Well like many UK homes our central heating and hot water is fuelled by natural gas. We also use natural gas for cooking on the stove top (the oven is however electric) and we have a gas fire in the living room, but these latter two uses are much less significant.
I’d lived here for 10 years before I started actively trying to reduce my energy consumption. During those 10 years I used an average of 562 units of gas annually.
Since then I’ve reduced my consumption by two routes, firstly to reduce heat loss so that less energy for heating was required, and secondly by replacing gas with renewable sources. It’s however also the case that my circumstances have not been constant during that time so, for example, when I started this I lived alone then 4 years or so ago I married and my wife joined me here; and now my wife is at home during the day with our baby daughter much of the time. Consequently the demand for hot water for washing and heating has increased.
The steps taken to reduce gas consumption include:
- Having insulation installed in the cavities of the house walls. Houses here conventionally have a double skin of brick or block and, when this house was built, the cavity between the inner and outer layers was usually left as an air gap. We’ve had that gap filled with insulation as you would find in newer homes.
- Increasing the thickness of insulation in the loft.
- Replacing the old wooden windows with new PVC ones with higher “A” grade insulation – most easily seen by the larger air gap in the sealed units.
- Installing solar water heating panels on the roof in conjunction with a larger hot water tank. In the summer these provide almost all our hot water (no heating is required), although at olther times of the heat they don’t provide enough heat alone for hot water they can help to pre-heat the cold water leaving the gas less work to do to achieve a usuable temperature.
We didn’t do this all at once, but if I compare the last 2 years to the original 10 year baseline then we’ve reduced average annual gas consumption by 23%. I think that the reduction would have been higher had our circumstances between constant.
We’ve moved since writing this post. In the new house my approach to solar has been somewhat different. The old house had solar thermal to make hot water but this was relatively expensive to purchase and periodically I got chased to get it serviced. The new house instead now has a much bigger solar PV system and diverts some of the generated electricity to the immersion heater. The device that controls the diversion of electricity to the immersion heater (an immerSUN) achieves the same ends as the solar thermal panels at a fraction of the price, and has no need for servicing.