Senior Lecturer, School of Engineering, University of Portsmouth

Jovana Radulovic does not work, consult, own shares, or obtain funds from any company or organization that will benefit from this article, and does not disclose any related affiliations other than academic appointments.

The University of Portsmouth provides funding as a member of The Conversation UK.

The British government recently announced new grants to encourage the public to switch from gas boilers to heat pumps, which is a more environmentally friendly energy alternative. But there are few claims about electric boilers as another low-carbon option.

The UK’s goal is to phase out gas-fired boilers and replace them with low-carbon technologies (such as heat pumps and electric boilers) in order to achieve a net zero carbon dioxide level by 2050. Families will receive grants of up to £5,000 for low-carbon heating systems, and the ambitious goal is to install 5.5 million heat pumps in the UK by 2030. There is currently no funding for electric boilers, but these also help small-sized households transition to low-carbon solutions.

In 2019, 1.7 million gas-fired boilers were installed in the UK, an increase of nearly 2% over 2018. Due to low initial and operating costs, gas boilers have long been the first choice of consumers. At present, 80% of households in the UK rely on gas for heating.

But electric boilers are very effective. All the electric energy they consume is converted into heat, while the thermal efficiency of gas boilers is only about 95%. They are also smaller than gas boilers and can be installed anywhere in the home without the need for a flue. Although electric boilers are not designed to meet the heating needs of larger homes, they are an ideal solution for apartments and small houses.

Read more: Should you buy a heat pump? This is how they compare with gas boilers

Although many people postpone heat pumps due to all the changes in needs, they may consider using electric boilers. In addition to the indoor unit and the hot water tank (sometimes two), the air energy heat pump also needs space to install the outdoor unit. Ground source heat pumps require more outdoor space, and they are usually more expensive. This will pose a challenge to many older and smaller families in the UK. There is also concern that the heat pump will cause additional noise.

Heat pumps are not a new technology. There are various models and sizes on the market. They are more efficient than gas boilers. They are designed to provide a stable temperature throughout the day, rather than using traditional gas and electric boilers "when needed." Heat pumps use electricity in a more efficient way. However, the investment cost of electric boilers is much lower because they are cheaper and simpler to install. Electric boilers rarely require any major construction work, such as installing new radiators and water storage tanks.

Since there are more lower-priced gas-fired boilers available on the market, electric boilers are rarely considered, and some consumers do not even know that they are an option. Denmark is a country that recognizes that electric boilers can be part of a green solution. In Denmark, heat pumps and electric boilers have become part of the decarbonization method of the heating network, and electricity is mainly derived from wind energy. Currently, Denmark relies on fossil fuels for approximately 40% of its energy, and the government’s goal is to be completely free of fossil fuels by 2050.

Historically, although studies have shown that the cost of electricity from renewable energy technologies (mainly wind and solar) is declining, the cost of electricity has made British households reluctant to choose any of them. In the past, generating electricity from renewable energy sources was more expensive than burning natural gas. With the improvement of efficiency and technology, the cost of renewable energy has dropped significantly in the past decade. As demand grows, prices will continue to fall.

Both heat pumps and electric boilers run on electricity. In addition to being generally more expensive than natural gas, some electricity still comes from carbon-intensive sources, making it less environmentally friendly. In the second quarter of 2021, due to unfavorable weather conditions and lower-than-expected sunlight and wind power, only 37.3% of electricity generation came from renewable energy sources. The electricity generated by fossil fuels is roughly the same, and the rest comes from nuclear energy.

In order to achieve the UK's net-zero electricity target by 2035, it is necessary to substantially increase renewable energy capacity while closing coal-fired power stations. Electricity is provided by renewable and low-carbon energy, and the combination of heat pumps and electric boilers for home heating and hot water production will meet our energy needs in a sustainable and climate-friendly way.

Although heat pumps and electric boilers are both effective solutions to combat carbon emissions, they are not the only technologies that increase the use of electricity.

As many technologies rely on electricity and there are more electric vehicles on the road, it is also crucial to expand electricity production capacity through renewable and sustainable energy.

Recently, electricity prices have fluctuated greatly, and rising energy prices are one of the main concerns of British consumers, especially those who are considering switching to electric heating. Although prices may soar in the near future, in the long run, the market should stabilize.

Reminding people to use green alternatives to heat pumps that do not involve large-scale interruptions and costs to heat their homes is likely to help achieve our future environmental goals.

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