Do radiator reflectors actually work?
A small but real effect on uninsulated external walls, and close to nothing anywhere else.
- Difficulty
- beginner
- Time
- 30 min
- Read
- 2 min
Short answer
They help on a radiator fixed to an uninsulated solid external wall, and barely at all on an internal or well-insulated wall. Cheap enough to be worth it in the first case, pointless in the second.
A radiator on an external wall loses some heat backwards into the wall. Reflective panels return part of that into the room. The size of the effect depends entirely on how well insulated the wall behind is, which is why claims about them vary so much.
Step by step
- Check what is behind the radiator.An uninsulated solid external wall is where these help. An internal wall, or a well-insulated one, means there is very little loss to reflect back.
- Buy purpose-made panels or use foil-faced board.Purpose-made reflective panels, or foil-faced insulation board cut to size. Plain kitchen foil works poorly — it needs a low-emissivity surface and an air gap.
- Measure the radiator and cut to fit.It should cover the wall behind the radiator without being visible from the sides. Slightly smaller than the radiator is right.
- Clean the wall first.Adhesive panels need a clean, dry, sound surface. Dusty or flaking paint means they fall off within weeks.
- Fit it behind the radiator.Some slot behind without removing it; others need the radiator taken off the brackets, which usually means draining it. Check before buying.
- Leave an air gap.The panel should not press tight against the radiator. The gap is part of how it works.
- Be realistic about the saving.A small percentage of that radiator's output on an uninsulated wall. Real, but not transformative — do not expect it to replace insulation.
- Prioritise the bigger measures.Loft insulation, draught-proofing and radiator balancing all save considerably more for comparable effort.
Tips
- They are most worthwhile in older houses with solid uninsulated walls — the same houses where the wall behind is genuinely cold.
- Do not cover the radiator itself or restrict the airflow around it. Everything depends on air moving up its face.
- Balancing the radiators and fitting thermostatic valves saves considerably more and costs little.
Questions people ask
Do radiator reflectors save money?
A small amount on radiators fixed to uninsulated external walls. Very little on internal or insulated walls. Cheap enough to be worth it in the first case.
Can I just use kitchen foil?
It works poorly. The effect depends on a low-emissivity surface and an air gap, which purpose-made panels or foil-faced board provide and loose foil does not.