Triple pane or double pane: which does a mid-Island house need?
Triple glazing is sold hard, and sometimes it's the right call. Here's what a third pane actually changes in a Nanaimo or Duncan winter, what it costs extra, and which walls are worth it.
What a third pane does
A double-pane window is two sheets of glass with a sealed, gas-filled space between them. Triple pane adds a third sheet and a second sealed space. That does three things, in order of how much you'll notice them here:
- The inside glass is warmer. On a 2°C night the room-side pane of a good double unit is cool to the touch; the triple is closer to room temperature. That's the difference between a chair you avoid in January and one you sit in.
- Less condensation. Warmer glass means moisture in the room air is less likely to condense on it. If you wipe the frames every winter morning, this is the fix you're actually looking for, along with running the bath fan. More on our condensation page.
- Lower heat loss. Real, but smaller than the brochures imply, because our winters are the mildest in Canada. The heating saving over a good Low-E double pane is modest; over 1980s aluminum single or early double glazing, either option is a big step.
Where triple pane is worth it on the mid-Island
- North and east walls that never see winter sun and run coldest
- Big glass: picture windows and patio doors, where the cold surface is large and you sit near it
- Bedrooms, where you're still and the air is humid at night
- Homes with a condensation or mould problem on the frames
- Homes heated by a heat pump running at a steady low temperature, where a warm glass surface makes the room feel finished
Where double pane does the job
- South and west walls that get winter sun
- Windows under a wide eave or deck roof
- Garages, workshops, and rooms you don't sit in
- Small windows, where the extra pane changes little
Most houses we quote end up with a mix: triple on the two or three walls that need it, double everywhere else. We quote each window on its own line, with both options where it's a real choice, so you decide wall by wall and don't pay for triple where it adds nothing.
Noise is a separate question
A third pane helps a little, but the things that quiet a window are mass, the width of the air space, and two panes of different thicknesses or a laminated pane. A double unit built for sound can out-perform a standard triple. If one side of the house faces the highway, the Island Highway, or a school, say so at the measure and we spec that side for sound rather than pane count. See drafty windows for the other half of the noise story, which is usually the frame, not the glass.
Glass and coatings
Every window we install is Thermoproof, built in Cobble Hill with Low-E sealed glass. Low-E is a thin metallic coating that reflects heat back into the room in winter and keeps solar heat out in summer; it does more for a mid-Island house than the pane count does. Thermoproof's SunSmart™ range offers eight coating options, and we match them to the wall: more solar gain on a shaded north wall, more shading on a west wall that cooks in August. More on the Thermoproof page.
FAQ
Common questions
Is triple pane worth it on Vancouver Island?
Sometimes, and not for the reason most people expect. Our winters are mild, so the heating saving from triple over good double is modest. Where triple pane earns its keep here is comfort and condensation: the inside glass stays warmer, so you can sit beside it in January and the frame stops sweating. North walls, big glass, bedrooms and homes with a condensation problem are where we recommend it. A south-facing window under a deck roof usually doesn't need it.
How much more does triple pane cost?
More than double pane, window for window, because there's a third pane, a second sealed air space and a heavier sash. How much more depends on the window size and style, so we price both on the quote where it's a real choice and let you decide wall by wall.
Does triple pane cut noise?
Some, but the pane count matters less than people think. What quiets a window is mass, air space, and glass of two different thicknesses or a laminated pane. A double-pane unit built for sound can beat a standard triple. If one side of your house faces a road, tell us at the measure and we'll spec that side for sound.
Do I need triple pane for the BC rebate?
No. The Home Renovation Rebate asks for program-qualified products, and many double-pane Low-E windows qualify. We confirm which windows on your quote meet the program before you order.
Will triple pane stop condensation on my windows?
It helps a great deal, because the room-side glass is warmer, so moisture in the air is less likely to condense on it. If the house itself is humid (no bath fan use, drying laundry indoors, a crawlspace with no vapour barrier), some condensation can still appear, and we'll tell you about that at the measure. See our page on condensation on windows.