What are sustainable alternatives to gas boilers?

What are sustainable alternatives to gas boilers?

Climate change and the UK’s quest to reach the magical ‘Carbon Net Zero’ by 2050 means the way we heat our homes is going to change.

It’s estimated that as many as 80% of all homes in the UK are heated using gas – but this is likely to change as soon as 2025 as the country moves at pace towards reducing its carbon emissions.

Replacing gas boilers with sustainable heating systems is very much on the agenda and here we’ll explain everything you need to know about the options available, the costs involved and the challenges that lie ahead…


Types of gas boiler

There are several different types of gas boiler found in UK homes.


1. Conventional boilers

Conventional, or heat-only boilers come with a cylinder and hot water tank.

Because water is stored in a tank, conventional boiler systems work best in larger homes as they can supply water to several rooms at one time.


2. System boilers

System boilers work in a similar way to conventional boilers, but don’t require a water tank.

They’re more economical than conventional boilers and the lack of a tank means they take up less space in smaller homes.


3. Combi boilers

Combination boilers control both the hot water and heating system in a home.

They heat hot water directly from the mains, so don’t require a cylinder or tank – cutting down on space.


What will happen to gas boilers in 2025?

Gas boilers will be banned from new-build homes in the UK from 2025.

It’s estimated around 160,000 new homes are built every year and from 2025, all of these will need to come with more sustainable heating systems in place.


Are combi boilers being phased out?

Combi boilers will no longer be installed in new-build homes from 2025 and will be replaced with low carbon heating systems.


Will the government make me get rid of my gas boiler?

The ban on gas boilers in 2025 only applies to new-build homes – so existing gas heating systems can remain in place.

However, it’s likely the UK will move towards replacing all gas boilers between 2025 and 2050, by which time the country is aiming to reduce its carbon emissions to net zero.

Incentives to switch to low carbon heating alternatives could come into play after 2025, with some already in place, such as the Renewable Heat Incentive which offers homeowners and landlords payments for installing sustainable heating systems.


What will replace gas boilers in 2025?

There are a number of renewable heating systems that will replace gas boilers in new-build homes from 2025 onwards.

These systems are already being installed in other homes across the UK…


1. Biomass boilers

Biomass boilers work in the same way as a traditional gas boiler.

But instead of burning gas, they burn biomass material – wood logs, chips or pellets.



Biomass boilers can cost between £4,000 and £21,000 for purchase and installation.



Biomass boilers only release the carbon absorbed by the wood during its lifetime, meaning they are classed as ‘carbon neutral’.

Biomass boilers also burn waste wood that would otherwise find itself in landfill.



Manual biomass boilers require regular refilling and although automatic options are available, ash from the wood burned needs to be regularly cleaned out of the system meaning they are a high-maintenance option.


2. Air source heat pumps

Air source heat pumps use the air from the outside to provide heating and hot water.

Some air source heat pumps provide heating through fans, while others provide heat through traditional water-filled radiators or under-floor pipes.



Air source heat pumps cost between £4,000 and £11,000 to purchase and install, while the cost of running one is electrical only.



Air source heat pumps use a 100% renewable source of energy, requiring only electricity to operate – making them a low carbon option. Many air source heat pumps can also provide cooling during the summer months.



Some air source heat pumps can be noisy, although advantages in technology are being made all the time. They also operate less well in lower temperatures, meaning homes that use them must be well insulated.


3. Ground source heat pumps

Ground source heat pumps pull the natural heat from underground and deliver it to the home.

Pipes are installed one or two metres underground and absorb the earth’s natural heat, pumping a warmed liquid into the pump where it’s heated further and then pushed around the property through radiators.



Ground source heat pumps cost between £8,000 and £12,000 to install, with electrical costs on top to run them.



Like air source heat pumps, ground source pumps are a low carbon option and provide a consistent level of heat from the ground for a very low running cost.



The efficiency of ground source heat pumps can be affected by soil types and they also require a large amount of space for installation, meaning they may not be suitable for all property types.


4. Solar panels

Solar thermal panels absorb heat from the sun and distribute that energy around the home as heat from radiators. Solar energy can also replace electricity and be used in conjunction with other sustainable heating solutions like ground and air source heat pumps.



The installation of solar thermal panels can cost between £3,000 and £5,000, but running costs are zero if used for both electricity and heating.



Solar is the most reliable form of renewable energy since the sun is always available. Solar panels also require very little maintenance, with cleaning once or twice a year all that’s required.



On cloudy days, solar panels are less efficient so a long run of dull days can influence the amount of heat produced by the system. Panels also require a great deal of space, so aren’t suitable for all types of property.


Eco friendly boilers

Most modern gas boilers are A-rated condensing models with superior energy efficiency and very little maintenance requirements.

Eco-boilers include combi options, heat-only models and oil boilers with lower emissions and high efficiency.

Although the move towards non-gas heating systems is set to gather pace in the coming decades, an eco-friendly gas boiler is a great option if your current boiler is old and inefficient.


The government ECO boiler scheme

Under the government’s Energy Companies Obligation (ECO) scheme, homeowners can apply for a grant to replace inefficient boilers with an eco-friendlier option.

There are certain criteria you’ll need to meet to qualify for the scheme and your boiler must be at least eight years old.


Further reading…