Disadvantages of Foil Behind Radiators & What To Avoid

Last updated: January 21, 2024

Does placing foil behind your radiators actually help slow down heat loss and save money on your heating bills?

As the name implies, radiators themselves are designed to radiate heat into their surroundings, e.g. into your living space.

The logic behind radiator reflectors is that they help the heat radiated from your radiator be reflected into your living space, as opposed to being lost in the wall behind the radiator.

But, what does the research data show? In this post we explore the facts and some potential strategies you can easily adopt to make the most out of your radiators.

Should You Put Foil Behind Your Radiators?

Specialised reflective foil, designed to redirect warmth back into your living space, is an effective strategy to conserve heat and provide insulation.

This method is particularly beneficial for external walls, where it helps to minimise heat loss. Enhancements like shelves or fans above radiators can further help to circulate warm air back into the room.

For a DIY approach, you can attach foil to cardboard panels and place them behind radiators, ensuring the reflective side faces the room.

Double-sided adhesive pads can also help to secure these panels in place.

But are there any disadvantages to installing foil behind radiators that you should be aware of?

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Disadvantages of Foil Behind Radiators

Why should you use tin foil or aluminium foil behind your radiators?

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The main reason you should not use traditional kitchen foil behind your radiators is simply that it isn’t designed for this purpose.

These are the major reasons why aluminium foil is a bad idea (as opposed to purpose built radiator reflectors):

  • Foil will crinkle and is unlikely to stay in the same position for long.
  • Over time, foil will degrade and oxidise, diminishing its ability to reflect heat.

Why use radiator reflectors instead?

The alternative to placing foil behind your radiators is a radiator reflector like those offered by the brand Radflek – easily found on Amazon.

Unlike tin foil, these will not be at the mercy of oxidisation and will maintain their shape and integrity over time.

Radiator Reflectors Real Term Savings

How much energy and money can you save by installing radiator reflectors?

Research was carried out by the BRE and shows that substantial savings can be made by installing Radflek radiator reflectors.

Type of PropertySavings per radiator / yr (0.6sqm)Payback (Years)
Insulated Cavity Walls£0.803.7
Post 1983 Cavity Walls£1.322.3
1976-82 Cavity Walls£1.911.6
Pre-1976 Cavity Walls£2.751.1
Uninsulated Solid Walls£4.020.7
Table updated: January 2024.

The British Board of Agrément (BBA) and verified by the BRE, also highlight that Radflek products can reduce heat transfer through walls by 45%.

In Summary

Placing foil behind radiators can reflect heat into living spaces, potentially saving on heating bills, especially effective on external walls.

However, kitchen foil isn’t ideal as it degrades and crinkles over time. Specialized radiator reflectors like Radflek are more durable and effective.

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Research indicates these can significantly reduce heat transfer and provide real-term savings, with the amount saved varying by property type and wall insulation.

The British Board of Agrément confirms that Radflek can reduce heat transfer by up to 45%.