Placing a simple sheet of foil behind radiators fixed onto external walls can reduce heat loss by more than 50%, according to engineers at boiler installation firm BOXT. The product, known as radiator foil or heat reflector foil, is a thin reflective sheet typically made from aluminium with an insulating backing.
With the energy price cap having increased by 3.6% at the beginning of this month, households across the UK are scrutinising their monthly outgoings more carefully. Despite government measures aimed at softening the blow of soaring wholesale oil and gas prices, energy bills have climbed to staggering levels, leaving many searching for ways to make their homes more cost-efficient.
How radiator foil works
For radiators fixed onto external walls, BOXT says it can benefit households to buy radiator foil to prevent heat loss to the outside world. The foil is positioned directly behind the radiator, ideally between the radiator and an uninsulated wall, allowing it to redirect warmth back into the room.
The principle is simple: rather than letting heat seep into walls, the foil acts like a thermal barrier, reflecting radiant heat back into the living space. BOXT maintains that these work because when a radiator is mounted on an external wall, particularly beneath a window, it exudes heat from the front and the back.
Savings and evidence
BOXT added that households could be losing around 50% of heat from the radiator to the external wall, which is not ideal. The Energy Saving Trust states that radiator foil can reduce heat loss through walls and help to save £18 a year on energy bills.
Research conducted by the University of Salford discovered that reflective foil could save approximately 2.9% of space heating gas consumption on a typical UK winter day, depending on insulation levels and radiator placement. The same research revealed heat loss through external walls could be cut by 54%, with optimal reductions of 66% during heating periods.
Radiator reflector foil can be purchased online for anywhere between £6 and £20 per roll.
Other radiator efficiency tips
Households can also improve radiator performance by keeping the area around them clear. Radiators operate on the principle that warm air rises through natural convection, with cold air drawn up through the bottom and released as warm air from the top. Any items placed on or beneath the radiator can disrupt this process.
Bleeding radiators can also help. If a radiator feels warm at the bottom but cool at the top, it likely needs bleeding, which involves releasing trapped air from the heating system. The process is straightforward and should take no longer than five minutes.
Cleaning radiators can also make a difference, as a build-up of dust can impede the flow of cold air and affect how much warm air is produced. Using a hairdryer can help dislodge dust from trickier spots.
