Does foil behind radiators help keep your house warmer? Experts reveal all

Experts reveal that not only does foil behind radiators work, but it actually offers serious energy-saving results.

There are plenty of clever tricks to restrict draughts and make your house feel warm for less, but very little to boost the performance of our heating solutions. Obviously, it's still important to act on autumn maintenance jobs of bleeding and cleaning radiators and following the 30cm furniture rule. But if none of those have helped boost your indoor temperature, it's time to grab some foil.

An on-trend budget solution, many are turning to foil behind the radiator this winter, as a cost-effective way to avoid boosting the thermostat. We look at how and why it works below.

Does foil behind radiators work?

Foil behind the radiator is the on-trend budget solution many are turning to this winter, and for good reason, because it actually works. Using radiator reflectors can indeed be an easy way to ensure you are heating your home more efficiently. "Radiator foil absolutely works to keep homes warmer when installed correctly," explains Chad Bragg, an insulation expert at SuperFOIL.

"Radiators lose a significant amount of heat through the wall behind them, especially on external walls. Reflective insulation redirects up to 95% of radiant heat back into the room, rather than letting it escape outdoors, thereby improving efficiency and comfort almost immediately."

"These reflectors keep warmth from being lost straight through your walls, reflecting it towards your living space, where it can have the most impact. Homeowners report that this small change can help to keep your house warmer and even allow you to lower the thermostat by as much as three degrees.”

Chad Bragg

Serving as SuperFOIL's Head of Technical and Compliance, Chad Bragg has over a decade of experience in the construction industry and is a specialist in technical insulation specification and thermal U-value calculations. Chad is also a dedicated educator, having delivered thousands of hours of CPD training to professionals across the built environment, from architects to building control officers.

Such a simple solution for improving insulation is an easy way to save energy around the home. "It won’t replace proper wall insulation, but it’s a fast, low-cost way to improve thermal performance and reduce heating bills, especially during colder months," says Chad. "Radiator foil is most effective behind radiators on external or uninsulated walls, particularly in older homes."

Top tip: "Installation is simple, but precision matters," says Chad. "Cut the foil to fit the radiator area, fix it securely to the wall behind the radiator (not on the radiator), and leave a small air gap if possible. This is what allows the foil to reflect heat rather than conduct it. No specialist tools are required, and most people can install it in under 10 minutes."

Which type of foil works behind radiators?

While experts agree that placing foil behind radiators is effective, it only applies if you use purpose-made insulated radiator foil, not standard kitchen foil.

"Many people assume kitchen foil will do the job, but standard aluminium foil is thin, fragile, and tears easily – and it doesn’t maintain an effective air gap, which is essential for reflection to work properly," Chad explains. "It also doesn't contain the same reflective properties as purpose-made radiator foil."

"The specialist radiator foil is designed to be highly reflective and insulated, meaning that it reflects heat into the room instead of allowing it to escape through external walls," explains Nicholas Auckland, a heating specialist at Trade Radiators.

"Standard kitchen tin foil, on the other hand, offers little to no insulation at all. This means that any energy or money-saving properties of the foil being used are minimal to none."

Nicholas Auckland

Nicholas is a heating and energy expert with over 10 years of experience in the industry. Nicholas is dedicated to finding the best heating solutions for every need, as well as optimising energy usage, reducing costs and helping others live with lower-cost energy bills.

Are there any disadvantages of foil behind radiators?

While there aren't direct disadvantages in terms of energy efficiency, Nicholas does highlight a few things you should be aware of when using radiator foil to improve your heating...

• They offer a more limited impact on internal walls: "If your radiator is on an internal wall, then the heat isn’t being lost outside the property, so the benefit is much smaller. While it will still work to keep the heat inside the room instead of it escaping, you won't feel the major impact that you would if they were on external walls."
• Proper installation is key for them to be most effective: "The foil needs to be fitted neatly behind the radiator, with the reflective side facing the radiator. Poorly fitted foil can slip or crease, meaning it's much less effective. Always follow the manufacturer's instructions for the specific foil that you've bought."
• They are not a standalone fix: "While foil does help the heat loss, it won't help with any other issues or heat loss problems that are caused by poor insulation. Draughty windows, uninsulated lofts, poorly insulated walls are all things that negatively impact how the heat from your radiators stays inside the house".

Experts already warn about the inefficiency of leaving the heating on all day, so the last thing you want is for the heating you do run to be wasted. This simple solution can go a long way to help your heating work more efficiently, without driving bills up.