Ashley Cooper of WMS explores how underfloor heating provides the ideal balance between indoor air quality, comfort and efficiency.

When planning a self-build, comfort and efficiency are often top priorities, but one crucial factor is sometimes overlooked – indoor air quality. One leading solution to create a healthy indoor environment is hydronic (water-based) underfloor heating, thanks to its ability to minimise airborne particles, reduce humidity-related issues and create consistently comfortable air temperatures. 

AN ALL-ROUND SOLUTION

With modern homes designed to be more airtight and well-insulated to meet Building Regulations, it’s essential to ensure fresh, clean air within the living environment. As self-builders strive to create energy-efficient and comfortable homes, indoor air quality (IAQ) must become an increasingly important consideration.

Poor IAQ can lead to respiratory issues, allergies, and damp-related problems. Hydronic underfloor heating (UFH), which pairs perfectly with renewable heat sources, such as air source heat pumps, provides the ideal solution. Unlike traditional radiators, UFH uses radiant heat that does not rely on moving air currents to warm the room. This reduces the movement and spread of airborne particles, creating a cleaner indoor environment.

Another key benefit of UFH is its natural ability to regulate humidity levels, creating a healthier home. The consistent, even warmth it provides helps prevent cold spots and areas where mould can develop, leading to maintenance issues and potential respiratory problems.

Mould growth can be a significant concern, particularly in well-insulated, airtight homes. While ventilation is essential, simply opening windows and doors isn’t always practical when conserving energy, which is a priority during colder months. Even with ventilation, condensation can still form if warm, moist air comes into contact with a cold surface below the dew point.

UFH offers a practical solution by generating heat across the entire floor surface, warming the room from the ground up. This radiant heat ensures an even temperature throughout, reducing the risk of cold surfaces where moisture can settle. By minimising damp conditions, UFH helps improve IAQ and reduces the likelihood of mould growth, creating a healthier, more comfortable living space.

When working alongside a specialist UFH partner to support design and installation, self-builders can feel confident that integrating UFH into the project will enhance comfort and efficiency while also supporting long-term health and well-being.

OPTIMAL PERFORMANCE & CONSISTENT WARMTH

Stable and constant spatial air temperature is essential for creating a comfortable and energy-efficient environment. When selecting a heating system, it’s vital to understand its performance at the heat source and across the room. This knowledge ensures comfort, efficiency, and practical room layout.

Research from Energy House 2.0 revealed that UFH has the smallest temperature variation, showing only a 0.8°C difference during tests at -5°C and 0.7°C at +5°C when operated in a SAP heating pattern. This performance is significantly better than that of other heating technologies, which demonstrated variations of up to 4°C, and traditional radiators, which had a minimum spatial difference of 2.2°C. The results also demonstrated even less spatial difference was seen when the system was run in a constant ‘on’ scenario.

The research proves that, when combined with air source heat pumps, the constant heating pattern achieved by hydronic UFH maximises efficiency and comfort, ensuring optimal performance and consistent warmth throughout the living space.

However, when evaluating heating technologies, it’s essential to consider more than just air temperature in isolation. Factors such as heat loss during off periods, the time required to reach the desired temperature, and the balance between running costs and occupant comfort all play a crucial role.

A system that is cheaper to run but slow to heat offers little benefit if comfort levels are only reached late in the day. A detailed review of the report reveals that UFH delivers the most consistent and comfortable warmth. When holistically accounting for cost and performance, any price difference between UFH and the most cost-efficient alternative is minimal and arguably negligible.

Self-builders can also feel assured by the results from the Final Summative Assessment of the Energy House 2.0, which concluded that underfloor heating systems’ running costs are lower than traditional radiator-only systems. ​This is due to their efficient design, which maximises heat output while minimising energy input.

A COOL COMBINATION

With summers becoming hotter, homes are at increasing risk of overheating. Part O of the Building Regulations, which took effect in England in June 2022, defines requirements for mitigating overheating in new residential buildings.

An emerging solution is the UFH system combined with a heat pump and run in reverse to offer a passive or near-passive means of heat removal. The system requires no additional or special components besides a control system designed for cooling and heating.

Radiant cooling provides a fresh perspective on indoor climate control and aims to work entirely in harmony with nature rather than against it. Instead of forcing cold air out, radiant cooling works by using cold surfaces to remove the heat radiated from objects within a room. 

Ashley Cooper is managing director at WMS