Chris Stammers of BEAMA explains how hydronic (water-based) underfloor heating creates a unique sense of thermal comfort by combining even heat distribution with efficient heat transfer.

True thermal comfort is achieved when the indoor environment reduces the body’s need to work to stay warm or cool, ensuring anyone who’s enjoying the space feels neither too hot nor too cold. While comfort is subjective and can vary from person to person, designing a property that enables a consistently warm space benefits everyone.

Even heat distribution is essential and arguably the best system capable of warming all surfaces in a room uniformly is radiant heating, specifically hydronic (water-based) underfloor heating. Continuous loops of underfloor heating pipe, installed either within the screed or specialist panels under the floor, create a large radiant surface that heats the room from the floor upwards. This radiant heat warms both the objects and people in the space, creating immediate comfort rather than just heating the air.

Uneven temperatures can lead to problems for self-builders, such as condensation on cooler surfaces like walls or windows. This moisture encourages mould growth, reducing indoor air quality, while dust and allergens can collect in colder corners. While ventilation is essential for maintaining healthy indoor environments, keeping windows open during colder months isn’t always practical due to concerns about energy efficiency and security.

Underfloor heating spreads warmth evenly across the floor, maintaining a consistent ambient temperature and eliminating cold or hot spots. The gentle radiant heat it provides is frequently perceived as more comfortable than the convective heat emitted from conventional heating systems. Stable consistent temperatures also help regulate humidity, further improving indoor air quality and creating a genuinely comfortable living environment.

GETTING IN THE ZONE

Underfloor heating has evolved to meet modern building standards, and for self-builders, that means most systems must be zoned to comply with the Part L low-temperature update to the Building Regulations. While standard thermostats can meet the minimum requirements, attempting to control a whole property at a single temperature misses out on the energy saving potential of smart zoning.

Zoning gives self-builders the power to set different temperatures for each room, with personalised settings that can be adjusted and monitored via a thermostat or smartphone. Imagine keeping the living room and bathrooms cosy while the corridors and bedrooms are heated to lower temperatures. For larger homes, this not only maximises comfort but can also deliver significant energy savings.

Advanced systems can go even further with features such as adaptive start, which utilises local weather forecasts to activate the heating at just the right time, ensuring each space reaches the perfect temperature exactly when needed. By combining zoning with intelligent controls, underfloor heating doesn’t just keep a home thermally comfortable; it delivers smarter, more efficient comfort tailored to individual lifestyles.

PROVEN PERFORMANCE

With more challenging building targets and regulatory changes on the horizon, heat pumps have quickly become the leading low-carbon heating solution for new homes. To achieve their full potential, however, they need to be paired with heating systems designed for lower flow temperatures. This is where hydronic underfloor heating (UFH) truly shines. Thanks to its large surface area and compatibility with lower water temperatures, UFH is widely regarded as the most effective partner for heat pumps. Operating at flow temperatures typically between 35°C and 45°C, it allows heat pumps to run at their optimal efficiency, or Coefficient of Performance (COP).

To put this to the test, Energy House 2.0, a research facility at the University of Salford, compared the performance of different heating systems across an entire room. Among the factors assessed was spatial air temperature, which provides an accurate measure of comfort by revealing variations across the whole space, rather than relying on readings taken near a single thermostat or heat source.

The results were striking and UFH delivered the most even temperature profile, with virtually no variation across the room, compared to as much as 4°C with some systems and 2.2°C with traditional radiators. Performance improved even further when UFH ran continuously, rather than intermittently, underlining its real world efficiency.

Of course, comfort is about more than just average air temperature. How quickly a system warms up, how it behaves during off periods, and its running costs all shape the overall experience. A low running cost is less appealing if thermal comfort only arrives late in the evening.

The research shows that UFH strikes the best balance of comfort, consistency and efficiency. When viewed holistically, the cost difference compared to other heating options is relatively small. Additionally, because UFH is completely hidden within the floor, it allows complete freedom in interior layout and integrates seamlessly with almost any flooring material. In this way, underfloor heating delivers efficiency on two levels, providing true thermal comfort while maximising usable space.

Chris Stammers is portfolio manager at BEAMA’s Underfloor Heating Group