condensation problem. The build is listed, with sash windows, single glazed that stream like niagra falls in winter. Its a stone tenement wihout insulation and mostly plasterboard clad inner walls.

    Over the past few years extreme mould growth has covered a lot of the inside of 2 outer walls in the bedroom and its impossible to place furniture or store clothes in that room (mould). When left unheated the room temp drops to 8 degrees C in winter. Any heating makes little difference and its as if any condensation in the house goes straight to that room and the walls and window. (I avoid using it in winter as much as possible.)

    In addition, due to local geography the building gets no sun in the winter months as it fails to rise above the ECA art college built on a hill behind the tenement. And in summer the walls are in shade for the same reason so are always the coldest part of the house.

    I just had a nuair surveyor in the house and its been proposed to install a nuair piv system. Type and location to be specified in the near future. Possibly in the loft.

    This is the only bad review of the unit I have googled online, others seem to be more positive.

    Has anyone any further feedback as to the pro's and cons of fitting one of these things in the above circumstances?

    What are the 'other' options?

    PS. I am really annoyed that the listed status of this build was never indicated to me when I took it on, as it will limit the scope of solutions available to make this place more habitable!

    I understand that mould is now classed a 'statutory nuisance' and a buliding suffering from it can be declared 'unfit for habitation.' I called my local environmental health dept at Edinburgh City Council and they said they rarely take any action in this vein because they see condensation problems as arising from the householders 'usage' as a matter of policy. If anyone wants to comment on that too I'd be interested to hear...

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  2. I am thinking of having a nuair unit for the same reasons, did you go ahead? Has it worked?

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  3. i am considering having a nuaire drimaster 2000 system put in the loft as i have severe condensation problems in my house but i am not sure whether its worth the money. also i dont want to pay huge maintenance fees in the future. if anyone has any ideas please let me know. i really am unsure. should i just get a normal extractor fan put in or this?

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  4. Hmmm I too am very disappointed with Mark's review. I cannot help but think this is a case of a review by someone who has "a little knowledge" about a product. More self opinion! I have practical experience of these systems for many years and boy they do work and are very very good. Most of the time the condensation problems are caused by older properties and the life style of the occupants, but even new builds are fitting them. Every person who I know who has them, all rave about the elimination of condensation. They have six settings for the extremes etc. I'm a property surveyor so am independant.

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    1. hi had one fitted a week ago no wet windows then this morning just bell half was wet any ideas I live in a 2 bed terraced house end terraced

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  5. Mark Brinkley seems to have very little basis or evidence for his comments. He talks about newish houses what relevance is this if you have an older house or one which is not so well designed.
    I have had Nuaire Drimaster units for over 20 years. They got rid of 90% of my condensation problems, the improvement in air quality was noticeable, and the house felt warmer at lower temperatures. The running costs were small and more than compensated for by lower house temperatures and decorating costs.

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  6. These nuair systems have been fitted to over 200 properties belonging to a housing association. They are causing problems with smoke detectors and making homes too cold. In my own home the unit is within 1 metre of a wall on three sides and sends draughts down the walls. We now have to sleep with the bedroom doors shut. In the eveing the cold in the hall way is ridiculous and we have to close all the downstairs doors to get any heat from our radiators. It is like living with the front door or a window open. I have mould in my bathroom - which i have not had in the 10 years previously and the condensation never clears from that room and it is next to the air vent. The cold air comes from the vent down the wall and down the stairs to the front door. It is a useless piece of equipment. Our tenant panel are campagining to have them removed as they consulted the fire brigade and they suggested that a hole into the loft is the equivilent of a window being open and so would feed a fire. I personally feel these are dangerous and do are not a solution to a damp problem. The solution to condensation damp is good extraction over a cooker and in a bathroom. Any major damp issues should be addressed properly and not covered over with something like this. If you don't have one, I urge you not to get one.

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  7. well sounds to me like this was installed wrong....
    1.Smoke detectors- the manual clearly states this and says they should be 1m away to ensure no problems.
    2.less than 1m to walls- yet again the manual states that it should not be positioned closer than 1m to any wall otherwise drafts will occur, obviously this isnt always possible so you can block of a maximum of 2 sides of the vent.
    3. It also sounds like the unit may be set up wrong, there is various speed settings which are altered for the size of the house, also the heat recovery system can be altered when setup right the system should make the house feel warmer using the redundant heat from the loft.
    4. I personally would still install a bathroom and kitchen extractor.

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  8. What a joke of a review! I have suffered from terrible condensation and mould for years - performing an annual 'disinfect and scrub' routine on my walls. The installation of the PIV (Drimaster 2000) solved all of this. I would recommend it to anyone.

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  9. I have just re discovered how brilliant this unit is, after 5 years the power supply to the unit has failed, and suddenly every window in my house is streaming with condensation. I will be getting it fixed as soon as possible.

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  10. I have had a drimaster fitted in the loft for two years now and it has cured the dampness and streaming windows almost immediately and I am well pleased. The only down side has been the cool air in the hall where the vent is fitted. However I have overcome this by setting a timer to the switch so that it only operates through the night from 11pm until 7am.
    This works very well for me and I wouldn't like to be without it.

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  11. AnonymousJuly 13, 2011

    Ive been looking at the drimaster 365 to fit in a home renovation project.
    I wanted to minimise background vent size and increase control over air change rates(regs req 30'000mm2 of vent for house)
    My main concern is air quality and not ness condensation issues.

    This unit appears to be a good solution without the expense of MVHR (heat recovery) system.
    I will be fitting a 30 l/m extract over hob (gas regs) and 15 l/m in bathrooms but when they run the air will be replaced from the loft and not direct from outside.

    should think Ill also consider balancing passive vents for even air distribution through the house and link unit to mains fire alarms.

    (Fire dampers are also available to close duct in event of fire)

    It makes sense to me???

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  12. Its a fantastic unit, I have fitted many of these units and I have learned exactly how they work, I have one in my house,they are great for existing houses with condensations problems, however in a new installation I would install a heat recover unit. Steve G from Llanelli in South Wales

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  13. These units simply do not work without heaters fitted, I know of manufacturers that try and sell these without the heaters fitted as well, but this will only go to make things worse for the occupant, and could also answer some of the complaints that I am readin on this blogsite.

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  14. I am about to get 1 of these units installed in my home but am in 2 minds can someone advise me the best thing to do as the damp is just on 1 wall.

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  15. a comment was posted on march 7th,whereby the chap put his drimaster on a timer,so that it only operated at night.
    my concern with this would be that during the day,warm air would rise from the living area into the unit in the attic creating both moisture in the unit and in the roof space.
    am curiou to know your thoughts.

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  16. Confused. Living in bungalow. Problem with condensation. Should we have the Nuair 2000 or should we have something like the Kair heat recovery unit, So much to take in.

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  17. It's interesting to note that this post has collected a large number of comments in the seven years since it was published (because it's on page one of a google) which seem to be either highly positive or extremely negative. My initial comments were really aimed at newbuilds which is perhaps unfair on Drimaster because the product is normally installed in older properties.

    It's all getting a bit like Trip Advisor for ventilation systems. And like Trip Advisor, it's none to clear whether this product is Triple A or junk.

    My original post was written from a theoretical point of view — I don't like the idea of putting a house under positive air pressure (i.e. so warm most air 'looks' for an exit route, rather than being drawn out by extract fans). I have no personal or professional experience of Nuaire's Drimaster, and I have nothing against Nuaire. I am not grinding an axe here and I'm happy to concede that many people are delighted with it, and a few are not, and I sincerely hope that commentators are not "talking their book." There's no way of knowing, especially when people sign is as Anon.

    With that in mind, I think the comments are fascinating although they really wouldn't help me deciding what to do. But if I lived in a condensation prone house which resisted other treatments, I would certainly consider a product like this.

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    1. Thankyou Mark. I figured what you were trying to say. It's been enlightening to hear the responses. New house probably doesn't need it unless it was badly built. Old houses probably do.

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  18. i have just had a drimaster installed and by god do i know it my house has become an ice box from top to bottom. I have a really bad draught at the top of my stairs now which carries thru the rest of the house yes but neva actually warms up. I am running my central heating constantly to try and replace the heat loss thru this silly machine

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  19. Fitted the drimaster 2000 unit a week ago. Reason: black mould around and on most windows, water streaming down some walls, toilet cistern etc all as a result of making my 100+ year old energy efficient and tight as possible. Dammed if I was going to muck about with de-humidifiers and pay more on energy costs. Result: after 24 hours humidity readings on my weather station dropped from ave 80% to ave 60%, ALL condensation has ceased and my downstairs is warmer. Additional: my unit is set to speed setting 4 due to small size of house (2 up 2 down) and proximity of wall (650mm). Even the kitchen and bathroom are dry and I have no extractor units yet. Summary: I am well pleased, if this unit is fitted correctly and for the right reasons it will make you happy!

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  20. Can someone advise, does the Drimaster Heat have to have a seperate power cable to the little grey heater control box on the side ? Mine only seems to be connected to the mains by a little seperate black transformer box. Thanks

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    1. The heat element needs power from the fused spur.
      Nuaire tell me that the current is low and the lighting circuit can be used.
      The tempering heater then switches on when air temperature drops below the "chosen" temperature.
      Each unit has instructions but if you are advised to have any unit checked by an electrician.
      Dryhomes recommend the 'Heat' is used in bungalows as the incoming air is close to the occupants - in a normal house this is not the case. Their website is very helpful

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  21. We are renting and had some condensation problem for several months (since we moved in). Surveyor recommended to fir kitchen and bathroom fan. Unfortunately landlady decided to use some cowboys to fit Drimaster 2000 which is a complete failure. The whole unit is a super large fan fitted into your loft, sucking cold air and blowing it into hallway (usual place). This is not heat recovery unit!!! We now have super cold air blowing into our house and have to double heat with radiators. Mould did not disappear. If you have condensation problem fit first bathroom and kitchen fan. Open window when having shower and cooking. Get washing mashine with dryer and dry your clothes not in well ventilated room closed from main house. Drimaster is a waste of money and I would not recommend this to anyone.
    p.s.
    We are living in new build 1980 with insulated cavities, ceiling etc.

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  22. we also have one of these fitted. it will help with the condensation. But the house does be freezing, its pumping cold air down from the roof space in the middle of winter, madness. So we have turned it off. And now where stuck with the black ceilings etc

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    1. after reading these posts I have decided to install an extt.fan in the bathroom and kitchen.I will go for a continuous running trickle fan boosted by a humidistat for the b/room and just a humidistat controlled fan in the kitchen.I Think this should do the trick any comments? cheers.

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  23. bri the ppu guyJune 27, 2012

    ive just stumbled across this blog by accident,the positive pressure unit is wrongly critized in the above posts,these do work. i have installed lots of units for the firm i work for and we have yet to have had any complaints, in fact everyone from one off domestic installation to commercial landlords rave about them, and usually they see the benefits within the first week. a few posts stated that their units are actually blowing in cold air! well the answer to this is they have been fitted wrong!every unit comes with factory default settings which should never be relied on because every house has different requirements,every unit should be set up by the installer to suit requirements. p.s owning a screwdriver does not qualify you to fit these units!!1

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    1. Hi there, we are thinking of buying the 2000 model for our 3 bed bungalow, what in you experience would you recommend, I like others get very confused with it all and saw your write up, please could you advise me and others who click onto this page.

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  24. AnonymousJuly 07, 2012

    Owning a screwdiver does not qualify you to fit these units.
    TOTALLY AGREE ! There are far to many fixtures and fittings installed by DIY merchants, who cannot even read (or want to follow manufactures instructions)! These units are the business,
    (when installed correctly). !!!!

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  25. AnonymousJuly 07, 2012

    PIV is the way forward. We have sealed our homes tight. I have a EnviroVent unit after suffering lots of condensation on my windows

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  26. AnonymousJuly 07, 2012

    I agree. My unit has completely solved my problem. Definitely would recommend

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  27. I have just moved into a house with a drimaster, it is blowing cold air. Having not had this fitted myself I don't know how long ago it was installed. How do I go about getting it running properly?

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  28. For gods sake! Anyone thinking of buying one of these (like me) is totally screwed now after reading this.
    Comment 1. Drymaster is amazing. It works 100%. My house is warmer.
    Comment 2. Drymaster is rubbish. Total waste of time. My house is colder.
    Brilliant!

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    1. Do not be put off, these units work fine if installed correctly. Lots of people think they have to use boost because their home has a big problem and are not fully conversant with the system. These units work best on a constant low volume setting, they need to be set up and positioned correctly and they need to be serviced with new filters (which are not expensive) fitted regularly. As with everything in this world there are too many ignorant people screaming wrong opinions with no subject knowledge. Instead of shouting it does not work, try telling us what you have done to address the situation. If I bought a new car and went online shouting its useless, it uses loads of petrol, makes lots of noise and gets nowhere fast!, you would be sceptical of my comments yes? If someone showed me how to use the gears to suit the road conditions instead of slamming my foot down and going everywhere in first gear, do you not agree I would have a far different driving experience! Well it is the same with PPU's/PIV units (they are the same thing by the way)

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    2. I have had this installed. After a week most condensation had disappeared. Throughout last winter humidity went from over 55% to around 40%. no more mould on the walls. Dry windows. Less heating, I went from £90 a month to £60 a month in 3 bedroom semi- detached.These are facts. The house feels more comfortable. The very sceptical installer was now impressed and was going to recommend these. of course subjective, still a good indication. I'd recommend these wholeheartedly, and have done so.

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  29. Drimaster 2000 PIV will work effectively IF diffuser sited correctly,fan speed and IHR set correct for property and Unit installed by a Nu Aire approved installer. It will also improve the air quality if your area is subject to Radon Gas. NOT a DIY job and not for Cowboys. Allegedly heat gain from loft more than covers minimal running costs. Have spoken to people who have had these fitted and all say worked ok.

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  30. I agree, before considering a PIV make sure the property is *properly* insulated, the wall cavity/loft, and there are no leaky windows, vents, ceilings and so on.

    Otherwise you'll suffer from the exact same problems and you'll have cold/moist air pumped throughout your property exacerbating the problems.

    If a social landlord foists one of these on you, get them to check the above first.

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  31. I inherited a Drymaster in my bungalow and did not know what its purpose was until the flexible duct came adrift from the fan unit. I soon found out what the Drymaster did as within days my windows were streaming with condesation and water was dripping from my bathroom ceiling. A roll of duct tape was all it took to repair the unit and the condensation vanished.

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  32. I have been installing drimasters for over 12 years now and have only had 4 unhappy customers and with the 5 year warranty it is well worth the money. If you install even the basic unit you will notice a difference in air quality and in some cases as quickly as 24 hours your condensation will be reduced. I have removed units and then had to reinstall them as the home owner didn't realise how much it helped.Mark looks like one of these people who likes a grunt without seeing one over a long period of time. They help with asthma as well as the air is fresher and if you have one and it feels cold in your hallway then reduce the speed by 1.They are simple to install but there are many differences in prices so do shop around. I cover Northern Ireland

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    1. Glenn , i live in NI ( randalstown) and this blog has just blew my mind. I have had a couple of good reviews by others but reading this makes you doubt. Who do you work for and I will call you to discuss the fitting costs etc as I was going to buy and fit myself.

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    2. Did you ever get sorted? We are getting one of these and as I also live Randalstown so was just wondering?

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  33. Hi, I have installed one of these PIV systems into a rental property which was suffering from condensation. Tenant induced. The PIV we installed works a treat. The house is always clear of condensation now and always feels fresh when entered.

    Another benefit of PIV is, when using standard extractor fans, not the heat recovery type, the PIV's ensure there is a flow of air moving to the extracts ensuring that they work as intended. A standard extract with no supply air will struggle to move the stale air they were installed for in the first place.

    I now specify these on all larger house extensions where practical, where there won't be an effective whole house heat recovery system fitted.

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  34. We've had one 3 yrs now, and it's on a timer overnight, stops the place feeling colder in winter.

    Doesn't completely eliminate the condensation on the windows but then it's only on for 8hrs a day.




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  35. I fitted one a week ago and the difference is like night and day. No more condensated windows, ceilings walls. I will do one last mould treatment and see what happens. If you get draughts turn the unit down, it's not rocket science. I had my speed setting on 4 and had to turn it down to 3. In summer i will try it on 4 again but it is too strong for winter, hence the draughts. I have been in my solid concrete walled house for 23 years and have struggled with condensation for years. I wish i had found this unit sooner.

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  36. This comment has been removed by the author.

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  37. Can anyone here suggest a trusted 'installer' of those kind of units?? and what are the average costs of installation?? many thanks...NORTHERN IRELAND (LISBURN)

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    1. Hunter Radon Control, they are based in Cornwall but work in Northern Ireland aswell. I used them to fit a Nuaire unit to deal with radon gas and condensation, wow what a result, big reductions in both. Dont have their number but if you google them they come up.

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  38. Zajcev80 look at the BPEC list of installers or contact Nuaire directly I am sure they can guide you to who can install the unit. They were very helpful with me.

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  39. I have one installed and the house is very cold at the moment. Nuaire advertise an "Eco Dri Heater for attaching to a Drimaster unit". Can this be attached to an already installed drimaster 2000 and if so how?

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  40. yea easy to add to a existing insulation no problem

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  41. If anyone hates their Nuaire Drimaster and thinks it's a stupid idead to be drawing freezing cold damp air into their house, do what we did and pull the fuse out of the little box next to the unit LOL

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  42. I am thinking of getting the 2000.but whats the diffrence to the standerd one.

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  43. Any one got experience of the Flatmaster model designed for when there is no loft. I have a ground floor flat with serious condensation. bathroom is internal (no windows) and has extractor. Kitchen is to the rear of the living room and away from external walls for extraction.

    If I go for the flatmaster should I consider the extra for a heater on it - how much does that change running costs? and can it be switched on and off independently of the PIV action?

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  44. Where can I start, I bought a flat last April, 1st floor, 1 bedroom, it was converted from a house in 2008.The house was built in the early 1950’s, it has a metal roof and concrete guttering. At the moment I do not live in the flat, I rent it out. The young woman has complained about the condensation on the windows and some black mould on the bottom of the widows; she opens the windows and uses a condenser tumble dryer. I bought a dehumidifier which cost £230 and she has seen no change, since starting using it (after Christmas).
    I got one of the large damp-proof specialists plc to carry out a quotation and the surveyor said I needed a passive ventilator and a condensation control positive input unit costing £1100. +VAT.What is this and do I need it? Will this kind of machine make the rooms’ cold and do these things work? The condensation control positive input unit will be on the side wall (end of terrace) in the front room and the passive ventilator will be placed in the bedroom.
    Also I got a local electrical and plumbing company (whom I am told are good) to have a look at the flat, he said. The down stairs entrance hall needs a small radiator (It’s very cold there) and a small radiator on the small landing helping to heat the small kitchen which has no radiator.
    In the bathroom the extractor fan needs to run for longer, he said have a remote humidity sensor unit installed to inform the extractor fan when to cut off. And the door needs more of a gap at the bottom. Also he wants to make sure that the ducting is attached to the front and back of the extractor fan, (so the water does not seep in to the brick wall).
    In the kitchen, the cooker hood extractor fan might not have any ducting linking it with the outside vent; he could fill in blowing into the kitchen.
    I need a better thermostat/timer/programmer, one that can be left on low and then comes on higher when you come in from work etc ; needs to be y-less and it needs to be moved from the front room to the landing.
    The widows are double glaze PVC (put in 2008) with vents; in the front room and bedroom the windows have two openings; one of the opens in both rooms do not close properly and he said the window need reveals around the edges because this can cause cold spots and the windows need more silicon around the outside edges. I am getting a double glaze person to look at this.
    Outside the down pipe is leaking and needs to be replaced and the concrete guttering needs to be relined, I jointly own the freehold with the person on the ground floor and we will sort this out in the spring. The person on the ground floor has not problems with condensation. What the builder thinks is that I need to do small jobs first; then look at the passive ventilator later system later.
    The builder also said it’s a good idea to paint the walls in the bathroom and kitchen not with emulsion paint but with Kitchen/Bathroom paint; what’s the best paint to use?
    The ceiling has some insulation but I am not sure how much (no roof void), the builder thinks its ok.
    The builder also said that it was a cold day when he went and the heating was on but the place felt cold.

    The double glaze man just got back to me; he said the two windows were not put in right to begin with; yes there are some hair line cracks in the silicon and if you put reveals in, it will spoil the look of the windows. He said the flexible strip draft excluders (foam) I put around the widow opening are doing the job and it’s a waste of money to take the windows out and to try to fit them back again. And it will not make any diffidence to the condensation. Also the dehumidifier was not on today; it’s a mild day to day but should it not be left on.
    And whats the best make to buy if i need a passive ventilator and a condensation control positive input unit .



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  45. The drimaster with a heater has done wonders in my house, a fantastic piece of kit and virtually maintenance free... well done nuaire

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  46. I like your blog post. Keep on writing this type of great stuff. I'll make sure to follow up on your blog in the future.
    Sash Windows Edinburgh

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  47. I have a bungalow and it suffered from condensation. Put the drimaster unit in and its gone!! Brilliant unit

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  48. My bungalow suffered from awful condensation, windows and north facing wall were dripping wet. I had the system fitted in 2006 and the next day, virtually no condensation, the day after, no condensation. Apart from fitting new filters last year, I've had to do nothing. I have had NO CONDENSATION since. The only down side is that the hallway in this freezing weather is colder because of the cold air being blown in. I will happily live with this in my DRY bungalow. I highly recommend this and it was well worth the installation costs. Finally it's really cheap to run

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  49. OK so can anyone tell me monthly running cost of this unit?? with or without the heater??

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  50. If anyone wants more information on the Nuaire PIV systems like the Drimaster and the Flatmaster, just go to our website and have a good look around as there is lots of useful information there.

    As you can see from our website name we are in Cornwall but the information is still useful even if we can't actually fit one for you!

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    1. Sorry, I didn't realise the url would be hidden in my user name!

      www.cornwallmouldbusters.co.uk

      @zajcev80 The runnning costs of a Drimaster system are about £1 per month but you only need it running about six months of the year so £6 per year! (There is a thermal cut out when the loft gets over 23 degrees centigrade)

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    2. just to make it 100% clear ~£1, is that the price WITH THE BUILD IN HEATER WORKING?? Many thanks, don't wanna spend few hundreds pounds without knowing everything...

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    3. £1 is without the heater - the fan is only a 16 watt fan and on the lower settings usually uses a lot less than 16 watts. The heater is an additional 500 watts so can cost considerably more per month but not every property needs it. Most of the time we install the standard Drimaster as that is usually sufficient. The heater has a setting on it to set a trigger temperature and this can be adjusted.

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  51. could anyone help please? i have a converted attic bedroom in my house and it is always really hot. i have heard that a good way to cool it down is to have adequate ventilation fitted.

    Would a Nuaire Drimaster help if fitted in the attic bedroom?

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  52. I am the person who bought the flat last April, 1st floor, 1 bedroom, it was converted from a house in 2008.The house was built in the early 1950’s, it has a metal roof and concrete guttering. At the moment I do not live in the flat, I rent it out. The young woman has complained about the condensation on the windows and some black mould on the bottom of the widows; she opens the windows and uses a condenser tumble dryer. I bought a dehumidifier which cost £230 and she has seen no change, since starting using it (after Christmas).
    WHAT HAVE I HAD DONE SO FAR
    1) In the bathroom I have had a remote humidity sensor unit installed to inform the extractor fan when to cut off.

    2) The bathroom door cut at the bottom. .

    3) A small radiator on the small landing helping to heat the small kitchen which has no radiator.
    4) In the kitchen, the cooker hood extractor fan might not have any ducting linking it with the outside vent; he could fill in blowing into the kitchen.
    5) I had a better thermostat/timer/programmer, one that can be left on low and then comes on higher when you come in from work etc ; its y-less and can be moved from the front room to the hall.

    6) Work to be done.
    I am going to have the outside the down pipe replaced and the concrete guttering relined. Cost £750.00 +vat which I am ok with.


    7) I am going to have the positive input passive ventilator with heater put in to the built in the wardrobe in the bedroom, which will run from the outside wall to the internal hall will be on the side wall, costing £850.00 +vat. Is this lot of money?

    8) I could not have a small gas radiator put in the down stairs hall because of the pipe work. Should I install an electric radiator and what is a good make .I have been looking Dimplex EPX750 750w Panel Heater with Electronic Thermostat.

    9) Good news, the ceiling has some insulation and it’s ok.

    10) Bad news, tenant has found mould in the built in wardrobe in bedroom (back of wardrobe backs on to kitchen wall). Should I put insulated plasterboard that incorporates a vapour check on the warm side on the walls and how to I do this, what should I buy (Make) and how much does it cost. Can you glue it on to the wall or do you have to use battens because of the air ventilation (cold + warm air makes mould) Can I do it myself? Or should I buy a Dampp-Chaser 48" (120cm) 36-watt Cupboard / Fitted Wardrobe Heater put in and will this help.
    11) If I carry on with the work not including the plasterboard work but have the heater option, I would have spent around £2800.00 any help or ideas please.

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    Replies
    1. Hi

      All of the above will help but the biggest difference will come from the PIV (Flatmaster) in number 7.

      Tenants will always do what you don't want them to do and the PIV is on whether they like it or not! In our extensive experience with tenants, the main factors we find are heating not being used enough and therefore no windows being opened unless there is an inspection that day, double glazing and drying of clothes inside even if they have a tumble dryer as it expensive to run.

      The PIV is always on and provides the ventilation that the tenants seem determined not to provide.

      Personally I would put the PIV in and then see what else needs doing as you will see vastly improved air quality with a few days if not weeks.

      Price wise, we normally charge £595 for the basic Flatmaster but the Flatmaster 2000 with the built-in heater normally costs £695 including cutting a hole through the outside wall. On that basis your quote is a bit excessive but without seeing the property it is difficult to make any more comment than that as there may be other factor in the installation that we don't know about.

      Ian Datson, Mould Busters
      www.cornwallmouldbusters.co.uk

      Delete
  53. Thank you Ian for your feed back, I am going to go for the Flatmaster with heater. its London prices, what can I say. I am going to get reveals put around the window in the bathroom because the paint is peeling of, at the edge of the PVC/ cold spot? I think?. And hopefully the damp/mould in the built wardrobe will clear up once the Flatmaster is up and running. We will see.

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    Replies
    1. even with this system bungalow still smells musty clothes etc really fed up with smell local council say theirs no smell want to live with it

      Delete
  54. Interesting to read the various comments about PIV. It appears that some people do not know how the system works and blame any continuing problems on the tool!
    A reply to Anon on March 20: the drimaster draws air from the loft and normally this would have some degree of heating from sun on the roof and/or heat seeping from the rooms below. Sounds like you could have done with a unit with a built-in heater.
    To Stuart Robson and his hot attic, a drimaster would not really do the job. You'd be better fitting a decent extract fan to pull cooler air through (I'm assuming overheating due to sun on the tiles and that there's no problem in winter)

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  55. Andy NorwichOctober 16, 2013

    I have read many reviews of these systems some good some bad. I am not covinced they work. Where does the moisture go, are they noisy, do they hum or vibrate ?. If any installer would like to fit one in my home for free and if it works I would then be more than happy to pay and endorse their product with great pleasure.

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  56. Hi Andy Norwich

    As they are a PIV (positive input ventilator) they pressurise the property with dryer, warmer air taken from the loft and push the moisture out through natural leakage point in the house such as extractor vents even if not turned on, trickle vents, gaps around windows/doors, etc. They are not very noisy (less than 25 decibels even at high speed) and are typically hung off a cord around a roof joist to avoid any vibration. Basically they provide the ventilation that most modern homes do not have as they are mostly double glazed sealed boxes!

    Most installers like us offer them with a 30 days guarantee that if they don't work to your satisfaction, we will remove the system and give you your money back!

    We are based in Cornwall where it is naturally damp anyway so we get a lot of problems and so far have only had to remove one system out of over two hundred installations so far. That one system was a little old lady who had "dry eye syndrome" and the system dried her out too but she couldn't see properly! She was very upset as the system had solved her "damp" problem but she just couldn't live with it.

    Our website has lots of information on the system and even if you don't buy from us we are very happy to talk to anyone who wants to know more about the systems.

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    Replies
    1. Andy NorwichNovember 25, 2013

      Thanks for your reply. Visited your website and found some very useful information. The only problem I have is finding someone in Norfolk who is likely to do the same deal as your company, as I presume that you don't fancy coming all the way from Cornwall to fit one.(LOL)

      Delete
  57. Anyone know of anyone who fits these units (drimaster with heat) in Newcastle upon Tyne?

    Read all the reviews, and think we'll give it a go.

    ReplyDelete
    Replies
    1. Hi Erika, Contact D.T.C (Damp and Timber Consultants Ltd) on 0191 4160600
      We supply and install PIV units along with a full range of condensation products. More than happy to carry out a survey to determine the most appropriate solution to your condensation problem.We have been installing PIV units for over 10 years and have found them to be very effective with no negative feed back to date.

      Delete
  58. Marcus PayneDecember 13, 2013

    Looking to have this installed in my Victorian rental in Southport.
    Anyone recommend a suitable fitter?

    ReplyDelete
    Replies
    1. Hi Marcus, did you get one installed and if so by who???

      Delete
  59. Hi All,
    I installed a Nuaire Drimaster 365 in my 1970s house for the reason of improving my Asthma as the unit increases the ventilation around your home. It is not designed or intended to replace any medication so if in doubt consult your doctor. I am not technical and the review is written from my own opinion based on my own experience and I am not responsible for any issues you may experience. So here goes...

    The principle of the unit
    The Nuaire Drimaster 365 is designed to be on 24 hours a day 365 days a year. When the temperature in the loft is a certain heat, the heat is drawn into the unit and is filtered before expelling the air back into the house, basically recycling the heat. When the central heating is on the Drimaster basically forces the heat to remain down in the room instead of the heat rising and causing heat loss. When the temperature is too cold in the loft and too cold outside the heater element kicks in and gently heats the air before it is expelled into the house. Some people may experience a cold draft when walking underneath it, but you have to understand the temperature of the air blown down is not matching your room thermostat temperature so you will notice the difference, more so in winter. You could also always turn down the fan or turn it off if you want but then if your going to turn it off during winter then don't buy a Drimaster 365, instead get a cheaper model.
    In summer the temperature of air in the attic is usually higher than that of the outside, so it draws fresh air in and the filter sit before expelling it into the house.
    You also have to install a very small and discreet little sensor that tells you when the unit is going into heat recovery and when the filter needs replacing - generally every 5 years.

    Installation
    I installed the Drimaster 365 myself and it was pretty simple for the average DIYer. First I cut a hole in the ceiling of my upstairs landing almost in line with the stairs, but take your time doing this bit and check your measurements carefully and ensure your not going to cut through any cables above. I made a cardboard template and use blutak to fix it to the ceiling so I could check the position of it. I also paid the little extra and purchased the heater unit. The installation guide for the Drimaster 365 is very clear and simple to follow but if you get really stuck you can always call or email Nuaire and you will find them very helpful.
    The Drimaster 365 must be attached to a fused spur and this in turn I plugged into the mains. I have power in the attic already so mine is powered from a fused spur that is then connected to a 3 pin plug, but it only needs a 3amp fuse so consult an electrician as they may be able to put it into the light circuit but I wanted the facility to turn my on and off and my attic floor is boarded so I could not wire mine into the light circuit. I then cut a 6" hole in my gable wall and installed the external intake accordingly and used fireproof sealant to seal around the external vent. I recommend you use a proper hole cutter and his can be hired with the appropriate drill. Basically that is it - Job done

    Review
    My unit has been installed for 12 months now and I wish someone would have warned me about smells. The unit will not prevent smells coming into you home so on Firework night I had to turn the unit off. Also I have a lovely neighbour but when she cooks a killer jerk chicken my house smells of it and it only annoys me because I don't get invited round for dinner. The way to resolve this I guess is to line the attic gable between the houses but that is really only a small issue.
    In closing I find it easier at night and sleep better and the unit has helped my Asthma an we do sleep better at night. We have also noticed some cracking in the plaster but not sure why.
    What I do notice is in the winter mornings my house is lovely and warm and that is without the heating on, so now I do not put the heating on until around 2pm so I have saved money.

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  60. I did not go for a Drimaster 365 because it looks too complicated and expensive. instead i got a cheaper Drimaster-heat. It works brilliantly in my bungalow. had it running a few weeks and have told all my friends. The unit was bought from dryhomes who were very helpful and was fitted in 2.5 hrs by a local electrician. Total bill added up to less than £400. Money well spent.
    I tried everything before buying this and nothing worked. Bill

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  61. we had the Drimaster 2000 fitted last year cured mouldy smell but both me and my husband have suffered with sore throats ever since

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  62. Had my drimaster for a few years now, with little or no problems, I have a problem at the moment where do I get a replacement sensor which is in the kitchen, or has my drimaster shut off due to the heat in the attic ??? I live in a bungalow

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  63. I have plans to build a bungalow ... the architect has put 2 PIV units in the plans located in the hallway. Is a PIV unit really necessary in a new bungalow ?

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  64. Ive the drimaster heat and fot the life of me never feel the benifit of the warmer air only a cold draught. Whats the best setting so I feel a little warmth please.

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  65. I have a VentAxia bathroom extractor venting directly into the loft space. If I install a PIV unit what should I do with the VentAxia? If I add ducting to the eaves will that be sufficient? will the ducting have internal condensation?

    ReplyDelete
    Replies
    1. I'm not a trades-person just an active home-improver but in my opinion
      you should not be venting a bathroom fan directly into the loft space,
      you are only going to give yourself some serious problems later on.
      Where fans have to be ducted through the ceiling up into the loft, there should be a 100mm flexible foil duct run from the fan to the either the soffit or use a rigid pipe to an exit point out of the roof, e.g. through the tiles.
      If you use a 4" rigid vertical pipe you can insulate this will flexible foil backed bubble insulation to reduce any condensation within the pipe. You should also put a mushroom vent cap on the vertical pipe to stop rain coming directly back down the pipe.

      Delete
  66. I did a lot of searching about this product before getting one installed, swung by the strength of positive reviews. As Mark wrote, the contradictory reviews are reminiscent of Trip Advisor.

    After two months of persevering, I switched our unit off due to its effect in reducing internal temperatures. We have a triple glazed house and don't need the heating on until the outside temperature drops to about 8º C. But the Drimaster pumped cold air in from our loft space making it very uncomfortable from the end of September, cancelling out all the benefits of our windows.

    Going back to the reviews here and Amazon, I now suspect the manufacturer puts resources into drowning out the dissenting voices with positive reviews.

    Some of the claims made for the product are nonsense - like its ability to warm the house by bringing in warmer air from the loft. After monitoring temperatures in my loft and bedrooms this year, there were no days between July to December when the loft air temperature was warmer than inside the house except for when the loft rose above 23º (and the Drimaster is programmed to cut out).

    For anyone with a damp problem, buy a hygrometer and just open the windows when it measures 70%, always run extractor fans in bathroom and kitchen when producing steam and never dry washing indoors (except in a drier vented to outside).

    ReplyDelete
    Replies
    1. Turn your fan speed down if its making the house too cold!

      Delete
    2. I'm a positive person, and vocal, but nothing do to with supplier.
      Personally, I reprogrammed mine to (IIRC) go into heat recovery mode at 18' and shut off at 30'c. And yes, I notice it - not a lot, but the house is cold and landing cold, but when you notice the fan is faster the roof is warmer. I will agree entirely the benefits of this do not outweigh the cost of running the heater aspect over winter. But for me the cost of this is well worth it - just today I got the torch out and looked behind all cupboards/wardrobes etc - and 100% clear (bar spiders web). Thiat makes it well worth it.
      Of course, you need to look at other reasons air is getting moist, extractors and drying clothes elsewhere - but the PIV makes the difference for me.
      FYI - my personal blog had a post (now moved to http://www.drimaster-piv-condensation-system.co.uk/ ) - and I can assure you every post is from a unique person and they all have genuine comments. Nothing staged or encouraged. Also look on moneysavingexpert
      If you don't have the heater, then that is a mistake IMO - the heater takes the chill off and whilst the landing is (as always was) cold, the only difference is the elec bill lol! (IIRC I set heater at 15')
      Loads of info out there.

      Delete
    3. Ryan

      Is it easy to change the default settings for the heat recovery and heater? My bungalow is north facing and cold even in summer made worse by the high relative humidity levels. The temps you mention sound what I would like.

      Delete
  67. Hi Mark
    I used your blog as research when I looked, and then bought a Drimaster heat and worked well. I blogged on my travel blog and got lots of interest, so just whacked up a quick info site based on my research - http://drimaster-piv-condensation-system.co.uk/ - which may be of use to your readers too. Hope you don't consider it a spam post, but hope it is okay.
    Thanks
    Ryan

    ReplyDelete
  68. Hi everyone. I am considering buying a PIV Flatmaster for our 2 bedroom flat. The only place I can mount this is in our boiler room. There is a hole close to the boiler's exhaust outlet, is it ok to mount the inlet of this product close to the boiler's exhaust outlet?

    Also our double glazing windows are very sealed, do I need to install trickle vents to let the stale air out after install?

    Thank you.

    ReplyDelete
  69. Boiler flues vent combustion products to the atmosphere, that consist largely of carbon dioxide, but also carbon monoxide, sulphur dioxide and other noxious gases. Definitely not something you would want to bring into your home!

    Building Regulations require appliance flues to be 300 - 600 mm away from any opening into the property, depending on the power of the appliance and position of the flue. I would leave a greater margin myself.

    ReplyDelete
  70. Derek ConwayOctober 05, 2016

    Had a drimaster installed for 3 years but now seeing the condensation creeping back. Contacted nuaire and was told that it would cost me money to send someone out to check unit even though it is in warranty. Typical sales man told me the warranty only covers broken parts and unit probably needs servicing which is a labour cost not covered by 5 year guarantee they gave me. Robbers!

    ReplyDelete
  71. Had one of these fitted few years ago our condensation drastically reduced now only a minor problem on the coldest of winter days. How ever I switch it off this summer because it recirculates the heat from my hot loft. New neighbours moved in to the house next door (smokers) and the smell of cigarettes filled my house, we are non-smokers and have a toddler... Desperate, I switched it back on and with in two days the smell completely disappeared from every part of our house!

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  72. Hi I have had a flatmaster 2000 fitted today unfortunately I had a hospital appointment and was unable to speak with the installers, my question is – is the red button on the outside of the unit an off/on switch, also how do I turn on the heater part of the machine as the air seems to be very cold and there doesn’t seem to be anything on the outside of the machine like a heater switch, I had thought it would have a heater and a thermostat to regulate the heat ….thanks for any help you can give me They did leave me a manual but it only explains installing nothing about what to do to turn heat on or change the speed of the fan etc

    ReplyDelete

  73. Hi I have had a flatmaster 2000 fitted today unfortunately I had a hospital appointment and was unable to speak with the installers, my question is – is the red button on the outside of the unit an off/on switch, also how do I turn on the heater part of the machine as the air seems to be very cold and there doesn’t seem to be anything on the outside of the machine like a heater switch, I had thought it would have a heater and a thermostat to regulate the heat ….thanks for any help you can give me

    ReplyDelete
  74. This could almost be a Marmite moment. I had a Drimaster installed in my loft to remedy a radon problem (so running 24/7 essential) and this was my experience (which led to it being removed and replaced by a sump system):
    1. The fan had to be run at its maximum speed to effectively reduce radon levels. At this setting the noise from the unit was too intrusive at night.
    2. To be effective the house needed to be sealed otherwise the positive pressure aspect would be compromised. However, in warmer weather windows had to be opened militating against the effectiveness of the system and
    3. at any speed setting on hot sunny days hot air being blown into the house was particularly uncomfortable and brought with it roof and outdoor smells.
    4. During cold weather heating had to be turned up to counteract the cold air being blown in which turned a landing and hall into an ‘icebox’ with temperatures going below 10c at times. Also smells still noticeable but much less than in hot weather.
    5. Although capable of eliminating the radon problem there were too many negatives to live with. However, it did eliminate most condensation from the bedroom areas (a 4-bed house) but at a cost to the heating bill!
    Although my problem was radon I cannot see that this system would have been acceptable, to me, even as a remedy for condensation. However, there is no denying that it can reduce condensation and if only needed during colder weather, at lower speeds, it might not be so difficult to live with.
    Hope this helps.

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  75. After having cavity wall insulation installed in our Victorian semi, it reduced the natural (and drafty) airflow which had previously ventilated the whole house. The result was a warmer but damper environment during the winter months, which was particularly noticeable in our loft (which constantly dripped with condensation) and on the windows which ran with water – particularly the bedrooms in the mornings.

    I had six tile vents and an enlarged soffit vent fitted to cure the condensation in the loft, but it only reduced the problem very slightly. And it made no difference to the windows, which constantly developed black mildew – which needed to be cleaned throughout the house every couple of weeks.

    I spent about 2 years trawling the internet and considering various options before my mother-in-law bought us a Karcher window cleaner.

    Every morning for 2 months I spent half an hour hoovering up a pint of mildew-infused grey water off every window in the house. As satisfying as this felt, I knew I was only dealing with the effects of the problem – rather than the cause.

    The final straw came when we began decorating our boy's bedroom and discovered large patches of black mildew behind all the posters, shelves and wardrobe.

    I would have bought a drimaster sooner, had it not been for its mixed reviews and rather expensive cost. But by now I felt it was worth the gamble.

    I'm not sure why anyone would want to buy the version without the heater. Of course it's going to cause a cold draught out of its vent whenever it gets cold in the loft. So I bit the bullet and paid £285 for the more expensive thermostatically-controlled version.

    The unit was pretty simple to install, but I don't know why it doesn't come with a ready-fitted plug. So I added one myself. Cutting a hole in the ceiling was the longest and messiest part of the procedure. But the whole job was done in about an hour and a half.

    I was rather sceptical that the Drimaster would have any kind of instant or dramatic impact on air quality. So I bought several hygrometers from Amazon (for £3 each) and dotted them around the house to test the genuine air humidity levels – rather than be fooled by any placebo effect.

    After 24 hours the air humidity had dropped by 12% in every room, and a day later by a further 7%. This drop continued each day for about 4 days. Because it was so gradual, I have to admit that I didn't 'feel' any difference to the air quality.

    However, one week later, I woke up to find running water on all the bedroom windows again! The hygrometers confirmed that the humidity had gone up by 18% overnight, and a trip up into to the loft confirmed that the machine had stopped working. The fan was moving - but only very slowly.

    To cut a long story short, Nuaire were very easy to deal with and sent out a new unit within 48 hours – and the old one was sent back for 'investigation'. Installing the 2nd machine was obviously an annoying experience, but took less than half an hour.

    Two years later, and this second Drimaster is still working perfectly. And despite the initial problem I had, I'd absolutely recommend that anyone with a similar scenario to mine should consider installing a PIV unit of some kind.

    ReplyDelete
    Replies
    1. Your situation sounds exactly like mine. I can't wait to get my Nuaire installed!!!

      Delete
  76. Review part 2 ...

    PROS:
    • Prevents 99% of all condensation and mildew.
    • Reduced the condensation in my loft (by drawing more air through the vents I had fitted).
    • Quiet operation on all but the highest fan setting.
    • Not noticed any increased electricity costs.

    CONS:
    • Nuiare still seem to have a monopoly on the 'PIV' market, so their machines still feel expensive to me, for what they are - as are the filters (at £25 a pop).
    • Noticed some smell coming down from our loft on hot days. This is probably because we have the old-style bitumen roofing liner inside our loft. So I just turn off the Drimaster during the Summer.
    • Apart from the filters (and possibly the heater element), I don't think any of the parts of the Drimaster are replaceable.

    I hope that anyone considering one of these machines will find my review balanced and helpful.

    ReplyDelete
  77. I just had the unaired 2000 (with the sensor) installed.
    The spark didn't connect up the sensor so I did it myself.
    Firstly , what is the reason (in the manual) for having the sensor placed 3m away from the main unit...?
    Second, I set the temp control sectting to; Option 2 at loft temp below 19° the unit will operate at normal operation mode. At loft temp above 18° but below 31°, the unit will operate at Heat Recovery Mode. At loft temp above 30° the unit will switch itself off (standby mode). On this setting my unit switched off

    ReplyDelete