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.
A standard garage door has an R-value of zero (R0.0). That means it provides no resistance to heat and cold transfer – it’s like leaving a very large window wide open to the elements all year round. Considering that a garage door can take up to a third of your home’s front façade, leaving it uninsulated can undo the benefits of insulating everywhere else.
Most Australian homeowners think about insulating walls, ceilings, and windows. But one of the largest and most overlooked thermal weak points in the home is the garage door.
An R-value measures how well a material resists heat transfer, but unlike walls or ceilings that provide some resistance, a standard garage door starts at R0.0, offering no insulation until it’s upgraded.
That’s why quoting wall or ceiling R-values for garage door products is misleading and often overstated.
Here’s how common building elements compare:
Solid brick or block wall (no cavity): R0.3–0.4
Even without insulation, brick and block walls provide some natural thermal resistance.
Uninsulated cavity brick wall (double brick with air gap): R0.5
The air gap adds thermal performance before any insulation is installed.
Insulated cavity brick wall (with cavity fill): up to R1.3
Here the insulation is supported by the existing wall structure, boosting the overall R-value.
Standard garage door: R0.0
Unlike walls, a garage door has no inherent thermal resistance. It starts from zero.
This is why using R-values from wall or ceiling insulation to market garage door products exaggerates performance. Walls already contribute to the R-value, but a garage door doesn’t. Unless the insulation is purpose-built and tested as part of a garage door assembly, the numbers are inflated and don’t reflect real performance.
By contrast, ThermaDoor Premium is Australia’s only garage door insulation with independently verified door-assembly R-values: R1.48 (winter) and R1.43 (summer), tested specifically for sectional and tilt doors. This ensures homeowners get accurate, real-world performance – not overstated numbers borrowed from walls or ceilings.
Garage doors are made of steel or aluminium skins and frames, so thermal bridging lets heat flow straight through. That’s why, as a complete assembly, they’re considered R0.0 without proper insulation.
Thermal bridging occurs when a highly conductive material (such as steel or aluminium) allows temperatures to bypass insulation. In garage doors, the entire frame and panel skins are made from metal, meaning:
Temperature fluctuations flow easily through the framing and door skin.
Any insulation glued directly to the panel surface loses effectiveness.
The door assembly is considered R0.0 (unless the insulation system is tested as part of the complete door).
This is why accuracy matters. Some companies promote ‘standalone’ or material R-values of the products they sell as garage door insulation, but those numbers don’t reflect the impact of thermal bridging in garage doors once that product has been installed.
ThermaDoor Premium is Australia’s only purpose-built garage door solution, designed to overcome thermal bridging and deliver tested, real-world results.
Tested dual-season assembly R-values: R 1.48 (winter) / R 1.43 (summer)
Accurate results because testing accounts for thermal bridging in the full garage door system – not just the insulation board.
Supports NCC 2022 7-Star NatHERS ratings for new builds
Installed by professionals to ensure spring balance, safe fixing (no gluing), and warranty protection
With ThermaDoor, your garage door goes from R0.0 liability to a proven, high-performing part of your home’s energy-efficient design.
Insulated garage doors make a measurable difference to home comfort, lowering energy costs and boosting the thermal performance of adjoining rooms.
By insulating your garage door with ThermaDoor Premium, you:
Reduce heating and cooling costs
Improve thermal comfort in the garage and adjoining rooms
Gain accurate, tested R-values that reflect real-world performance
Avoid inflated performance claims
Ensure compliance with Australian Standards and NatHERS modelling requirements
Add value and long-term durability to your home
Leaving your garage door at R0.0 leaves a major gap in your home’s insulation, but a tested system like ThermaDoor Premium closes the gap with proven results.
ThermaDoor Premium Garage Door Insulation is purpose-made and tested to deliver accurate results, giving you compliance, comfort, and confidence.
Want to know more about performance claims regarding garage door insulation in Australia? Read our blog: Insulated Garage Doors: Why R-Values Matter More Than “Temperature Drop” Claims
A standard garage door has an R-value of 0.0. This means it provides no thermal resistance at all, allowing heat to freely pass through. Compared to walls (R0.3–0.5 uninsulated, R1.3 insulated), garage doors are the weakest part of the home’s thermal envelope.
Garage doors are made with metal frames and skins, which are highly conductive. This creates thermal bridging, where heat bypasses insulation completely. Without a purpose-made insulation system, a garage door offers no barrier to heat transfer.
Thermal bridging happens when metal components in a structure carry heat directly through, bypassing insulation. Garage doors are especially vulnerable because they are almost entirely metal-framed. This is why raw material R-values don’t apply — the door system must be tested as a whole.
No. The garage door’s metal frame actually reduces insulation performance. ⚠️ Beware of claims that the door increases R-value. Only tested, garage-door-specific insulation systems provide accurate results.
The best way to improve your garage door’s performance is to install ThermaDoor Premium Garage Door Insulation. It delivers tested dual-season R-values (R1.48 winter / R1.43 summer) that account for thermal bridging and comply with AS/NZS 4859.1 & .2:2018 and AS 3999.
Because of thermal bridging, quoting raw material R-values is not an accurate reflection of true performance. Tested systems like ThermaDoor Premium account for the full garage door assembly, giving you accurate results.
Yes. An insulated garage door reduces heating and cooling costs, improves comfort in adjoining rooms, supports compliance with Australia’s energy standards, and adds value to your home.
Request a copy of our thermal engineering report or get a free quote
Australian Government – Your Home: Insulation Guide
Explains how R-values are calculated and why insulation performance depends on the entire system, not just raw material values.
Home Base Perth – Passive Design: Insulation Installation Guide (PDF)
Provides typical R-values for solid walls, cavity walls, and insulated wall systems in Australian homes.
ABCB – Energy Efficiency in NCC 2022 & Beyond
The regulatory & performance framework for energy efficiency in residential buildings under NCC 2022; includes materials on thermal bridging mitigation, affordability, and whole-house energy performance.
CSIRO – Supporting Increased Residential Energy Efficiency: NatHERS & Performance Requirements
A factsheet summarising how energy efficiency standards have evolved in Australia, including the transition to NCC 2022 and what that means for thermal performance.
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