UK consultation targets improved boiler efficiency standards

Feedback is now being sought on proposals designed to reduce ‘oversizing’ of domestic combi boilers and also setting out new requirements for controls

A new government consultation has been launched with the aim to ramp up the efficiency of boilers sold in the UK. The proposals contained within the consultation would apply to all future sales of domestic boilers and be introduced in parallel with efforts to scale up the use of heat pumps and low carbon heat networks.

A major aim of the proposed changes is to ensure all new boilers are not overpowered for domestic needs and can run at an optimal performance to reduce energy demand in homes. If approved, these reforms would apply to both natural gas and hydrogen systems.

Feedback is being sought for the proposals in the ‘Improving Boiler Standards and Efficiency’ consultation until 21 March 2023. The consultation claims that the proposals could see a six per cent improvement in the in-home performance of new boilers that would be equivalent to a £30 on annual energy bills each year for the average household.

These reform proposals include provisions to revise control requirements for boilers. This would ensure a boiler system is communicating with its controls to modulate heat output and deliver lower flow temperatures, the document added.

The consultation seeks to tackle the issue of oversized combi boilers by better allowing them to modulate performance in line with seasonal heating needs of a property. Another aim is to improve heating system design and maintenance to ensure that the efficient operating of a boiler is being maintained over its lifetime.

The consultation cited research from government departments such as BEIS, feedback from the review of the Boiler Plus regulations, as well as the recently updated Building Regulations.

It said that natural gas boilers were commonly running inefficiently compared to what is required to heat many UK properties based on the average external temperature.

The consultation stated: “Traditionally, central heating systems have been designed to operate at flow and return temperatures of 80 deg C to 60 deg C. However, these high flow temperatures would only be required when outside temperatures are very cold, sustained at sub-zero levels of approximately -2 deg C or -3 deg C.”

“BEIS research found that around 50 per cent of homes have heat emitters adequately sized to provide thermal comfort at a flow temperature of 55 deg C on an average winter day, with outside temperatures at around 4 deg C.”

A major conclusion of the findings was that further changes in efficiency standards for boilers would provide a “significant opportunity” to cut energy demand without impacting warmth in homes for the majority of the year.

The future for UK boiler use

The scope of the consultation is focused mainly on natural gas boilers designed for domestic use with a capacity of 45 kW or less. However, respondents are also asked if they would back extending the requirements to large scale boilers with outputs of up to 70 kW that would include non-domestic use.

The consultation added that the proposals were expected to apply to existing homes already on the gas grid. This was because the planned introduction of a Future Homes Standard for new build properties in 2025 is expected to require low carbon systems such as heat pumps and heat networks to become the primary technologies used.

However, the consultation concluded that some form of domestic gas boilers would continue to be needed to be installed in the immediate future. This would make it imperative to ensure further efficiency improvements in system design and how boilers are controlled as part of an ongoing strategy to decarbonise the housing stock, the government added.

It stated: “Each year up to 1.7 million domestic-scale natural gas boilers are installed in the UK. Even with increasing heat pump deployment, we expect a minimum of 10 million further domestic gas boiler installations between 2025 and 2035.”

The consultation also seeks feedback around the consideration for making use of hydrogen boilers and the potential for scaling up use of hybrid systems that could combine some form of gas heating with heat pumps.