What sort of savings could be made by switching to an Air-to-air heatpump?

As part of the drive to lower CO2 levels being emitted by humanity, we are always looking for new solutions to heating our home. Heatpumps are lauded as a measure to both lower CO2 emissions and save money. We compare heatpumps to other common forms of heating using current (09/2022) rates and technologies.

Energy costs and CO2 usage

The savings compared to a modern 90% efficient gas boiler are marginal. The true cost saving benefit comes when you install systems into properties using non-gas heating. The CO2 savings are clear across the board. To put things into perspective a UK car puts out on average 221.4 grams per mile, 10,000 miles a year emitting 2,214kg of CO2.

It may seem counterintuitive that gas boilers emit less CO2 than electric radiators. This is because much of our electricity comes from Natural Gas and other unsustainable sources, the grid also loses energy transforming power to get to your home.

Cost of install

An air-to-air system install will cost £1,000-£6,000 depending on the size of the property. These work like traditional air conditioning units so cannot use existing radiators, but the price includes a replacement heater inside. For houses running on electric only heating, these are a very good way to heat your home and can often pay for themselves within a year or two.

Gas
We used a modern gas boiler with an efficiency of 90%. As boilers get older, their efficiency will diminish.
We used a gas rate of 10p, this is the current price cap (12/2022).
Bulb published data indicating that gas has a CO2 output of 0.184kg/kw

Oil
We used a modern 90% efficient oil burner.
Heating oil contains 10.35kw/L.
Current rates for heating oil are around £0.9298 per L (12/2022).
The factor assumed for heating oil is 2.96 kg of CO2 per L burned.

Electric heating
Electric heating is assumed to be 100% efficient.
We used the current price cap for electricity, 34p per kWh.
Bulb published data indicating that electricity has a CO2 output of 0.233kg per kWh.

Storage heaters
The same efficiency and CO2 is assumed as electric heaters but with an economy 7 rate of 20.37p per kWh

Air source heat pump
The same rate and CO2 is assumed as electric heaters, but with an efficiency of 440%. 440% is a typical Seasonal Co-efficient of Power for a unit, different models vary, some are as high as 574% efficient, others 372% efficient, measures taken at 20 C indoor (CDB) 6 C outdoor (CDB).