What is a material R-value and why does it differ from a system R-value?

A material R-value measures the thermal resistance of an insulation product in isolation. It does not account for the real-world assembly it is installed in. For a garage door — a metal structure subject to thermal bridging, air movement, and seasonal temperature variation — the material R-value will almost always overstate actual performance. This is why AS/NZS 4859.2:2018 requires total system R-values to be calculated for the specific assembly. ThermaDoor's declared values of R1.43 (winter) and R1.39 (summer) are system R-values, not material values.

Garage Door Insulation | Technical Resources & Industry Information

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Est. 2012

Australia's Original

Independently Tested

AS/NZS 4859.2:2018

Australian Made

Licence 7177

Purpose Built

For Garage Door Systems

What Makes ThermaDoor Different

Most products sold as garage door insulation are generic building materials — wall batts, PIR panels, foil wraps, or plain polystyrene sheets adapted for a use they were never designed for.

ThermaDoor is different — invented by a builder, it integrates with professional installation practices from the ground up, not as an afterthought.

Every panel is engineered specifically for the daily movement and thermal demands of a garage door system, and independently tested to Australian Standards. Here’s what’s inside every kit.

Three Layers. Engineered as One

High-Density EPS Core

Flame retardant, construction-grade expanded polystyrene foam is the primary insulator in every ThermaDoor panel. It slows conducted heat transfer through the door — keeping your garage significantly cooler in summer and warmer in winter, year after year.

UV-Stable Vinyl Facing

Durable, flame retardant, UV-resistant vinyl facing protects the panel from Australia's harsh climate. It resists fading, cracking, and weathering — delivering a clean, professional finish that holds its appearance and structural integrity for the life of the door.

Sisalation Foil Backing

Bonded to the back of every panel, this construction-grade foil reflects radiant heat, acts as a Class 2 vapour barrier, and achieves Group 1 fire performance classification. It's the same foil used to wrap Australian homes — completing the three-layer system.

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Partner With Australia's Leading Garage Door Insulation

Interested in Becoming a ThermaDoor Distributor?

We work with garage door businesses across Australia who want to offer a premium, independently tested solution that delivers results, generates referrals, and does not come back as a callback. Our panels integrate seamlessly with standard sectional and tilt door installations. Mechanical fixing only. No adhesives. No special tools. No waiting.

Customers ask for ThermaDoor by name — pre-sold demand before you quote
Reliable supply and delivery — give customers a firm timeline, not a maybe
No callbacks — factory-laminated panels do not delaminate or sag
NCC aligned — relevant for new build and renovation quoting

What Our Distributors Say

Chloe from Show It Off Home Improvements (Hervey Bay & Fraser Coast) shares her experience as a ThermaDoor distributor.

“One of the easiest companies we have ever worked with. Customers ask for ThermaDoor by name — and the reliable timelines mean we can give customers a firm date.”

— Chloe, Show It Off Home Improvements, Hervey Bay & Fraser Coast

See the Difference ThermaDoor Makes

Real installs. Real results. Read the full comparison.

Want to know more about foil products used as garage door insulation? Read our blog Failed Reflective Foil Insulation: Common Mistakes We See Across Australia.

	Before ThermaDoor	After ThermaDoor
Summer temperature	Garage reaches 50°C+	Noticeably cooler — less heat into adjoining rooms
Winter comfort	Cold, damp, unusable space	Warmer and more usable year-round
Noise	Traffic and rain echoes through	Significantly reduced outside noise
Energy bills	Heat transfers into home, AC works harder	Reduced heat load on your cooling system
Insulation fit	Generic products that don’t fit properly	Purpose-built panels cut to your exact door
Installation	Complicated DIY with wrong materials	Simple DIY kit or professional supply & install

ThermaDoor Warranty

ThermaDoor panels are backed by a manufacturer’s warranty covering defects in materials and workmanship. Our warranty reflects our confidence in the quality of Australian-made construction — because a product built to last should be guaranteed to last.

For Builders, Designers & Energy Assessors

ThermaDoor is Australia’s only purpose-built garage door insulation with independently tested, dual-season R-values — R1.43 (winter) / R1.39 (summer) — calculated to AS/NZS 4859.2:2018 and accepted as NatHERS inputs. Designed from the ground up for sectional and tilt garage doors, it is the only product that allows your energy assessor to include the garage door in thermal modelling with confidence.

Declared Assembly R-Values

Dual-season door assembly R-values — R1.43 (winter) / R1.39 (summer) — calculated to AS/NZS 4859.2:2018 and supported by independent engineering documentation

Flammability Classified & Vapour Managed

ThermaDoor Premium carries the correct flammability classification for insulation under AS 1530.2. The bonded sisalation foil backing achieves Group 1 fire performance classification and acts as a Class 2 vapour barrier — meeting NCC requirements for residential construction

Supports Your 7-Star Target

Because ThermaDoor provides assembly R-values backed by engineering documentation, energy assessors can include the garage door in NatHERS thermal modelling — helping achieve 7-star outcomes

Why the Garage Door R-Value Matters in NatHERS & the NCC

Under Australia’s National Construction Code (NCC):

This is the same framework your energy assessor applies in performance modelling. This means including a tested garage door R-value can make the difference between reaching and not reaching 7-star targets – especially when margins are tight.

That’s where ThermaDoor garage door insulation stands out.

ThermaDoor is the only Australian garage door insulation brand that publishes dual-season, door assembly R-values -R1.43 (winter) / R1.39 (summer) – now a requirement under the NCC.

“With over 30 years in the construction industry and as an energy compliance consultant, I have experienced firsthand how tested and verified ThermaDoor garage door insulation reduces heat transfer and improves thermal efficiency, enhancing natural thermal comfort. If your garage is air conditioned, or you plan to convert it into a liveable space, it also delivers measurable energy savings by improving heating and cooling efficiency.

If you are building a new home, it is a smart move to have your designer or architect specify ThermaDoor garage door insulation on the plan files. That way, your energy assessor can include it in the thermal modelling, so it is recognised in your NatHERS star rating outcome.”

— Helen Armstrong, Energy Compliance Consultant | 30+ years in the construction industry

Key Specs (At A Glance)

Specification	Detail
Application	Sectional and tilt garage doors — new builds and major renovations
Panel Thickness	35mm
Declared R-Value (Winter)	R1.43
Declared R-Value (Summer)	R1.39
R-Value Type	Dual-season door assembly (system) values — not material or wall values
Standards Framework	AS/NZS 4859.1:2018 (materials and test methods) and AS/NZS 4859.2:2018 (total/system R-value determination)
Fixing Method	Mechanical fixing — no adhesive or glue
Flammability	Flame-retardant EPS core — tested to AS 1530.2
NCC Compliance	Aligned with NCC building fabric provisions
NatHERS Support	Declared values suitable for NatHERS 7-Star design inputs

Thermal bridging makes garage doors a special case – see our detailed blog on Why Your Garage Door Has An R-Value of Zero – And How to Fix it

Garage Door Insulation FAQs for Builders & Energy Assessors

Can I use wall or ceiling R‑values for a garage door in NatHERS?

No. Wall and ceiling R-values are calculated for static building elements. A garage door is a moving assembly with different thermal properties — it requires a door assembly R-value calculated specifically to AS/NZS 4859.2:2018 to be used as a valid NatHERS input.

Where do the ThermaDoor R‑values come from?

ThermaDoor R-values are independently calculated by James M Fricker, F.AIRAH F.IEAust CPEng, Registered Professional Engineer (Victoria PE0005355), to AS/NZS 4859 Parts 1 & 2:2018. The declared values are R1.43 (winter) and R1.39 (summer) for the door assembly.

Does garage‑door insulation help achieve 7‑Stars?

Yes — when the garage door has a declared assembly R-value supported by engineering documentation, your energy assessor can include it in NatHERS thermal modelling. In homes where the garage is attached or the garage door faces a thermally significant direction, this can make a measurable difference to the star rating outcome, particularly when margins are tight.

Is this recognised in the NCC?

ThermaDoor R-values are calculated to AS/NZS 4859.2:2018, which is the methodology referenced by the NCC for total/system R-value determination. The product meets the framework the NCC requires for insulation to be assessed in performance modelling.

What about a material R-value (sometimes referred to as a 'standalone' R-value)?

A material R-value measures only the insulation layer in isolation. An assembly R-value — which is what ThermaDoor publishes — accounts for the full door system including air gaps, facing materials, and thermal bridging. The assembly R-value is what NatHERS assessors need and what the NCC methodology requires.