Why Contractors Are Putting Aluminum Foil Behind Radiators, And Does It Actually Work

In the wake of rising heating bills and persistently frigid rooms have forced homeowners to investigate every method of efficiency. Some of the most intriguing methods being studied is the technique using aluminum foil to cover radiators. This may appear to be an easy kitchen trick however, this method is actually based in scientific research in the field of building. Construction companies and experts in energy efficiency have been implementing it more and more for older houses when they are in good circumstances, it could make a significant difference.

The Hidden Ways Radiators Lose Heat

For an understanding of why foil may aid, it's important to understand how radiators disperse the heat. The radiator is able to warm a space by convection, radiation and conduction. As convection circulates warm, the air, and radiation warms objects in direct contact, conduction permits warmth to flow into the walls surrounding the radiator.


If you live in a home with non-insulated or poorly-insulated walls, particularly those constructed out of stone or solid brick the loss of heat conductive is often significant. The study entitled Heat Transfer From Domestic Radiators to walls that was conducted by scientists in the field of building physics from the University of London and published in a leading international journal on energy, showed that a significant part of the heat production can be taken from the wall, rather than the space. The effects are more prominent when the temperature differential between outdoor and indoor temperatures is large, as occurs in warmer environments.

How Aluminum Foil Changes the Equation

Aluminum foil is an reflective shield with a minimal emissivity. It reflect infrared light to the outside rather than allowing walls to absorb the radiation. However it may disrupt the direct conductivity pathway that runs between the wall and the radiator.

The study by UK researchers of radiator heat transfer discovered that the use of reflective surfaces behind the radiator could reduce energy loss through walls substantially in controlled environments. Through redirecting the radiant heat to the inside the foil makes sure that much of the energy is used to heating the space instead of being absorbed by the structure.

What Research and Simulations Reveal

Beyond theories and simulations, studies on simulations provide an accurate picture of the potential savings. The study of thermal simulation, called the Performance Assessment of Reflective Panels for Radiators which was conducted by an European Building Energy Research Group and concluded that the addition of the reflective metal panel to an insulated radiator within a solid-wall residence reduced heat loss through the wall by as much as 54 percent. In the heat-peak times the reductions could be levels of up to 66 percent.

Even though simulations do not represent the ideal situation however, they show how significant the effects can be if the wall that surrounds the radiator is uninsulated and cold. The real-world data from energy efficiency companies reveal reflection-enhancing radiators could cut down on heat loss by 20 % to 30% in homes with older structures.

Why Contractors Recommend It for Older Homes

Many contractors advocate this approach since it's inexpensive and easy to set up, and doesn't require any significant changes. When it comes to older buildings, specifically the ones that have solid masonry walls, loss of heat through the walls is an ongoing issue. The retrofitting of full insulation is expensive and time-consuming, however the addition of a reflective layer between radiators can be a simple upgrade that will provide significant improvements in comfort.

The building science experts stress the efficacy of this approach is contingent on the kind of wall. For homes that have modern cavities, this value is smaller since walls are already able to resist the transfer of heat effectively. Professionals tend to apply foil in a specific way instead of putting it on top of each radiator.

Kitchen Foil Versus Purpose-Made Reflectors

The most frequent question is the question of whether kitchen foil from your local store suffices. Although it provides a amount of reflection, it's not as durable or effective like specially-designed radiator reflector panels. Studies in study on home energy from UK consumer housing associations reveals that special foils are more durable constructed, strengthened, and designed with low-emissivity surfaces. This allows them to reflect more of infrared light and keep the air gap around the radiator. This improves efficiency.

Kitchen foil, on opposite, can be prone to breakage and loss of its effectiveness when it is placed flush against the wall with no critical air space. Although it is a good option for an interim or cost-effective solution however, products that are specifically designed for use are the best long-term purchase.

What Experts in Building Science Say

Professionals have consistently described reflective foils as a radiation shield rather than simply an insulation material. When tested in controlled chambers that were conducted by scientists from the building sciences from the United Kingdom, reflective metal foils placed on radiators cut down heating transfer to the wall directly in front of the radiator. This resulted in improved performance of the room's thermal insulation.

Energy efficiency consultants have also pointed out that reflective surfaces could provide a substantial amount of the infrared energy into the living area. It not only makes your room to heat up quicker but also decreases the time that heating systems have to operate.

A Practical and Targeted Upgrade

The efficiency of aluminum foil lining radiators is ultimately determined by its context. If you live in older homes that have exterior walls that are cold and uninsulated they can dramatically enhance comfort and decrease consumption of energy. Rooms that used to be cold regardless of active heating are often the ones that gain the most.

For homes that are well-insulated The gains aren't that significant. For those homes, more extensive improvement like upgrading air sealing, insulating drafts or creating more efficient heating systems are more effective.

The Bottom Line

The aluminum foil used behind radiators isn't an unintentional gimmick. It's an easy implementation of physics which can lower heat loss and boost effectiveness under certain conditions. It's not an alternative to adequate insulation, it can serve as an effective inexpensive enhancement in older buildings, where the heat escapes via the exterior walls.

If you're a homeowner looking for sensible strategies to boost the budget for heating This small change could be an effective move towards a more comfortable and more energy efficient house.