Navigating the transition: traditional to low-temperature heating systems

From meeting new regulatory requirements and safeguarding homeowner energy bills, there’s much to consider when specifying a heating system. Here, Laurie Michel, Pre-Contracts Director at WMS, provides advice on transitioning from traditional to low-temperature heating systems and explains why hydronic (water-based) underfloor heating is the leading solution for new builds and major refurbishments.

A time for change

“The Government’s interim revisions to Part L for the Future Homes Standard – the update to the Building Regulations and Part L – came into force in June 2022 and signified a huge shift in how new home heating systems are designed.

“Today, the heating system within any newly built home or property undergoing major refurbishment must demonstrate a maximum flow temperature of 55˚C. Traditional radiators are becoming a much less viable option to meet this requirement. They’d need to increase even further in size to meet the new regs, increasing upfront costs and creating interior design headaches by taking up even more wall space.”

Radiating low-temperature benefits

“Hydronic (water-based) underfloor heating has always been, by its very nature, a low-temperature system, dating back to Roman times, and is the ideal solution to meet the revised regulations. It covers a much greater surface area than radiators and is designed to run at low temperatures (35°C rather than the 70°C of a typical radiator system). Underfloor heating systems can also be fully zoned, ticking a crucial regulatory box and ensuring no energy is wasted.

“As less heat is being used, underfloor heating can be up to 15-40% more efficient than an equivalent radiator system, especially when placed into a very well-insulated new build environment and zoned/controlled correctly. The low temperatures achieved are desirable from an energy bill perspective and are now a regulatory requirement.”

Fully future proof

“The Government expects heat pumps will be the primary heating technology for new homes to ensure they meet the needs of zero carbon emission homes and maximise efficiency for the low water temperature update to the Building Regulations and Part L.

“However, for ASHPs to achieve their most effective coefficient of performance (COP) level, they need to run between 35-45°C – this is something water-based underfloor heating can easily achieve, making it the ideal technology partner.

“By switching to underfloor heating, there’s also a 93% reduction in embedded carbon in a dwelling compared to radiators. Importantly, this calculation considers material volume, product lifespan and the manufacturing process.”

Supports site coordination and timelines

“Incorporating underfloor heating into the construction process is also very straightforward. Depending on construction preferences, there’s flexibility to choose between integrating it during the oversite or weathertight stages, making it an ideal choice for seamless site coordination.

“There is also a time-saving factor to consider. Our study, conducted on 100 units to compare installation durations between underfloor heating and radiators, revealed that underfloor heating was 15% faster to install. This makes it a prime choice to keep projects on time and budget.”

Maximises useable living spaces

“Radiators can be large and will only get larger now due to lower temperature requirements, which means they’ll take up even more valuable wall space within a dwelling.

“In contrast, underfloor heating offers complete freedom in design and build choices, making it easier to incorporate features like floor-to-ceiling windows to flood rooms with natural light. There is also the chance to create open-plan spaces as underfloor heating is discreetly installed under the floor.”

Longevity and low maintenance 

“Typically, traditional radiators require an annual check for air in the system/bleeding and may frequently need a more extensive inhibitor dosing. In addition to this ongoing maintenance, they typically need to be replaced every 25 years, making the product’s lifespan relatively short.

“In contrast, underfloor heating systems require very little maintenance and can last three times longer, with most offering at least a 75-year guarantee, providing additional reassurance that it will likely outlive the lifetime of the building. Good quality underfloor heating pipe, made from superior quality, five-layer, sustainable PERT (polyethylene of raised temperature resistance), can also be melted down safely and reused, offering a sustainable solution throughout the product’s life cycle.”