It is cheap and easy to change a few light bulbs to the energy efficient kind but what can you do to make more of an energy saving impact?
Dale Vince from Ecotricity gave the Telegraph some tips using the example of improving his own stone house in rural Gloucestershire. In the interview Dale said “the walls were single skins of stone, so we spent £1,000 filling the gaps with polystyrene and laying plasterboard on top. Then I spent £6,000 installing a thermal store (a larger than normal insulated water tank), a bank of solar collectors on the roof, a heat exchanger and an air force heat pump (which takes additional warmth from the air). For £500 we put in an underfloor heating system using water drawn from the bottom of the thermal store and the radiators feed from the top”.
These ideas sound potentially suitable for those people who do not have a large enough garden for a ground source heat pump or enough wind resource for a wind turbine.
Earth Notes explains that “if the (air source) heat-pump system has a CoP (Coefficient of Performance, ie how much kWh heat you get out for each kWh of electricity in) consistently at or above ~2.3, then the heat-pump solution beats gas.“. 2.3 is the ratio of the CO2 emissions of electricity/gas per kWh.
The web-site explains that air source heat pumps are a “dicier” proposition because the air temperature is likely to be lower than ground temperature meaning your system works less efficiently. Combining the air source heat pump with solar thermal or solar PV is recommended which has the added benefit of allowing export of electricity back to the grid network with the appropriate inverter….“On very dull/cloudy/cold days you would be importing electricity to heat your DHW (eg instead of gas), but over each month (even December), you should be approximately neutral or better, exporting in summer and displacing fossil-fuel burn elsewhere on the grid. (When using ASHP for space heating you’d always be importing for that unless you employed a huge and well-sited PV array.)”
