This year I’m doing another round of efficiency work on our house, with the aim of getting it an A rating by 2020. So far we’ve fitted solar panels and added extra insulation to the loft. I’ve hung thermal curtain linings, and added some insulating film to cold windows. We carpeted a cold front room with insulating underlay, and if all goes to plan I’ll be getting into the crawlspace under the house with more insulation before the winter. The external insulation to the outside of the house has taken longer to organise than planned, as the front of the house needs more substantial work. That will be done in the autumn too.
I began monitoring our energy more carefully in 2018 so that I can measure our progress. It’ll be a while before we can really see the difference, but this week I got our annual energy use summary from Ecotricity. They measure it from the middle of the year, so we can compare our 2017-18 energy use with 18-19.
- Gas use: 5,946 kwh, a 23% improvement on last year.
- Electricity use: 1,543 kwh, a 10% improvement on last year.
Winter last year was colder than this year, with the ‘beast from the east’ and all that. So a chunk of the improvement is down to the temperature. I have looked into confirming the efficiency with ‘degree days’ data from Luton Airport’s weather station, but I got very confused while trying to calculate a baseline regression. I’ve concluded that it’s a level of statistical analysis beyond my pay grade.
What I do know is that each month so far this year has been an improvement on the same month for last year, and that will have to do for now.
In financial terms, Ecotricity records our annual bill at £563. The house generates four times more electricity than we use, and we sell the surplus and benefit from what remains of the feed-in tariff. If I count those earnings against our bill, then our total household energy costs for the last year is £380. By way of comparison, Ofgem calculates the UK average dual fuel bill at £1,254.
Of course, we’ve spent hundreds of pounds this year on insulation, so we’re not better off on net terms. The payback will be over years, and ultimately I’m out to cut our carbon emissions rather than save us money. And so far, we’re heading in the right direction.