Dear Mr Brinkley. Thankyou for filling out our home energy check questionnaire: an important step towards using less energy to heat, light and power your home. Using the information you’ve provided, we’ve come up with a practical look at the energy you use and can save at home.
About a month previously I had responded to a questionnaire that had arrived, unsolicited, by mail from the Energy Savings Trust. It asked me lots of questions about my house and suggested that if I send it back to them they will supply me with a mini energy audit. Only I don’t think they called it that.
I was interested to know what they would say because our house is arguably an interesting case. Built in 1992, it was certainly someway in advance of building regulations at the time. In particular, it incorporated underfloor insulation (not mandatory until 2002) and low-e double glazing (back when low-e was cutting edge). The walls had a little extra insulation and the oil-fired boiler heating system was reasonably well designed and included zone control, as well as thermostatic and time switching. It’s a well-built house and it probably rated as a Best Practice for 1992 sort of house, but certainly not an eco house.
The question that I was interested to see answered was what the EST would suggest that I did to upgrade the house. In fact, they have only made one suggestion. That is that we upgrade the boiler to a condensing boiler for a saving of £85 a year. Or, in terms of CO2, 0.6 tonnes.
Funnily enough, we did consider installing a condensing boiler when we built the house. Back then, there was only one oil-fired condenser on the market, made by Geminox, a French manufacturer. Our green-tinged plumber, Norman Cox, was keen for us to fit one, but in the end I took the decision that it wasn’t worth paying the extra £1,000 or so required to fit — cash was tight back in 1992 and I had heard one or two stories about the early Geminoxes which didn’t inspire confidence.
We ended up with a Boulter Camray (now part of the Worcester Bosch group) which has been chugging away these past 15 years. It gets an annual service (cost around £60 plus parts) and it occasionally breaks down. The last time this happened, I enquired from Shelford Heating about replacing the boiler with a condenser but was told that not only would we have to bear the cost of a new boiler, but that the oil tank would have to move because the position we placed it in in 1992 (right next to the house wall) is now regarded as a fire hazard (Part J of the building regs having been “upgraded”). Not only would that double the expense but there is no obvious place in the steeply sloping garden to place a new oil tank. It would in fact represent a major piece of civil engineering. So a replacement boiler would probably end up costing us around £8,000. Hmm. Should have fitted the Geminox 15 years ago, shouldn’t I.
Anyway, I am slowly but surely getting around to the point of this post. The Energy Saving Trust gave us a C rating, based on what I told them. This is sort of similar to the rating we would be getting from an energy performance certificate. I have no quibbles with that: it was what I expected. But the point is that they only made the one suggestion for improvement, which was to replace the old boiler with something more efficient. The saving was actually pretty minimal. Either with or without a condensing boiler, our not very old house still uses a fuck of a lot of oil. Around 2500lts each year (that’s just over a tank full). That converts to just over 25,000kWh, which converts to 7 tonnes CO2 per annum. The Energy Savings Trust estimation is pretty accurate on the size of our oil bill (just about £1,000 with oil at 36p/lt) but grossly underestimates our CO2 footprint: they suggest just 4.1 tonnes of CO2 per annum. I reckon it is over 7 tonnes. Why should that be? Do they use different conversion factors to me? I’m on 0.265kg CO2/kWh, which is the “industry standard.”
So my poser for the day is what should happen to houses like ours? If it was built to Passivhaus standards, or Code Level 4, and was still heated using an oil-fired boiler, it would be burning about a third or even a quarter of this quantity of oil, releasing maybe just 1.5 tonnes of CO2 a year to get space heating and hot water. So, although our house is probably more energy efficient than 90% of the UK housing stock, it still performs miserably in terms of what could be done. But there appears to be no upgrade path apart from fitting a condensing boiler, which really only makes a marginal difference.
I don’t have an answer to this, but it does highlight the enormity of the problem. What exactly do you do to a house that already has cavities full of insulation and has 200mm of the stuff in the loft, but still eats energy like it’s going out of fashion?