What Is the Best Insulation for Underfloor Heating?

The best insulation for underfloor heating depends on the floor construction, heating system type, and required thermal performance. In the UK, PIR insulation boards and XPS insulation boards are among the most commonly used options because they provide excellent thermal efficiency and strong compressive strength.

Underfloor heating insulation boards help reduce downward heat loss, allowing more heat to move upwards into the room rather than being wasted into the subfloor. This improves heating performance, increases system efficiency, and can help reduce long-term energy costs in both residential and commercial properties.

Is XPS or PIR better for underfloor heating?

PIR insulation boards generally provide better thermal performance at lower thicknesses, making them a popular option where floor height is limited. They are widely used in modern underfloor heating floor build-ups because they provide high insulation values while keeping the floor profile relatively low.

XPS insulation boards offer excellent moisture resistance and compressive strength, making them suitable for wet rooms, basements, and areas exposed to higher moisture levels. Both insulation types are commonly used depending on the project requirements, flooring type, and structural loading conditions within the property.

What compressive strength should insulation boards have for UFH?

Most underfloor heating insulation boards in UK should provide enough compressive strength to support floor finishes, furniture, and regular foot traffic without deforming over time. The required compressive strength depends on the floor build-up and whether the system is installed beneath tiles, laminate, engineered wood, or screed. Higher compressive strength boards are often recommended for heavier floor loads and commercial applications.

Many underfloor heating insulation boards used in the UK are specifically designed to provide both thermal insulation and structural stability, helping maintain long-term floor performance and efficient heat distribution throughout the heating system.