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What will replace gas boilers?


Jo Alsop

Heating Hero

The Heating Hub

What is the lifespan of a gas boiler, Jo Alsop reviews the future of domestic heat


How will we heat our homes in the future?

The Government's recently released Heat and Building Strategy Energy has confirmed the phase out date for gas boiler in existing homes is 2035 however this date was recently dropped by Government*. Gas boilers will be banned in new build homes from 2025.

The new UK energy map

There is no one perfect replacement for gas boilers and no simple way of weaning ourselves of this cheap, easy and compact heat source. 

The future of heating for you will come down to what type of property you are living in (see section 3 for timeline scenarios), however it will also be determined by where you live. The UK will be a patchwork of renewable energy technologies that will vary depending on your location. This much we know:

  • 80% of homes will move to an air source heat pump. This will be mostly houses with gardens.
  • If you live in a densely populated urban area you may get your heat from a local 'heat networks' whereby low carbon heat sources serve a 'zone'.
  • Off grid homes may use 'green gas' such biomethane from food waste.
  • In the very long term, you might form part of a 'hydrogen hub' and your heating system will run on hydrogen gas, but as it stands today 56 independent reports have said there is little to no role for hydrogen in home heating.

WARNING: Gas boilers will NOT be banned 2025 for existing homes - The recent IEA report (International Energy Agency) published in May 21 was a cautionary piece on the need to remove gas boilers by 2025 if we are to meet our net zero targets. The report made big headlines and has caused a great deal of confusion amongst households. To be clear, it is not the stated intention of the UK government to ban gas boilers for existing households in 2025. Consumers have reported receiving sales calls pushing for heat pump installations on the basis that gas boilers will be banned in 2025. These claims are completely false and must be ignored. If you are concerned about a call you have received please contact us.

Proposed technologies:

Heat pumps will be the main heat source for UK homes, however there are a few other technologies in the mix:

Hydrogen boilers

Hydrogen boilers don't exist, nor do hydrogen-ready boilers. Hydrogen may be blended into our gas supplies at some point, but your existing boiler will not require replacement or modification.

Air source heat pumps

Air source heat pumps are air conditioning units in reverse, the same as fridges. They take latent heat from the air and compress it to raise its temperature. This heat is transferred to a chemical called a refrigerant which - via a heat exchanger - will heat your radiator/UFH water.

Heat pumps run on electricity, but if set up correctly can generate 3-4 units of heat energy for every one unit of electricity. As more of our electricity is generated by renewable processes, such as wind farms, so heat pumps offer the biggest leap to reducing greenhouses gases from our homes.

They are not without their drawbacks however. The external unit is large and we are likely to have to give up our airing cupboards again to a large hot water cylinder. As such they are not currently that suited to small homes, although the roof space is an option.

Modern heat pumps can run at high temperatures as standard however which means radiators do not necessarily need changing, but swapping a few might improve efficiency significantly.

The Committee for Climate Change state that 5.5 million heat pumps need to be fitted this decade, around 2.2 million will go into new build homes and 1 million into off-grid homes. For more on heat pumps see our ultimate guide to air source heat pumps.

Biomethane 'green gas' from anaerobic digestion

This is gas produced from food waste and the Government view this as potentially playing a vital roll in hard to heat homes off the gas grid. It can be injected into the gas grid or delivered by canisters (LPG bottles and bulk storage). However it cannot be produced on a sufficient scale to replace all of our existing gas supplies.

Solar panels

Solar thermal panels (that heat hot water) are by far the most efficient energy source available. Via pipes in the panel, the sun heats water that is pumped through the pipes and directly transferred to heat water and/or radiators if set up to do so. However this is energy that cannot be stored, i.e. if you are at capacity for hot water then the panels will 'stagnate'. Solar panels work best when combined with other renewable sources.

Solar PV panels (stands for photo-voltaic) produce electricity. They are much less efficient, however households can harness electricity all year round for appliances that are always on (for example fridges) and with battery storage can store surplus electricity for when it is needed.

For smaller homes, once retrofitted, it may be possible to use a combination of solar thermal and PV panels, with back up immersion, to provide enough energy to heat our homes. For larger homes they can form part of a mix of renewable sources that offer different benefits at different times of the year.

Hybrid heat pumps

Hybrid heat pumps combine a fossil fuel boilers (oil or gas) with a low temperature air source heat pump. The gas or oil boiler is used to top up the low temperatures supplied by heat pumps to meet the heating demands of the home where a heat pump cannot do it alone. With the advert of higher temperature heat pumps as standard however, hybrids are less relevant. The are still necessary for properties with a kW power demand higher than 15kW. For more see our Guide to hybrid heating.

Heat networks

According to the Heat and Buildings Strategy, heat networks will be a key technology for high density heat demand, such as city centres. Large, low carbon heat sources have the potential to serve urban 'zones'. This removes the need for bulky equipment in flats for example and instead a boiler sized unit is fitted housing a heat exchanger to turn the common low carbon heat source into heat for the home.

Battery storage

Batteries are already in regular use with solar PV arrays and new products are coming on line to provide heating to wet systems (radiators and underfloor heating heating). Batteries can store energy from a solar PV array or from cheap overnight electricity (from wind turbines for example) for households to use in the daytime. This reduces the cost of electric and spreads the demand over 24 hours. These could be excellent boiler replacements but do rely on overnight tariffs to run affordably.


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*ENERGY WHITE PAPER - Heat and Building Strategy - View Heat and Buildings Strategy