Saturday, September 5, 2009

What is a Typical Electricity/Gas Consumption?

I have been trying to find out what is considered a typical consumption. Most houses in the UK (about 80%) use gas heating, which is cheaper per kWh than electricity. The average UK House electricity consumption is estimated as 4,700 kWh/anum

Our house in summer/autumn is using an average of 11.6 kWhr per day which includes one hour/day of heat-pump doing hotwater, plus electric oven, microwave and induction hob, kettle, computer, router, printer, radio, TV, energy efficient summer lighting and Fridge; plus occasional dishwasher and washing machine.

That would work out to 4,250 kWhr annually if there was no winter heating. A gas heated house would use roughly the same electricity/month throughout the year (plus only the extra winter hours of lighting and a bit more telly).

As most houses are gas heated and gas cooking, our house is managing quite a good figure. Take away figures for our electric cooking and hotwater to do it instead with gas would bring our consumption down to the average for a house of this size, of approx 3,300 kWh/yr.

We know that our total annual consumption is precisely 8,500 kWh/yr for the last 2 years, so winter space heating and lighting is causing another 4,250. That is the figure that we have to 'attack' with our Solar Earth Charging project.

How does this compare with a gas heated house? Moneyforums site calculates the average medium size house annual usage as 3,300 kWhr/yr Electricity and 20,500 kWh/yr of Gas. If that is the case, our 4kW roof installation positioned on a south facing roof would generate 3,300kWh, ALL of a typical electricity consumption for the year, for a normal gas heated house. (Sorry to say that with our east facing roof, we will only achieve 2,800 kWh/yr.)
Most gas tariffs appear to be about 6.5p/kWh for first 2,860 kWh, then 3.5p thereafter. See the Energylinx site. While this is the case, it could be used as an argument against the heatpump, because if gas is 1/4 the price of electricity, and a heatpump's best CoP is 4, the two balance out.

In the long run the UK and other European countries may have problems with the supply of gas from Russia, whereas electricity can be derived from renewable sources, including our own roof. So, strategically, we feel safer being 'monofuel' - based on electricity. We could add more to the roof in the future.

On a pure annual cost basis, if we had a conventional house, our electricity would be about £450/yr on a green tariff, and the gas would be about £850/yr. With the heatpump and no gas, it is £1,100/yr. So even without our roof PV and Solar earth charging, we are already doing better. But we want to do a LOT better.

See What You Can Do site, for advice on saving electricity.

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