Chris Stammers of the BEAMA’s Underfloor Heating Group explores the key benefits and latest research around low temperature heat emitters, and how they can support specification choices that futureproof residential projects.
With the Future Homes and Buildings Standard (FHS) due to come into effect soon, architects working on residential dwellings are under growing pressure to design heating systems that are not only energy efficient, but which are also compliant with increasingly stringent regulations. One of the most effective ways to meet these low-carbon objectives, whether in new-build housing or large-scale refurbishments, is by integrating underfloor heating (UFH) with air source heat pumps (ASHP).
As of June 2022, the revised Part L of the Building Regulations has placed firm requirements on all new residential buildings to reduce carbon emissions by at least 31% compared to the previous benchmark. This also applies to extensions and significant renovations under Part L1B. Central to these regulations is the move towards low-temperature heating systems, now capped at a maximum flow temperature of 55°C. Designers must also provide a Building Regulations England Part L (BREL) report with photographic evidence demonstrating compliance, underlining the need for thorough planning.
A natural fit: UFH & ASHP
ASHPs are fast becoming the preferred low-carbon heat source for UK homes, particularly when integrated into well-designed UFH systems. The compatibility is straightforward: UFH systems operate efficiently at lower flow temperatures, often as low as 35°C, which supports ASHP in achieving a higher Coefficient of Performance (CoP), maximising energy efficiency and cost savings. Compared to radiator-based fossil-fuelled systems, the combination of ASHP and UFH can deliver much greater efficiency, making it a key strategy for net zero building targets.
Recent research from Salford University’s Energy House 2.0 project demonstrated that hydronic underfloor heating excels at maintaining consistent temperatures throughout each zone. The study recorded minimal temperature variation, only 0.8°C at -5°C and 0.7°C at +5°C when operated using a standard SAP heating pattern. Traditional radiators showed a minimum variation of 2.2°C, while other systems displayed differences of up to 4°C. Even greater consistency was achieved when UFH was running continuously.
These results also emphasise UFH’s advantage when combined with air source heat pumps, delivering efficient, evenly distributed heat throughout the home. The low temperature radiant heating method boosts energy performance, enhances long-term occupant comfort, and assists in meeting low-carbon building standards.
Designing for retrofit readiness
While new-build projects offer a ‘clean slate,’ architects must also consider how heating systems can be retrofitted to accommodate heat pump technology in existing homes. This is where UFH provides a major advantage. A well-designed UFH system with appropriately spaced pipe centres and increased pipe diameters (e.g. 17 mm over 12 mm) can futureproof a property for a heat pump upgrade, ensuring optimal output at lower temperatures.
Low-profile systems offer a practical solution for retrofits or extensions where screeded systems aren’t feasible. These systems allow minimal floor build-up, often less than 20 mm, making them ideal for older properties where ceiling heights or door thresholds are a constraint.
Going beyond completion
While operational efficiency is a cornerstone of regulatory compliance, embodied carbon is increasingly part of the sustainability conversation. According to Government-backed studies, modern UFH systems have a significantly lower embodied carbon footprint than radiator systems, up to 93% less. PE-RT (polyethylene of raised temperature resistance) pipe used in many UFH systems has a long lifespan. It can be safely recycled, making it both durable and environmentally responsible.
Partnering for performance & comfort
Precision system design is essential to ensure that UFH systems deliver the required heat output while meeting project-specific criteria. Working with a reputable supplier that can support CAD layouts, heat loss and heat output calculations, controls integration, and commissioning advice is crucial. This ensures that all elements, from flow temperatures to zoning, are designed with compliance and long-term performance in mind.
Radiant heat from UFH supports energy performance and enhances indoor air quality and occupant wellbeing. Unlike convected heat from traditional systems, which can stir up dust and allergens, UFH delivers even warmth across the entire floor surface with minimal air movement. This reduces the spread of airborne particles and can help lessen symptoms for allergy and asthma sufferers. It also provides a more consistent thermal gradient, with the warmest temperatures at floor level, exactly where it’s needed most.
In a fast-changing regulatory landscape, architects must specify heating systems that offer end users efficiency and comfort in equal measure. Underfloor heating is proven to strike that balance, particularly when paired with ASHPs. It offers a versatile, design-led solution that aligns with the UK’s roadmap to net zero and elevates the standard of living in every project.
Chris Stammers is portfolio manager for BEAMA’s Underfloor Heating (UFH) Group