House thermal imaging of a 1987 house - Turn from despair to action.

We are a family of four and have been working from home since the pandemic started so having a comfortable and even temperature environment for working, studying and general family life has become more important. Some rooms are colder than others, the floors are cold whilst the upstairs rooms are cold in the winter and too hot in the summer. We always wear slippers and jumpers during the winter despite keeping the thermostat at 21 degrees to allow comfort whilst working.

Our average annual gas bill is £923 consumption (27,000kWh) + £97 standing charge = £1,020. This is 58% higher than the average consumption of a similar-sized house that uses 17,000 kWh.

Our house was built in 1987 in a typical red brick style with four bedrooms and one bathroom plus cavity walls. We moved in in 2004 when we installed UPVC double glazed windows then in 2010 we extended the lounge, added an en-suite bathroom, insulated the loft and the bedroom above the garage. We also replaced all the radiators and installed a new combination boiler and moved it from the kitchen to the garage.


The hot and cold water tanks were also removed. We have a stove but use it only very occasionally. The windows have no curtains just blinds.


Kate Brown did a thermal image of the front of our house during a very cold evening in February 2021 which showed that the front wall had higher heat loss than the windows (whereas building regulations allow for heat loss from windows to be five times greater than from walls). Also, heat loss from our roof is less than the walls. All this points to the fact that our windows are double glazed, that our roof is insulated but that the cavity walls have no insulation. To make matters worse, one of our teenagers had left the bathroom window wide open on one of the coldest evenings of the year!


Clearly, we can only improve some of this! I have done a few searches and come up with a range of solutions with ballpark figures - some of which are cheap and simple whilst others will require more investigation. I don’t know how much savings (£ and CO2) each measure will attract but I certainly don’t think that I need to be scientific about it.


Winter & Other Improvements

Don’t keep doors & windows open for longer than is necessary

Replace Smart meter (ours isn’t compatible with Octopus our new utility provider)

Shorter showers

Front & garage door draft taping £25

Misted window panel to be replaced £150 (source Checkatrade)

Cavity walls insulation £610 (source Energy Saving Trust)

Total £785


The Energy Saving Trust calculator indicates that for a detached house, cavity wall insulation can help achieve annual savings of £255 per year (or 27% of our current gas spending), therefore £785 for winter improvements would have a payback of just over 3 years.


Summer Improvements - desirable only as currently we don’t use a fan or aircon against the heat

Window films to repel sunlight £450 (EvoWrap Coolclear Solar Deluxe 50cm x 20m)

Close all windows during the day and open them in the evening

Total £450


Below is our planned journey to cut down on our gas consumption and CO2 emissions

Beyond this, we need to start thinking about what will be the replacement for our gas boiler as it is 11 years old and showing signs of wear and tear.


Sophie Nelson 30th June 2021



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