Dial in glass type, frame system, cavity fill, and spacer. The four performance metrics (U-value, SHGC, VT, and air leakage) recalculate in real time and check against the specification Catalyst recommends for Step Code 3 / 4 / 5. Those are our recommendations, not code requirements. The Building Code's own prescriptive ceiling is shown alongside. SHGC is an informational design input; the Step Code prescribes no SHGC range. Recommended Catalyst products at the bottom update with the spec.
Build the spec. The performance side updates as you go.
Compared against the specification Catalyst recommends for the Step you selected. The Building Code’s own prescriptive ceiling is shown alongside. They are not the same thing.
These are modelled figures for scoping, not test data. Before anything goes into a permit submission, confirm the numbers against the manufacturer's NFRC report and your energy advisor.
Code ceiling verified Oct 2026 against BCBC 2024 Table 9.36.2.7.-A. Step figures are Catalyst’s own spec guidance.
The code sets a floor, and the Step Code scores the whole house instead of the window. Here is where those lines sit for the window, and where we would draw ours.
A lower U-value keeps the room side of the window closer to room temperature, so there is less cold coming off it when you sit or stand beside it.
Water forms on the inside of a window wherever the surface is colder than the dew point of the room air. That can be the glass, the frame or the sash, whichever runs coldest, so we look at the whole window and not just the glass.
In the illustration, a square metre of window loses about 52 W at the code ceiling, 34 W at our Step 4 line and 25 W at our Step 5 line.
No dollar figures here. Your energy model puts a real number on it for your house, and we are glad to go through it with you.
It scores the whole house with an energy model and an on-site airtightness test, and windows are one input to that model. Since 1 May 2023 the province’s floor for new houses is Step 3, though a city can accept the prescriptive route instead by bylaw. A city can also ask for more, and where it requires Step 4 or 5 for houses, the model route is the only route.
Sources, all from the Province of British Columbia. Code ceiling: BC Building Code 2024, Division B, Table 9.36.2.7.-A, which applies to permits applied for on or after 8 March 2024 (Bulletin B24-04). Climate zones are set by heating degree-days, Appendix C, Table C-2, of the same code. Colder zones carry lower ceilings: 1.61 in Zones 6 and 7A, 1.44 in 7B and 8. Elevation can move a site a zone colder, as Burnaby is listed at 2,735 degree-days in general and 3,100 at Simon Fraser University. Product rule: Bulletin B22-01. Step 3 floor and the prescriptive route: Bulletin B23-01. The Catalyst Step figures are our own guidance for a Zone 4 baseline (the calculator tightens them slightly in colder zones) and are not code requirements. Heat figures are an illustration only: U-value multiplied by a 28 °C (50 °F) difference, 21 °C inside and the Vancouver winter design temperature of −7 °C outside. They leave out air leakage and sun, and real windows vary.
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