Generate your own energy assumptions

Important:

These savings provide an estimate only. Actual savings may be higher or lower depending on your energy use patterns, levels of insulation and system design and size.

General:

System costs are typical prices paid through the Low Carbon Buildings Programme grant scheme, and are not based on your size or type of property.

Prices include installation, but do not include discounts from the grant funding available.

The financial and carbon savings are calculated based on your property size and type, and your heating fuel where appropriate.

For the heating technologies we assume that homes with cavity walls have insulated them, and that all homes have loft insulation and primary pipework insulation, based on a weighted average of solid wall and cavity homes (28:72) and 20% low energy lighting

Wood Fuelled Boiler

Pellet price of 5.03p/kWh and includes delivery on bulk (1 tonne) supply

Assumes wood fuelled boiler efficiency of 80% (from CERT)

You will not always see financial savings when replacing some fuels with wood fuel. This is because wood fuel is more expensive than other fossil fuels. However as wood fuel is almost carbon neutral, you can still greatly reduce the carbon footprint of your house.

Wood Burning Stove

No saving has been given, however we assume that a wood burning stove will typically provide 10% of space heating as specified in CERT.

Ground Source Heat Pump

Based on a GSHP Seasonal Efficiency Factor (SEF) of 2.24 for space heating delivered through radiators, and 1.52 for hot water.

Assumes hot water is preheated by heat pump and heated to full temperature by immersion heater (50:50)

Assumes property has been improved by: loft insulation and cavity wall insulation where applicable, primary pipework insulation and TRVs, it doesn't assume solid walls have been insulated.

Air Source Heat Pump

Based on an ASHP Seasonal Efficiency Factor (SEF) of 1.75 for space heating and 1.43 for hot water.

Assumes hot water is preheated by heat pump and heated to full temperature by immersion heater (50:50)

Assumes property has been improved by: loft insulation and cavity wall insulation where applicable, primary pipework insulation and TRVs, it doesn't assume solid walls have been insulated.

Solar Electricity

Savings assume 50% of the electricity generated is sold back to the grid and 50% is used on site.

It assumes a 2kWp system.

Solar Hot Water

Savings assume 50:50 split of evacuated tube/flat plate systems, with a collector area of 3.5m2.

Saving is assume the typical number of people in the house, based on the property type selected.

Wind Turbines

Assumes load factors taken from the Energy Saving Trust field trials in locations where wind speeds were 5m/s or higher.

Hydroelectricity

No savings have been given for hydroelectricity turbines as their performance is highly dependent on the water source and size of the system.