Martyn Bridges of Worcester Bosch, on behalf of the Hot Water Association (HWA), discusses how the latest proposed Building Regulations may affect hot water cylinders.

On 19 January, the Ministry of Housing, Communities and Local Government published a summary of six sets of responses to Building Regulations and new homes built from 2024/25. 

Its approach has been more collaborative than in the past, as there has been a second round of consultations to collect wider industry input. Currently nearing the final version, it is very positive to see the more industry feedback reflected in these important documents. 

As with most regulations, they will have some sort of effect on many technologies, products and industries, even if this is not instantly obvious. Heat pumps and boilers are the main topic of conversation when discussing heating regulation, however hot water cylinders, as well as radiators and pipework, are also something that should, and are being considered.

Immediate steps

The most imminent section for installers is Part L in existing buildings. Firstly, the energy efficiency requirements of gas boilers will remain the same as they were increased to 92% in 2018, but the efficiency requirement of oil boilers has been increased to 91% – there will be work required to meet this target.

Due to the projected increased uptake of heat pumps, the regulations call for a minimum Seasonal Co-efficiency of Performance (SCOP) figure of three for heating and two for domestic hot water for heat pumps being installed into existing homes. 

This has not regularly been achieved in the past, so installers will need to look closely at the existing heating system to see if it is sized sufficiently, while also considering other elements such as where a hot water cylinder may be able to fit in the property.

Another new requirement is when an entirely new central heating system is replaced, the new system must be designed to run at 55°C to ensure that the house is ready for future heating technology. This would make the home suitable for a heat pump as the radiators and pipework would be sufficiently sized. 

There is still an argument, however, that perhaps instead of forcing the new technology into existing homes, we should look to less disruptive applications for a place to put heat pumps.

Learning from the past

There was some excitement when the Department for Business, Energy and Industrial Strategy announced a trial to install 750 heat pumps into existing properties that had a boiler-fed system. It was planned that 85% would displace a gas-fired boiler system and the remaining 15%, for homes with an oil or LPG boiler.

There was initial interest, with over 4,500 applications made for what was a ‘free of charge’ heat pump installation. This would cover all work required to the house and heating system to be adapted for a heat pump. However, for varied reasons only 19 installations had been completed by the end of November 2020. Some homeowners didn’t want to progress because of COVID-19 reasons, some didn’t expect the amount of remedial work required to facilitate a heat pump installation, and others just chose not to at this moment in time.

There were many technical reasons why homeowners didn’t progress with a heat pump installation, existing radiators not being large enough, existing pipework insufficient in diameter for the increased velocity that a heat pump operates at, and also the proliferation of combi boiler installs.

A better place for heat pumps may well be newbuild homes or large renovations rather than boiler replacements. The property can be specified and built with heat pumps in mind at the outset. So, space can be provided for a hot water cylinder and sometimes a buffer tank, which are required in a heat pump-powered heating system. Also, radiators and pipework can be specified and fitted at the correct sizing and material to support an efficient heat pump.

This has certainly been confirmed by the recently published second consultation to the Building Regulations. Within this, the Future Homes Standard has been put together in such a way that makes it almost impossible to fit a fossil-fuelled heating source into newbuilds from 2025 onwards. This means that heat pumps and hot water cylinders will certainly be the way forward for this area, which is a comforting reassurance for manufacturers of both technologies.

With this in mind, hot water storage cylinders will become more prominent in customer requirements, as well as merchant stores. However, the cylinder mix that merchants sell today will change, the amount of heat pump compatible cylinders is going to grow considerably from the relatively small amount of sales today.