29 Sept 2007

How should we manage water use in the home?

The more I learn about the Code for Sustainable Homes, the more uncomfortable I get. I mentioned that I had been in on an interesting seminar last week, on the water use guidelines set out in the Code, and this week I investigated a little further, armed with an Excel spreadsheet.

Water use is one of two mandatory aspects of the Code (the other being energy use). Mandatory, in this instance, means that you have to meet certain targets as regards notional water use in order for the house to gain a particular Code Level. It’s no good building a zero carbon house if it fails to meet the water use standards as well.

The target water usage levels that the Code demands go like this:
• Levels 1 and 2: theoretical 120 litres/person/day
• Levels 3 and 4: theoretical 105 litres/person/day
• Levels 5 and 6: theoretical 80 litres/person/day

Now I guess many people have read the code and noticed these figures and probably thought very little more about them. I certainly hadn’t until I sat in on this seminar last week. Until then, they were just numbers jumping at me off the page: they didn’t relate to anything or any actions. But my eyes have been opened and what I am now seeing is a little disturbing.

The point is that it doesn’t matter how much water you actually use, the Code judges everything by Mr and Mrs Average, Joe and Joanna public, and according to water company statistics, they use about 130lts per day each. They break it down thus:

• They each flush the loo 4.8 times a day (c 20lts)
• They wash their hands or brush their teeth for 40 seconds a day (10lts)
• They use about 25 lts at the kitchen sink each day
• Their washing machines account for 16lts per day each (49 lts per cycle, and J&J each use it once every three days)
• Their dishwasher uses another 4lts per day each
• And then there’s showering and bathing. It gets complex here because Jo likes showers and Joanna likes baths, but overall it evens out and tends to account for 50lts per day each
• I make that 125lts a day each. Give or take 5 lts, that’s it.
• This might have been better with a pie chart, but it wouldn’t have been so much fun.

The standards set out in the Code would seem to indicate implicitly that this amount of water usage (i.e. 130lts per person per day) is unsustainable — i.e. wicked and to be strongly discouraged. The challenge set out in the Code is not to change the washing or bathing habits of Joe and Joanna, but rather to engineer in solutions which enable them to live exactly as they do now whilst consuming much less piped water.

Welcome to the world of water-efficient appliances. Low flush toilets help matters, and that without any apparent pain. If you can specify aerated taps on the kitchen sink and a water-efficient washing machine you can rapidly reduce that notional figure of 130 lts per person per day down to just over 100 lts per day. So far so good. Just as with energy efficiency measures, the first steps are easy and cost effective. So you can get to Code Level 4 without too much hassle.

It’s that 80 litres a day at Level 5 and 6 which is the problem. You see there just don’t exist any water efficient products that can get Joe and Joanna’s usage down to such a low notional figure. That’s where my spreadsheet came in: I was tinkering with all the very low water usage appliances out there and I still couldn’t get below 102 lts per person per day. This includes:

• dual flush toilets that work on 4.5 lts full and 3 lts half flush
• showers that use just 7 lts per minute
• aerated kitchen taps using 2.5 lts per minute
• washing machines using 35 lts per cycle rather than 49 lts

So how do you go that extra mile, or in this case 22 lts, and get the notional consumption down to Code Level 5 and 6 requirements? The answer the Code is steering us towards is, of course, recycling, either via rainwater harvesting or grey water systems. But even by taking this big leap, you are not guaranteed a result. This is because Joe and Joanna, even with the most water efficient appliances installed in their home, are still using more than 80 lts a day before so much as a loo is flushed. Grey water systems, which reuse bath, shower and basin water for toilet flushing purposes, aren’t going to get you under the 80lts per person per day figure on their own. Rainwater harvesting systems can be set up to run washing machines as well as flush toilets and so in theory could get your notional usage figure down below 80lts per person per day, but only if they operate at near 100% efficiency which is unlikely over the course of a year — in prolonged periods without rain, the storage tanks empty and the systems switch over to tap water.

The conclusion has to be that this 80lts per person per day figure is really at the limits of what is technically possible at the moment. It may well be that you have to fit both a grey water and a rainwater recycling system to meet the target. Grey water systems seem to cost anywhere between £1500 and £2000, rainwater rather more. That’s not a problem if you are building exemplar homes for demonstration purposes but remember we are aiming this at every new home built after 2016. That is a phenomenal challenge and a phenomenal expense to be borne.

There are some further strange anomalies in how the guidance has been put together. If you specify a bidet, you take an instant 5lt per person per day penalty; if you specify a water softener, you take a 12.5lt per person per day penalty. It’s hard to see how anyone will be able to fit these into a new home and still make Code Level 6. On the other hand, if you specify a swimming pool or an outdoor whirlpool bath, there is no penalty at all!

Rather than tinkering about with how we distribute water around the home, wouldn’t it be a lot easier and a lot less hassle just to charge the correct price for tap water in the first place? All new homes in England have metered supplies now in any event, so we already have a perfectly responsive mechanism in place for restricting water usage. As has been pointed out elsewhere, there are many parts of the country where water shortage is not and is never likely to be an issue. Shouldn’t the water restriction measures in the Code reflect this?

Underlying this is a debate very similar to the one raging over renewable energy. The government seems to be keen to promote onsite renewable energy (also via the Code) despite all the evidence being that it is much cheaper and more efficient to green the National Grid. With water, there is no national water grid but coincidentally, there is an article in this week’s Building by David Lush arguing that there should be. The main argument used against building a national water distribution system is cost and Lush quotes an Environment Agency consultation paper suggesting that it would cost between £9billion and £15billion. That may sound like a lot, but £2,500 spent on water reduction measures in every house after 2016 would cost £625million a year and would end up surpassing the cost of building a national water grid after 20 years. Neither option is exactly cheap. It may be that we should do both: I am not against recycling grey water or rainwater, but I do worry about the Code’s insistence that we must keep putting more and more stuff into our homes in order to make them sustainable. Stuff not only costs, but it breaks down, it needs servicing. Its all very well enthusiasts fitting stuff, but 250,000 homes a year? Has anyone seriously thought through the implications?

24 Sept 2007

Is this the end of passive solar design?

I learned something about the Kingspan Lighthouse (pictured) this weekend, something that I’d completely missed when I visited it at Offsite 07 in June, where it got star billing as the first Code for Sustainable Homes Level 6 house to be completed. The Lighthouse reverses the conventional wisdom on orientation. There is only one tiny window, indicated by my arrow, facing south. The bulk of the glazing faces east, west and north. In contrast, the south face is almost covered in photovoltaics and thermal solar panels.

Why? It seems the logic is thus. The space heating requirement has been all but insulated out of the house and the free heat arriving from the sunny south just isn’t needed in the winter heating season. And in the summer, south-facing glazing just leads to a mammouth overheating problem. It is, I think, the first house in the UK that identifies summer overheating as a bigger issue than winter warming.

Now whether this novel approach proves popular with the punters remains to be seen. But Potton Homes, recently taken over by Kingspan, feel very confident that the Lighthouse design approach is going to be a winner. They are busy incorporating Lighthouse into their brochure offerings and plan a launch event at the upcoming Grand Designs show, taking place at the NEC, October 5-7.

Coincidentally, this all chimes in with a talk given by Simos Yannas of the Architectural Association last week at the Nottingham Zero Carbon Symposium. Yannas has spent much of his working life studying passive solar design and admitted that he has always been attracted to the concept. Despite this, he has recently and reluctantly come to the conclusion that massive insulation trumps passive solar everytime. If you engineer the house down to Passivhaus levels of heat loss, solar gain just ends up being a problem. It’s unpredictable and uncontrollable and there are very few days in a year when it actually makes a useful contribution to the heating load.

20 Sept 2007

Code for Sustainable Homes: cracks appearing

Just got back from a two-day symposium run by Nottingham University’s School of the Built Environment. There were a number of very interesting and cogent presentations given mostly by academics, architects and materials suppliers, and unusually for an event such as this, an overall theme emerged which could perhaps be best summarised as Code for Sustainable Homes — Whoaaahh, steady on, not quite so fast.

Many experienced voices expressed disquiet about the turn of events over the past twelve months, ever since the government published the Code and announced that it intended to move all new housebuilding to zero carbon by 2016. In particular the Code’s almost wholesale adoption of the PassivHaus standard came in for questioning: its apparent insistence on mechanical ventilation with heat recovery came in for a lot of flack, as was its insistence on heavy and expensive triple glazing and almost excessive zeal in which it promoted airtight construction. There was a feeling that this represented a degree of over-engineering for houses in a relatively mild (and getting milder) climate, where many people still routinely sleep with their windows open. The event saw the launch of a set of different proposals for low energy housing in Mediterranean climates, but the question of whether these were more applicable to the UK than the German PassivHaus standard was left for another day.

There was also a healthy debate about how best to power these post-2016 homes. The Code explicitly calls for the homes to generate renewable energy to cover their own energy requirements, but it remains unclear just where or how it can be produced. The preferred solution would seem to be onsite, but everyone agrees that many homes will be completely unsuitable for onsite production. But once you accept that the energy harvesting can move offsite, you run into all manner of problems of definition. District heating systems? Shares in windfarms? Or just buying power from a green energy supplier? All are possible, but they are either technically challenging (CHP) or are just another version of carbon offsetting (widely derided).

There was also a good deal of discussion about the water saving proposals contained in the code. The idea is that we should aim to be reducing our water use from around 150lts/day each down to just 80 lts/day at Code Level 6, the 2016 standard. That is surprisingly challenging: even if you fit every water saving device, ultra low flush toilet and lo-flow shower, you still struggle to get below a notional 100lts/day. To get right down below 80lts/day requires on site water harvesting or recycling which again was felt to be fine in principle but the thought of rolling this out into 250,000 new homes a year appears to be fanciful at best. But this is what the code demands after 2016.

13 Sept 2007

More on the Timber Frame Fires

My musings over the precise causes of the timber frame fires last month have been noted by the UK Timber Frame Association (UKTFA). Yesterday, I was invited to talk over the issue with Stewart Dalgarno who works for Stewart Milne, one of our two timber frame giants, and who is currently chair of the UKTFA.

He reckoned I had underestimated the amount of timber frame apartment building that is going on. Stewart suggested that as many as 30% or even 40% of the medium-rise apartment market was now being constructed in timber frame and this accounted for 300 or 400 sites at any one time across England and Wales. As far as he was aware, there had never previously been any fire damage on the scale seen at Colindale last summer, since when it’s happened three more times, which is what caused me to raise suspicions that these events are not mere accidents, or even isolated cases of arson.

From the UKTFA perspective, the good news is that, thus far, developers have not been put off by the fires and that order books this year are healthily ahead of last year. It is one area where the speed advantages of timber frame really does have major attractions, because you can’t sell any part of an apartment complex until the whole building is complete, and this remains a strong pull for the scheme financiers.

He also went to great length to show that they were addressing the issue of fire hazards during the construction phase. No one is suggesting that medium rise timber frame is a fire danger once completed, but it does present some unique challenges whilst it is being erected. A report examining the causes of fires and methods of prevention is being finalised and should be published in the next few months, to be followed by a series of training seminars aimed at the construction industry.

It transpires that there is usually only a relatively short period during which a timber frame structure can be put to the torch. Once the walls and ceilings are lined, the building is effectively compartmentalised and the risk of fire is greatly reduced. So one of the key initiatives Stewart is suggesting is that, on sites identified as high risk, the lining process is moved up the critical path as far as possible so as to minimise the length of the time spent in the vulnerable panels open, insulation in phase. Ultimately, he sees the industry moving over entirely to closed panel systems where the linings are done off-site, effectively removing this period of added risk. It may well be that the recent fires will end up accelerating this process, which many already see as inevitable in the longer term.

In the meantime, attention is being paid to tightening up site management and security procedures and ensuring that timber buildings aren’t left open for many months, as seems to have been the case at Colindale. Reports on the circumstances and causes of the three more recent fires are still awaited. In the meantime, there is little more anyone can do but speculate.

9 Sept 2007

Natural House Map

Whilst people may argue about what exactly constitutes a natural house, they can no longer have any excuse for not knowing where they are located. Have a look at this fascinating link.

8 Sept 2007

9 new jobs = 10 new homes

Here in the East of England we are well used to seeing plans put forward for mega amounts of new housing. The usual justification for this is that the economy is expanding fast and that we need new housing to provide space for all the new jobs being created in the region. That, plus the hope that more new homes will keep a lid on ever increasing house prices.

There is, perhaps not unsurprisingly, a close correlation between the number of new jobs being created and the number of new homes required. The ratio seems to be set at around 9 jobs to 10 new homes. The East of England Plan, now two years old, suggested that we would be creating 421,000 new jobs by 2021 and that we would be needing 488,000 new homes to meet the demand created by these new jobs. Since then the numbers have been slowly rising and today we have a report circulating, as reported in the Cambridge Evening News, that the number of new homes we need in eastern England has shot up to 613,000, presumably extrapolated up from 550,000 new jobs.

What no one ever talks about is just what these projections are based on. The East of England is a prosperous area and it’s enjoyed good rates of economic growth for decades. Presumably, these rates are being projected into the future and a percentage point here or there in the projected growth rate results in there being x thousand more jobs and x+0.1 thousand more homes. What you never see discussed is the fact that new houses are themselves creators of new jobs, and hence economic growth.

How can this be? Most new jobs in Britain are in the service sector. As the population grows, the service sector has to expand to keep pace. Each new household brings with it demands for teachers, doctors, nurses, shop assistants, bus drivers, car mechanics, gardeners, jobbing builders, estate agents, hairdressers, office cleaners, you name it.

Another way of looking at this thorny issue is to realise that whilst new housing is an engine of economic growth, it’s an incredibly inefficient one. Let’s hazard a guess here. I reckon ten new homes are needed to fill the vacancies created by just two new jobs resulting from local businesses expanding, and the other seven new jobs result from looking after the residents of the ten new homes. Consequently, the bulk of our economic growth results from drawing people into the region, not from newly-won business deals.

It’s time we took a long deep look at the methodology used to make these projections for both new jobs and new housing. Our aim in the 21st century ought to be to make the existing economy function better, not just expand it for the sake of expansion.

6 Sept 2007

Reflections on Upton

I made my second visit to Upton this week. For those of you not in the know, Upton is the new Poundbury. Sort of. It’s an urban extension (fancy modern term for a housing estate), tacked onto the edge of Northampton, and it’s full of weird and wonderful homes. I was there as part of a Princes Foundation seminar group and the guiding hand of this group is evidenced all over the development, though its much more diverse than Poundbury. Although at first glance it looks all very traditional, there are modernist schemes here as well and Bill Dunster’s Zed factory is hard at work on one corner delivering what they claim to be the first Code for Sustainable Homes Level 6 homes onto the market.

Only the southern side of the development is complete, the rest is still very much a building site. However, enough is there to give an impression of what it will be like when all 1200 homes are all done and dusted. In many ways, it’s the complete antithesis of selfbuild. Like Poundbury, the whole scheme is about urban design and master planning, building model settlements where everything is thought through and everything hopefully functions smoothly. It’s just as much about social engineering as it is architecture and consequently it all has a rather prissy, manicured feel to it.

But behind the glossy veneer of this exemplar development, most of the work is being undertaken by warts–n-all housebuilders and developers, and it’s not an easy site for them. Kim Slowe, of Cornhill Estates, one of the Upton developers, who cut his teeth at Poundbury, gave a very interesting presentation to the group and was quite upfront about the problems encountered. “Whereas homes in Poundbury sell for between £230 and £260 per square foot, up here in Upton we are lucky to get £165. It’s a very different social mix and quality building is a much harder sell. It’s challenging.”

And whereas the scheme density, the parking restrictions and the pepperpotting of social housing throughout the site doesn’t appear to cause any problems in Poundbury, these issues have all become thorns for the developers trying to woo in private buyers at Upton. By way of example, Slowe indicated that theft of building materials was an ongoing issue on this site. “It’s all very well using lead-lined canopies over the front doors, but the lead keeps getting stripped off.” Just around the corner from Slowe’s houses, I walked straight into the evidence that this was indeed the case – see image.

The verdict on the success or otherwise of Upton will be some time in coming, but you have to admire the vision and drive which enabled it all to get out of the ground. Do take a detour to go and visit the scheme and make your own mind up.

BTW, it’s not very well signposted. It’s on the western fringe of Northampton, next to the Sixfields football ground, the home of Northampton Town FC. Set your sat nav for NN5 4EZ and it should take you to Upton Square, the pulsing heart of the place, right next to the brand new primary school.