Heat pump vs gas boiler comparison

As concerns and media coverage about climate change continue to grow, the use of fossil fuels in heating our homes is becoming increasingly scrutinised. In this post, we will compare air source heat pumps to gas boilers in terms of their efficiencies, running costs, and CO2 emissions.

Heat pump vs gas boilers efficiencies

Efficiencies: Air source heat pumps are much more efficient than gas boilers. While the efficiency of a modern gas boiler typically ranges from 95-98%, the efficiency of a heat pump is typically around 300-400%. This means that for every unit of electricity used to power the heat pump, it can produce up to 4 units of heat.

The below diagram illustrates the differences in efficiencies visually, with electric heaters also included for comparison.

Heat Pump vs Gas Boilers- Running Costs

Historically, heat pumps were more expensive to run than gas fired boilers. But with recent changes to energy costs, electricity is now down to only around 3.5 times more expensive than gas. This means they now share similar running costs with gas fired boilers, with the most efficient heat pumps being slightly marginally cheaper to run. The below diagram shows the running costs comparison visually with electric heaters also thrown in for perspective.

Heat Pumps vs Gas Boilers- Carbon Dioxide Emissions

CO2 Emissions: When it comes to CO2 emissions, air source heat pumps are a much greener option than gas boilers. This is why the use of them is currently being pushed by the government, with incentives such as the ‘Boiler Upgrade Scheme’. The CO2 factors (government-DEFRA figures) used, to calculate the carbon dioxide emissions, change over time with factors such as the electricity grid becoming ‘cleaner’ with the recent expansions in wind and solar generation.

The below diagram gives a visual representation of carbon emissions for equal quantities of heat energy produced by gas boilers, heat pumps and standard electric heaters.

For further heat pump information see What is a heat pump post. Although heat pumps can contribute to lower heating bills, there are significant outlay costs which need to be considered carefully. There are also design considerations associated with the lower operating temperatures of high-efficiency heat pumps, which mean they are not suitable for all properties. See the Building Services Portal Heat Pump assessment calculator for further advice and easy to use selection guide. It also contains high-level costs advice and information relating to the Government funding available through the boiler upgrade scheme.

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