Foil behind radiators saves you money and keeps you warmer - a practical guide

How much money did I waste?

I've read for a long time that a great deal of energy can be saved by applying foil to the walls behind radiators. This reflects the heat back into the room, rather than it dissipating into the walls. This is especially true of radiators located on an outside wall and even more true if these walls are either thick old stone, or walls with a cavity but without insulation. However, for one reason or another, I'd never done much about it, until recently.

Having now done it, I can say with certainty that it's made an amazing difference to our rooms and living conditions. The living room, for example, feels cozy so quickly, which is not something we're used to!

Apparently placing foil behind radiators can make an energy saving of 20% to 40%, but I don't know how this can be truly quantified as every house and situation is different - which is perhaps why I also stayed away from doing anything about it. All I can say, again, is that it's made a huge difference to our sense of comfort in the house and presumably to our oil burn rate as well.

What follows is an easy guide on how to fix foil behind radiators, as well as a look at the types of foil available, and lastly, some links to useful energy saving resources (both US and UK).

A recent hub of mine also explains how to insulate a loft - 25% of heat escapes through an uninsulated loft, so you can imagine how much money that translates to.

An example of a radiator panel being inserted, possibly using sticky tape
An example of a radiator panel being inserted, possibly using sticky tape | Source

Foil Types - panels or reflective foil

There are two basic types on the market, panels or foil. Usually, you don't need to remove your radiators to fix any of these. Of the panel type there are 3 basic designs that can be purchased.


1 - Flexible panels covered with upward facing ridges, the theory being that it stops the cold air falling and so contributes to the overall effect of convecting heat upward.

2 - Flexible panels without ridges

3- Solid flat panels

Various fixing methods are possible.

  • Some come supplied with magnetic strips (usually the panels that are ridged) and spacers so that they just slide onto the back of the radiator - no glue or sticky tape needed! An easy option, but the most expensive which might be a consideration if you have plenty of radiators.
  • A pole supplied which stretches across the two brackets and from which the panel hangs - again, this is most likely to be supplied with the ridged variety.
  • Double sided sticky tape.
  • Glue. Non corrosive glue is necessary so that the polystyrene backs don't melt. Using PVA is ideal - see below.

Reflective Foil

Most people will be familiar with the idea of foil rather than panels and this is what I opted for (cheaper).

I used a bonding material (PVA) which I had in the house rather than sticky tape, as I felt that glue would give some leeway for re-adjusting the position of the foil, whereas sticky tape would not. Also, having bought the cheaper more flimsy kind of foil, it wasn't suitable to put on with sticky tape.

It was an easy task to do and the next part of this hub explains the procedure.

First of all, you will need the following:

  • Measuring tape
  • Scissors or Stanley knife
  • Ruler and pencil
  • PVA adhesive + old jar to prepare it in
  • Paint brush
  • Long handled roller and sleeve
  • A space to prepare the pieces!

Measure and cut

That might seem a bit obvious, but you need to measure - and you don't need the foil to be showing higher than the radiator. There will be extra efficiency for having the foil wider and higher than the radiator itself but I've found that having it neatly behind the radiator already creates a massive improvement. If you need one and a half widths of roll between the spacers, try making a straight line with a pencil and ruler before cutting a length in half - it's much better for there to be no gaps between the strips! If there's a lot of space still uncovered at each end (the outer sides of the brackets), it's probably worth putting a narrow strip down there too.

Keeping the foil level with the radiator might be the best option
Keeping the foil level with the radiator might be the best option

Slap the glue on

It's up to you whether you want to roll some PVA directly onto the wall or not. I opted for applying it to the back of the foil (which is polystyrene), as I didn't want any PVA to be potentially running down the wall and onto the skirting board and carpet. In terms of water to glue ratio, I used 3:1 which might be excessive, but I take no chances! Load your paint brush and slap it on.

This roller handle needs a sleeve!
This roller handle needs a sleeve!

Apply the foil

This is the trickiest bit to get right, as there isn't much space to maneuver. I found that sliding the sheet down into an approximate position was ok, and making sure that the bottom end was horizontal to the radiator first of all. There was enough give to rotate the top a little, and unruckle a few bumps by teasing it around a little. Once I was happy with the result I used a long handled roller with a clean and dry roller sleeve to press the whole thing down with. There were still a few humps here and there, but I don't think that really matters. Getting the two pieces to join on the vertical is more important really.

This doesn't look too bad - and the amount of heat the radiator now kicks out is amazing.
This doesn't look too bad - and the amount of heat the radiator now kicks out is amazing.

The Result

If everything has gone to plan, the foil/panel will only show a little, and when the heating next comes on, you'll be happy to feel the warmth rising through the room faster than before.


Useful energy saving resources

A great resource on all aspects of energy saving

The Energy Saving Trust - UK

Energy - US - this is PDF file and takes a while to load

As a kind of general overview, I found this diagram excellent as it brought home to me all of the factors in one glance:

kinds of radiator panels:

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Comments 4 comments

rfmoran profile image

rfmoran 4 years ago from Long Island, New York

Voted up and useful. I have a big old (166 years) house with steam radiators all over the place. Thanks for your heat and money saving ideas.

Electro-Denizen profile image

Electro-Denizen 4 years ago from Wales, UK Author

Thanks rfmoran - we too live in an old house, constructed late 1800's. Couldn't believe the improvement foil made in our case. Perhaps new builds don't benefit from foil quite as much.

Emma Harvey profile image

Emma Harvey 3 years ago from Berkshire, UK

Great hub - I'm all for insulating the home and saving energy. Our house is also quite old and so cold in the winter. I will get some reflective foil for our radiators - such a simple yet effective technique - thanks.

Electro-Denizen profile image

Electro-Denizen 3 years ago from Wales, UK Author

Thanks for dropping by EmmaHarvey. I think you'll feel the improvement.

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