UPDATED Clean Heat Market Mechanism (CHMM) 2025

What is the CHMM?

The Clean Heat Market Mechanism (CHMM) is a UK Government initiative designed to drive the adoption of low-carbon heating systems, such as air source and ground source heat pumps, by requiring boiler manufacturers to increase their share of heat pump sales.

Originally set to launch in April 2024, the CHMM was delayed by a year to allow the industry more time to adjust and to prevent unfair price increases for consumers. The scheme now launches in April 2025, with an updated starting target of 6% of total boiler sales coming from heat pumps in the first year (2025/26).

The CHMM is part of the government’s wider plan to:

• Reduce carbon emissions from home heating

• Increase the availability and affordability of heat pumps

• Support the UK’s goal of net-zero emissions by 2050

• Achieve the target of 600,000 heat pump installations per year by 2028

For homeowners, this means more choice, better availability, and potentially lower prices on heat pump installations in the coming years.

Why Was the CHMM Delayed?

The CHMM was originally scheduled to begin in April 2024, with an initial target of 4% of manufacturers’ boiler sales needing to come from heat pumps. However, in early 2024, concerns were raised about rising gas boiler prices, with some manufacturers blaming a “boiler tax” linked to the CHMM.

After further investigation, it was found that these price increases were business decisions made by manufacturers, not a direct result of the CHMM itself. However, to avoid unnecessary cost increases for consumers, the government decided to postpone the CHMM by a year.

As a result:

• The CHMM now starts in April 2025

• The initial sales target has been raised to 6% in the first year (instead of 4%)

• The policy remains unchanged in its goal to increase the adoption of heat pumps across the UK

This delay gives manufacturers more time to prepare, while still keeping the government’s long-term decarbonisation targets on track.

How Does the CHMM Work?

The Clean Heat Market Mechanism creates a legal requirement for boiler manufacturers to increase their share of heat pump sales each year.

Under the updated 2025 rollout:

• Boiler manufacturers must ensure that at least 6% of their total UK sales come from heat pumps in 2025/26

• This percentage is expected to increase annually in the coming years

• Manufacturers who fail to meet targets will face financial penalties, incentivising them to make heat pumps more accessible and affordable

This means consumers can expect a growing range of heat pump options, along with potential price reductions as competition increases in the market.

Will Boiler Prices Increase in 2025?

Many homeowners have been concerned about rising gas boiler prices in connection with the CHMM. Some manufacturers, including Worcester Bosch, Baxi, and Vaillant, raised prices on certain models by up to £120 per unit from January 2024 onwards.

However, it’s important to note:

New boiler cost still is far lower than the heat pump equivalent and will continue to be so, also many modern boilers are extremely efficient.

• The CHMM itself does not impose a direct tax on boilers

• The government has not mandated price increases

• Price changes are set by individual manufacturers, not government policy

Government Grants and Financial Support

Although the CHMM does not provide direct financial incentives, government grants and schemes are available to help homeowners switch to heat pumps.

Boiler Upgrade Scheme (BUS) – £7,500 Grants Available

The Boiler Upgrade Scheme (BUS) continues to offer grants of up to £7,500 towards the installation of an air source or ground source heat pump.

Who qualifies?

Homeowners in England and Wales upgrading from fossil fuel boilers

How much?

£7,500 towards a heat pump installation

How to apply?

Through an accredited MCS-certified installer

This significantly reduces the upfront cost of switching to a heat pump, making it a more viable option for those considering a heating upgrade.

How Will the CHMM Impact Heat Pump Availability?

As the CHMM pushes boiler manufacturers to increase their heat pump sales, major brands like Vaillant, Worcester Bosch, and Baxi are already expanding their heat pump ranges.

Consumers can expect to see:

• More models available as manufacturers meet CHMM targets

• Hybrid heat pumps (which combine a gas boiler with a heat pump) becoming a more popular option

• Lower prices over time as supply increases and technology improves

If you’re considering switching, now is a great time to explore your options and see if a heat pump could work for your home.

What About Existing Gas Boilers?

If you already have a gas boiler, you are not required to switch. Gas boilers are not being banned, and you can still replace an older model with a new boiler.

However, with policies like the CHMM and increasing government incentives, heat pumps are expected to become the more cost-effective choice in the near future.

Key Considerations for Homeowners

• If your boiler is over 10 years old, switching to a heat pump could save you money in the long run

• New gas boilers are still available, but government policies may make heat pumps the better long-term investment

• Government grants and finance options are available to help offset the cost of switching

is Now the Right Time to Switch to a Heat Pump?

With the CHMM launching in April 2025, the UK is moving towards a future of cleaner, more efficient heating. While the transition will take time, heat pump prices are expected to fall as manufacturers increase production and technology improves.

If you're considering making the switch:

• Check your eligibility for the £7,500 Boiler Upgrade Scheme grant

• Compare heat pump running costs vs. gas boiler costs

• Speak to a heating professional for personalised advice on what’s best for your home

Thinking about upgrading your heating system? Get a quote today and explore whether a heat pump or a new energy-efficient boiler is right for you.

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