At Viessmann, we’re passionate about home heating and we realise that gas boilers are no longer the only heating option. If the UK aims to reach the goal of zero carbon emissions by 2050, we need to change more than just reducing the thermostat or washing our clothes at 30 degrees.

This is why we’re encouraging people to make the switch to low carbon heating, but what exactly are the types of low carbon heating and how can they reduce your carbon footprint?

Types of low carbon heating

If you’re wondering how you can heat your home and produce less carbon dioxide in doing so, you’re in the right place. Read on to discover the types of low carbon heating, and how much CO2 they could produce compared to your gas boiler. 

Air source heat pumps

  • Air source heat pumps are an excellent example of low carbon heating, because they take in natural heat from the air and use that to provide your home with hot water and warm radiators. Rather than burning a fuel source, such as gas or wood, they use electricity to increase the heat taken in from outside so it’s hot enough to heat your property
House heat demand
based on 4 bed detached home
Heater Heater efficiency Carbon emission factor Annual carbon emission Saving over gas boiler Saving over 10 years
kWh pa % kgCO2e/kWh kg kg tonnes
SAP 2012* 15000 Gas boiler 90% 0.216 3600 0 0
15000 ASHP 300% 0.519 2595 1005 10
15000 GSHP 400% 0.519 1946 1654 17
SAP 10+ 15000 Gas boiler 90% 0.210 3500 0 0
15000 ASHP 300% 0.136 680 2820 28
15000 GSHP 400% 0.136 510 2990 30

*SAP 2012 Standard Assessment Procedure (SAP) Methodology

+SAP 10 from June 2022

This a revised view of the carbon emissions from electricity due to reductions influenced by additional renewable generation methods like wind turbines and solar PV.

Air source heat pumps are becoming one of the most popular low-carbon heating methods. This is because they’re cheaper and easier to install than a ground source heat pump, which we’ll come onto next. 

Ground source heat pumps

Ground source heat pumps work in much the same way as their air source counterparts, but they take heat from the ground via a series of pipework instead of from the air. They also use electricity to generate further heat, meaning they will be about the same efficiency as an air source heat pump.

Even when these appliances take electricity from the National Grid, it’s thought that they still only use about 130 grams of CO2 per kilowatt hour (kWh) (reducing to 34 g/kWh when SAP10 is introduced) of delivered heat. A gas boiler uses approximately 215 grams of CO2 and an oil boiler, 320g.

Again, they can be powered by electricity gathered from solar panels, which would make their net carbon emissions absolutely zero. Both types of heat pumps work better in an efficient home, which means that you should aim to increase the insulation you currently have in your home. Not only could this further reduce carbon emissions but you’ll reduce heat loss and draughts.

Electric boilers

As with heat pumps, electric boilers could be a good way of reducing your home’s carbon footprint, but only if the electricity used to power the appliance has been created from renewable sources.

When electric boilers use a lot of electricity from the grid, the carbon emissions of your home could actually increase. This is because electricity is considered a ‘carbon-intensive fuel’. Heat pumps use a small amount of electricity, but an electric boiler is likely to use a larger amount.

These appliances work much like a giant kettle, in that they heat the water either to be used straight away or to be stored for later. To reduce the emissions produced from your electric boiler, you could consider joining a green energy tariff or having solar panels installed so you can generate your own electricity.

Solar thermal

Solar thermal is also sometimes known as solar water heating. Unlike traditional solar panels, which use sunlight to generate electricity, solar thermal systems use the sun’s natural heat to warm up water that is stored in a tank in the loft. This heat won’t be powerful enough during winter to get the water to the temperature you’d need to fill a bath or have a shower, but means that you’re putting less pressure on your other heating systems. During summer, you shouldn’t need any other appliances to heat your water.

The sun can naturally heat the water, which is then run through a conventional boiler or immersion heater to increase its temperature even further. Sunlight is a completely renewable resource, meaning you could see a reduction in your energy bills and you could also reduce your home’s carbon footprint.

This type of system will work best in homes that have a large surface area and that get the strongest sunlight for the majority of the day, such as south-facing properties.

If you’re serious about reducing your home’s emissions, the best solution may be to combine some of the heating systems we’ve mentioned. You can have both solar thermal and a heat pump, or a biomass boiler that heats one room while the rest of the house runs on a heat pump. Whichever method you choose, you know that you’ll be doing your bit for our planet.

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