Gas engineer in front of Worcester Bosch hydrogen boiler

What’s next for boiler standards and efficiency?

The government has set out the likely next steps to improve boiler standards and efficiency, responding to the views given in its 2023 consultation.

The consultation looked at the controls used on domestic gas boilers, and whether combis should be able to modulate down their output. It proposed including system and regular boilers, as well as combis, and proposed increasing the minimum tested efficiency standards.

It also considered whether efficiency requirements should apply to boilers sized ≤45kW or ≤70kW; whether to require gas engineers to train in low-temperature heating system design; and how to ensure that heating systems are maintained.

Now, the government says it has reconsidered its proposals after feedback and made some changes:
• On controls, those in Classes I-III (simple controls) will no longer be sold from 2026.
• A mandate is likely that combi boilers and controls must use open protocols from 2026. If a new open protocol is not available, they will need to use OpenTherm.
• Boilers under 45kW should be capable of modulating their heat output down to 15 per cent of their maximum output without on/off cycling, while operating at least the same useful efficiency as when tested at part-load. This will take effect in 2028.
• Heating engineers will need to train in designing low-temperature systems.

The government has not yet set out how this training would be implemented – along with how to strengthen the maintenance of heating systems. It says it will with work with regulators such as HSE and the Building Safety Regulator to define an appropriate route.

It says it will use its upcoming consultation on ecodesign and energy labelling “to test regulatory amendments to implement these proposals”.

A decision on the role of hydrogen in home heating will come in 2026, with any requirement to make domestic gas boilers hydrogen-ready from 2030.

The government is proposing new minimum efficiency performance standards, encouraging greater use of the heat-pump element through price rebalancing and supporting the development of agile tariffs, as well as smart control standards.

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