Peter is a licensed builder with over 45 years of experience in the construction industry. In 2012, his expertise in energy efficient construction inspired the invention of ThermaDoor Premium garage door insulation - the original purpose made garage door insulation in Australia.
If you are looking for garage door insulation in Australia and are tempted by these stick-on foil kits, this article is for you. Here is the simple science behind why they fail, and what a real solution looks like.
This is not a theoretical number from a wall. This is the verified, real-world thermal performance you get when you install ThermaDoor on your garage door. It is the difference between a product that looks like insulation and a system that actually is.
A: Not when it is glued directly to the door. For reflective insulation to work, it needs a still air gap facing the foil surface. In a sectional or tilt garage door, the available air gap between the door skin and any insulation is only around 6 to 9mm. That is a fraction of the 70mm or more that wall-tested R-values are based on. When foil is pressed flat against the metal, heat conducts straight through and the reflective properties become irrelevant. This is why so many homeowners report that stick-on foil kits made no difference at all.
A: The most important thing is not the number itself but whether it is backed by an independent engineering report. Many products on the market quote R-values with no test report, no engineering documentation, and no methodology to explain how the figure was calculated. These numbers appear to be little more than a guess, and there is no way to verify them. Always ask for the engineering report. ThermaDoor’s system R-values of R1.48 winter and R1.43 summer are independently verified and calculated specifically for a garage door assembly, not borrowed from a wall or ceiling test.
A: There are two common reasons. The first is that the R-value has been taken from a wall test, which assumes a large air gap that simply does not exist on a garage door. The second is that no independent test report exists at all, and the number has been stated without any engineering basis. Under Australian Standards, R-values must be declared for the specific application and assembly. A figure quoted without a supporting test report should be treated with serious scepticism.
A: Absolutely, when it is done properly. A well-insulated garage door makes the space more comfortable year-round, protects stored items from extreme temperatures, and reduces heat transfer between the garage and adjacent living areas. The key word is properly. A product that cannot demonstrate its R-value with an independent report is unlikely to deliver the comfort and energy savings you are paying for.
A: Cheap foil kits are a single layer of material glued to the door. As explained above, this approach does not work because the available air gap in a garage door is only 6 to 9mm and the foil is in direct contact with the metal. ThermaDoor is an engineered insulation panel with a fire-retardant, closed-cell foam core. It is mechanically fixed to the door, preserving the air gap and providing a genuine thermal break. Most importantly, its performance is backed by an independent engineering report, not a number pulled from a wall test or stated without any supporting evidence.
A: Yes. ThermaDoor is available as a DIY garage door insulation kit. The panels are pre-cut to fit your specific door and come with everything you need for a straightforward installation. We also have a network of professional installers across Australia if you prefer to have it done for you.
A: The cost depends on the size of your door and whether you choose professional installation or a DIY kit. Cheap foil kits may appear to be a saving, but if they provide no thermal benefit, the real cost is everything you spent for no result. A purpose-built system with a verified R-value is a genuine long-term investment. Contact ThermaDoor for a free, no-obligation quote tailored to your door.
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