How to Choose the Best Reflective Film for Underfloor Heating

Not all reflective films are created equal. The quality of the aluminum layer, the durability of the backing, and the reflectivity rating can all affect how well the film performs in a real underfloor heating system. This guide explains what to look for when selecting reflective film.

Reflectivity Rating Matters

The most important specification is the film's reflectivity. High-quality films reflect up to 97 percent of radiant heat, while cheaper alternatives may reflect significantly less. A lower reflectivity means more heat escapes downward, reducing efficiency and increasing running costs. Always ask the manufacturer for the reflectivity rating rather than relying on marketing claims.

Backing and Durability

The backing layer protects the aluminum foil from tears, punctures, and moisture. A durable backing ensures the film remains intact during installation and over the life of the system. Look for films with a reinforced polyethylene or scrim backing that resists tearing. A vapor barrier layer is also valuable, especially on ground floors or over unheated spaces.

Key Specifications to Compare

• Reflectivity: Aim for 95 percent or higher.

• Thickness: Thicker films generally offer better durability.

• Width: Wider rolls mean fewer joints and less sealing required.

• Vapor barrier: Built-in moisture protection is valuable in damp environments.

• Tear resistance: Reinforced backing withstands foot traffic during installation.

Installation Tips

Lay the film with the reflective side facing up, overlapping joints by at least 10 cm. Seal all joints with aluminum foil tape to create a continuous barrier. Pay special attention to edges and corners, where gaps can reduce effectiveness. Avoid walking on the film with sharp tools or heavy equipment that could puncture it.

Conclusion

Investing in high-quality reflective film pays off in improved efficiency and lower running costs. By comparing reflectivity, durability, and vapor barrier performance, you can choose a film that delivers long-term value.

References

[1] Underfloor Heating Systems: Design, Installation and Performance. Journal of Building Engineering, Elsevier.
[2] Thermal Analysis of Radiant Floor Heating Systems. Energy and Buildings, Elsevier.
[3] Materials and Components for Underfloor Heating. Construction and Building Materials, Elsevier.