Whistler is hard on windows. Long heating seasons, heavy snow and big mountain views all pull in different directions. Before choosing a product, it helps to know exactly what the Resort Municipality of Whistler requires, because that sets the performance bar.
What Whistler requires, confirmed in September 2026
We asked the RMOW building department directly. Their answer, from a Building Official in September 2026:
- Since January 1, 2024, new Part 9 single family homes must meet BC Energy Step Code Step 4. The requirement is in Part 28 of the Building Bylaw.
- If you use the in-ground basement floor area exclusion, the home must meet Step 5 instead.
- The RMOW Snow Load bulletin (Version 2.0) still applies. It refers to the 2018 BC Building Code, but the RMOW confirmed the requirements are unchanged; the document has simply not been updated yet.
The same Part 28 also sets the emissions requirement: new Part 9 buildings must meet emissions level three (EL-3) of the Zero Carbon Step Code, clause 28.1(f) of Building Regulation Bylaw No. 2482, 2025.
Why the basement exclusion changes your windows
The in-ground basement exclusion lets part of the basement floor area sit outside Whistler's floor area cap, and it can be worth more than the extra units the new rules allow. Our Whistler lot calculator shows what it is worth on your parcel. But taking it moves the whole house from Step 4 to Step 5, a tighter energy target. Windows are a large part of meeting it, so decide early whether you will use the exclusion, and specify windows with that target in mind.
How Step Code treats windows
Step Code is a performance target for the whole house, checked with energy modelling and an airtightness test. It is not a checklist of products, and no single window number guarantees compliance. What matters is the value for your actual windows, in your actual sizes, working together with the walls, roof and mechanical systems. Ask your energy advisor what window value the model needs, then ask suppliers to confirm it for your sizes.
Snow and big openings
Snow load drives the structure. The roof, and the framing that carries it over large glazed openings, are engineered to the RMOW snow load requirements. Plan big windows with your engineer early, because a wide opening under a heavy snow roof needs a header sized for it.
Choice 1: thermal-break aluminum, imported directly
Eurohouse imports thermal-break aluminum windows and doors and triple-glazed systems directly from European and overseas manufacturers, so there is no dealer margin in the price. Aluminum frames suit large glazed openings and contemporary mountain homes. Our European kitchens and windows page for Whistler has the details.
Choice 2: wood/aluminum-clad windows from Baltic Windows
For wood inside and a durable aluminum exterior, one of the window makers we work with is Baltic Windows. Three of its clad lines are relevant in Whistler:
- SCA68: outswing casement, NAFS-rated, available with triple glazing at about 1.0 W/m²K or better, depending on size. Baltic calls it "Alpine Rated": this is Baltic's own designation for mountain and cold-climate use such as Whistler, not a third-party certification. Baltic describes it as ideal for log homes and timber cottages.
- MD78: tilt-turn, triple glazed. Independent thermal modelling by Layton Consulting in Vancouver gave it a U-value of 0.94 W/m²K.
- Slim LN97: tilt-turn, triple glazed, with a flush (coplanar) interior for a minimalist look. Typical values are around 0.8 W/m²K, depending on size.
Baltic recommends triple glazing. Its double-glazed units typically sit around 1.44 W/m²K.
How to choose
- Style: aluminum for large, contemporary glazing; clad wood for a warmer interior and a traditional or timber look.
- Target: Step 4, or Step 5 if you take the basement exclusion. Choose the window after you know which.
- Proof: ask whether each value is tested, modelled or certified, and for which window size.
- Timing: ask for the lead time from shop drawing approval and the deposit terms. Whistler's building season is short, so order windows as early as the design allows.
Talk to us
Eurohouse builds custom homes in Whistler and across the Sea-to-Sky corridor. If you are planning a new home, we can help you set the Step target, weigh the basement exclusion and choose windows that meet both.
See our Whistler custom homes work, or ask about your project. Your first meetings are free.
Call 604-728-5682 or email info@eurohouse.ca.