CO2 carbon savings of a heat pump and their environmental cost. (2024)

Written-by

Janet Richardson

Reviewed-by

Richard Burdett-Gardiner

Updated on

Sep 05, 2024

CO2 carbon savings of a heat pump and their environmental cost. (2024)

Heat Pump Manufacture

How much CO2 is produced in the manufacturing of a heat pump? 

Heat pumps, like renewable technologies, require energy for their production and raw materials to build them. They all have an initial ‘cost’ to our environment in their material extraction from the ground and the energy they consume during the manufacturing process. If the metals and refrigerant gas (working fluid) components within the heat pump itself are recycled correctly according to law at the end of its economic life, this should, for the large part, help to mitigate this initial environmental cost. (NB, compared to fossil fuel energy sources, it will have paid for itself many times over during its lifetime)

As there is currently little research into the exact CO2 and energy consumption figures generated/used during a pump’s manufacture, we can only provide you with an idea of the operating CO2 production and savings of heat pumps compared to other heating methods on the market.

Can Heat Pumps Reduce Environmental Pollution from Refrigerants?  

Not only do heat pumps use fewer refrigerants than air conditioning units and cooling systems but they use low-GWP (global warming potential) refrigerants. They have less of an impact on the environment than traditional refrigerants as they emit less harmful chemicals into the atmosphere. Most heat pumps use hydrofluorocarbons (HFCs), which have a GWP that is much lower than that of traditional refrigerants like chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).  

Most importantly though instead of depending on refrigerants to cool the air, heat pumps use a refrigerant to transfer heat from one location to another. This means that heat pumps use less refrigerants and that they can make a significant contribution to reducing environmental pollution from refrigerants. 

The GWP is a way of describing the relative global warming potential of refrigerants compared to CO2. Refrigerant circuits are usually airtight and do not need to be opened during the average life of a heating system. However, if refrigerants such as HFCs or perfluorocarbons (PFCs) are released into the environment through leaks or when disposing of old systems, they are far more harmful to the climate than CO2. 

Heat pumps are designed to prevent leaks, but older units can develop leaks over time. Refrigerant leaks will also reduce the efficiency of the heat pump causing it to use more electricity to heat or cool your home. Homeowners using heat pump systems are advised to have their heat pump serviced regularly to ensure all the parts are in working order and there are no refrigerant leaks. 

Though HFC refrigerants contain no chlorine atoms and so have no ozone-depleting potential (ODP), the release of HFCs into the atmosphere still represents a considerable danger to the environment as it is a notable source of greenhouse gases. While HFCs are not as bad as CFCs they are still 1,900 times worse for the environment when released than equal amounts of CO2.

Fluorinated hydrocarbons such as HFCs and PFCs are commonly used in heat pumps. These refrigerants usually contain R-134a, a hydrofluorocarbon, and are often used in air conditioning systems in buildings and vehicles. 

R-134a is a powerful greenhouse gas with a GWP (global warming potential) value of 1,430. In other words, the greenhouse effect of the R-134a refrigerant is 1,430 times the 100-year warming potential of the same volume of carbon dioxide.

In the future, the proportion of natural refrigerants used such as propane (R290), ammonia, and CO2 is set to increase with some manufacturers of heat pumps already using them. The aim is to reduce the potential harm caused by climate-damaging fluorinated refrigerants.

CO2 savings of heat pumps

Like all space heating technologies, it is advisable to mitigate against heat loss from the property in which it is installed, by insulating it as far as is practicable. This greatly assists the efficiency of the overall solution and decreases the amount of time the heat pump will be required to be operational, therefore reducing carbon emissions as well as saving you money on operating costs.

How much CO2 is saved by using a heat pump in the UK? 

As heat pumps require electricity to operate, they are not a completely carbon-free source of heating, but they are considered to be a form of low-carbon heating.  

Heat pumps work by drawing heat from the natural environment and using electricity to transfer that heat to your home's heating system.  The higher the COP (coefficient of performance) of your heat pump, the more energy you will extract from the air, water, or ground per unit of electricity used to operate the pump.

Heat pumps operate at very high efficiencies of around 400%, which means that for every unit of electricity used, 4 units of thermal energy are created.

Although heat pump systems do not burn fossil fuels, they run on electricity, and as not all electricity generated in the UK comes from renewable sources heat pumps still account, indirectly for some carbon emissions. 

If you have solar panels, some of the electricity needed to power your heat pump can come from your panels rather than the National Grid. Alternatively, you can switch to a genuine renewable energy supplier to make sure your heat pump is powered by 100% renewable electricity from British generators. 

Fortunately, heat pumps don’t need to use a lot of electricity as a heat pump’s efficiency is about three times that of a traditional oil or gas boiler. This means that they use about three times less energy to generate the same amount of heat making them one of the most environmentally friendly forms of heating available.

According to research by British Gas, if a UK household with an average annual energy consumption of 12,000 kWh (a two to three-bedroom house) switches from a mains gas heating system to a heat pump a household’s emissions can be reduced by 1,404 kilograms of CO2  annually which is equivalent to the emissions released by driving 4,544 miles in a typical petrol car. 

Annual emissions can be even less than this. Air-source heat pumps produce 850kg of CO2 per year compared to gas boilers which produce 2,500 kg of CO2 .

The amount of CO2 saved will depend on how much energy you use, the type of heating system you’re switching from (gas, oil, LPG, electric), the efficiency of your old system, and that of your new heat pump.  

Oil boilers generate more carbon emissions than almost any other type of home heating. An average home using oil as a fuel source results in carbon emissions of 5,200 kg per year. That’s more than two return flights from London to New York. You also have to add in the added environmental impact of delivering the oil by truck.

Currently, household heating is responsible for nearly a third of the UK’s annual CO2  emissions which British Gas has calculated to be as much as all petrol and diesel cars CO2 emissions combined.

British Gas derived its research findings by using the average energy usage for space heating and hot water in homes of various sizes, according to the Office of Gas and Electricity Markets’ (Ofgem) analysis, and the emission efficiency ratios (CO2 per kWh delivered) of different heating systems such as LPG, Oil, Mains Gas, and Direct Electric according to the Energy Performance Validation Scheme. Using this information, British Gas was able to calculate a household’s annual CO2 emissions generated for home heating and hot water. 

British Gas then compared this value against the CO2 emissions by the same property type with an air source heat pump (ASHP) heating system. By calculating the difference between the two final values, British Gas was able to see the amount of CO2 that could be saved by switching to an air-source heat pump. 

Opinions differ on the amount of CO¬2  savings that can be made. For instance, the Energy Saving Trust has calculated that the average three-bedroom home will save 1,900 kg a year with a heat pump compared to a new gas boiler, and 2,900 kg compared to an old gas boiler.

The UK could save around 54 million tonnes of CO2 a year if every one of the 28.2 million households in the UK had a heat pump instead of a gas boiler, This would reduce the UK’s annual CO2 emissions of 330 million tonnes of CO2 by 16%.   

Most of the remainder of the UK’s emissions come from industrial work, transport, and imports and exports.  You also need to take into account that not all UK households use a gas boiler to heat their homes. Approximately 3% of households in England and Wales use oil boilers, for example, which have higher emissions than gas boilers and we mustn’t forget those households who have already switched to heat pumps. 

Other environmental issues 

It is also worth noting that, unlike other more conspicuous renewable energy technologies, heat pumps have little impact on the surrounding area. One potential issue, however, is that they can tend to create some noise. It is for this reason that obtaining planning permission may be necessary (more on this here). The level of noise emitted by systems varies dramatically, however, so it is necessary to check with manufacturers. Some are now ‘whisper quiet’. 

If you’re worried about noise pollution, ductless heat pumps can provide the same energy efficiency and heating and cooling without any of the extra noise. They are also smaller than traditional heat pumps so take up less space and are ideal for homes that have limited space.