FENSA-registered glazing experts. Made-to-measure sealed units, shipped UK-wide, backed by a 10-year warranty.
36mm triple glazing — the Scandinavian-default stock thickness
36mm is the most common triple-glazed sealed-unit thickness across the Nordics — a 4mm + 14mm + 4mm + 14mm + 4mm stack with argon or krypton fill and one or two low-E coatings. It's the stock thickness that fits the rebate on standard Internorm, Velfac, NorDan, Rationel, and Smart Architectural Aluminium frames, and it's the thickness most UK self-builders end up specifying when they swap out builder-spec UPVC for serious thermal-performance frames. Pane Relief manufactures 36mm triples to UK build to suit a range of UK and continental frames — argon-filled for budget builds (U=0.9-1.0 W/m²K) and krypton-filled with dual low-E for PHI-grade performance (U=0.6-0.7 W/m²K). Use this collection when the rebate spec is locked at 36mm and you need to specify what fills it.
Frame is already specced 36mm — pick the glass
You've chosen the windows (Internorm, Velfac, NorDan, etc.) and the frame manufacturer has confirmed 36mm rebate. This collection is where you specify the glass that goes inside — argon vs krypton, single vs dual low-E, toughened safety, laminated acoustic. Free spec validation on the helpline, 10-year edge-seal warranty, FENSA installer recommendations for replacement projects.
Configure my 36mm tripleInstaller, builder, retrofit specialist
Net 30 trade accounts, tiered discount on 5+/20+/50+ unit orders. 36mm triple is the default stock spec for Scandinavian and German-style frames — we hold stock-size argon builds for fast turnaround on developer schemes. BS EN 1279-5 DoP, krypton-fill certificate (where applicable), and coating data sheet shipped with every order on request.
Trade pricing & bulk ordersWhich 36mm triple build do you need?
Five common 36mm builds, each tuned to a different price/performance point. All fit the same rebate.
Standard 36mm argon
4-14-4-14-4 argon-filled with single low-E coating. U=1.0 W/m²K. Builder-spec triple at lowest price point.
36mm argon dual low-E
Low-E on faces 2 AND 5, argon fill. U=0.85 W/m²K. Best argon spec at 36mm — just below PHI threshold.
36mm krypton PHI-spec
Dual low-E + krypton fill (≥95%). U=0.6-0.7 W/m²K. Passivhaus-component-grade in a 36mm frame.
36mm + toughened safety
36mm triple with one or both panes toughened to BS EN 12150. For doors and low-level critical-location glazing.
36mm + acoustic laminated
6.8mm Optiphon/Stadip Silence laminated outer pane. U=0.7-0.9 W/m²K, Rw 40-44 dB. Urban Passivhaus.
Other PHI triples
If your rebate is 44mm or larger, the full PHI tri-glazing collection has more options and lower U-values.
Why 36mm is the Scandinavian default — and what it means for spec
A short explainer on the geometry that drives this stock thickness, and how to confirm 36mm is the right call for your project.
The 5-point 36mm primer
- Stack geometry: 4mm + 14mm cavity + 4mm + 14mm cavity + 4mm = 36mm overall. The 14mm cavities are at the gas-conductivity sweet spot for both argon (best at 14-16mm) and krypton (best at 8-14mm).
- Frame compatibility: Internorm KF410, KF500; Velfac 200; NorDan TT-Termo; Rationel AURAPLUS; Smart Architectural Aluminium Visoglide. All speced for 36mm triple as standard.
- Performance ladder: with argon + single low-E you land at U=1.0; with argon + dual low-E at U=0.85; with krypton + dual low-E at U=0.6-0.7 (PHI-component territory).
- Weight: approximately 30 kg/m² — within tolerance for all rated Passivhaus frames. Check legacy timber frames before retrofit.
- Confirm before ordering: measure the actual frame rebate. Some frames quoted as "36mm-compatible" actually have a 35.5mm or 37mm clear rebate — within tolerance, but worth confirming.
Pricing & documentation
Prices on this collection are "From £X" at the smallest stock size on the argon + single low-E build. Krypton fill, dual low-E, toughened safety, and acoustic laminated upgrades priced live in the configurator. Coating data sheet and (where applicable) krypton-fill certificate shipped on request — no charge.
36mm triple glazing — common questions answered
Q: Why 36mm specifically? Why not 32mm or 44mm?
It's a frame-rebate convention. 36mm is the most common triple-glazing thickness on Scandinavian and German-spec frames — the depth that gets the best balance of cavity-width optimisation, glass weight, frame depth, and sash mechanism design. 32mm exists but compromises argon performance (cavities are too narrow). 44mm gets fractionally better U-values but requires deeper frame profiles and adds weight. For most Passivhaus-class UK frames, 36mm is the spec ceiling without going to a thicker frame profile.
Q: Argon or krypton on 36mm — does it matter?
Yes — but not as dramatically as on slim DG. At 14mm cavity width, argon and krypton are both in their effective range. Switching argon to krypton drops U-value by about 0.15-0.25 W/m²K on a 36mm dual-low-E build (e.g. from U=0.85 to U=0.65). For PHI certification you'll need krypton; for general thermal upgrade where U=0.85 is fine, argon is the budget choice.
Q: My frame is rated 36mm but the rebate measures 35mm — is that a problem?
No — manufacturing tolerance. A 36mm sealed unit is typically built to +/- 0.5mm so the actual unit dimension might land anywhere in 35.5-36.5mm. Glazing gaskets and tape accommodate the variance. If the measured rebate is 34mm or below, that's a different conversation — order the 32mm slim-triple build instead, or confirm whether the frame can be re-machined.
Q: What's the weight of a 36mm unit?
Approximately 30 kg/m² at 4mm pane thickness throughout. A 1.2m x 1.5m casement unit weighs about 54 kg — within the rating of every Passivhaus-spec frame on the market, but at the upper limit for legacy timber casement frames. Hinge rating: typically requires 3-hinge or 4-hinge configuration on units over 1.5m².
Q: Can 36mm hit PHI U-values?
Yes — with the right stack. A 36mm krypton dual-low-E build with Swisspacer Ultimate warm-edge spacer typically lands at U=0.65-0.70 W/m²K. That's PHI component-grade. The "ultra" U=0.6 or below builds tend to use 44mm or 48mm depths to get the most out of the krypton cavity-width optimum, but 36mm with the right stack gets you to PHI threshold.
Q: Will 36mm fit my UK UPVC casement frame?
Usually not — standard UK UPVC casement profiles are rebate-designed for 24mm or 28mm DG, not 36mm triple. Forcing a 36mm unit into a 28mm rebate is impossible. Solutions: (a) replace the frame with a Passivhaus-rated profile, (b) use a 28mm dual-low-E krypton DG from the Passivhaus double-glazing collection, or (c) commission a custom-rebate frame from a specialist manufacturer. The Pane Relief Passivhaus desk can route the conversation.
Q: How does 36mm compare to 44mm for performance?
44mm with the same stack typically lands at U=0.55-0.65 (vs 36mm at U=0.6-0.7). The 8mm extra cavity depth optimises the krypton fill slightly better. But 44mm is heavier (33 kg/m² vs 30) and only fits deeper frame profiles. For most Passivhaus retrofits and new-builds with 36mm-rated frames, the difference isn't worth specifying around — 36mm clears PHI and performs perfectly well. 44mm is for new-build specifying for the lowest possible U.
Q: Lead time on 36mm triple?
Stock-size argon + single low-E 36mm triple: 7-10 working days. Argon + dual low-E: 10-14 working days. Krypton + dual low-E PHI-grade: 14-21 working days. Toughened or laminated safety upgrades: add 3-5 working days. Acoustic laminated 36mm: 14-21 working days. Emergency boarding for broken triple-glazed units: call the helpline.
Related guides and specifications
Need help speccing a 36mm triple build?
Call the helpline on 0117 330 3057 (08:00-18:00 Mon-Fri), or request a quote. Trade accounts unlock live tier pricing and Net 30 terms.