Project-specific U-value and SHGC — not a DTS default.
BTW models the actual windows in your project to ISO 15099 / NFRC 100 — the real size, system and glass, not a catalogue rating. Often a better, less over-specified result than the Deemed-to-Satisfy default, and the evidence a Performance Solution needs.
Model the window you’re actually installing
The Deemed-to-Satisfy path leans on generic, standard-size ratings. BTW is the other compliance path — your project’s real window, modelled directly, with the full set of outputs on one model.
The real assembly
Real size, system, glass and sub-frames — modelled to ISO 15099 / NFRC 100, the same method behind the ratings, run on your actual window.
Often a better number
Projects use larger windows than the standard test size, and Uw is area-weighted — so the modelled result is frequently better and less over-specified.
More than a rating
One model returns Uw, SHGC and Tvis — and feeds condensation, embodied-carbon and weight outputs when you need them.
The NCC is a performance-based code: you can comply by the prescriptive Deemed-to-Satisfy default, or by a Performance Solution assessed against the requirement directly. BTW is built for that second path. We provide the verification data; you achieve the certification.
Independent & product-neutral. AFRC Lab is a third party. We map the method, specify the performance it must meet, train your people and verify the outcome — we don't supply, sell or endorse any product or brand. You procure systems and materials from your own suppliers; our role is to make the result defensible, whoever you buy from.
Send us one window and compare.
We’ll model the actual system to ISO 15099 and show you the result against the default — then you decide.
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