Key takeaways
- Low U-factor is the number to watch
- Triple-pane and warm-edge spacers shine in deep cold
- Insulating the frame gap is as important as the glass
Hold the heat in
In cold climates the goal is to keep indoor heat from leaking out. Look for a low U-factor, double or triple-pane glass with an insulating gas, and low-E coatings that reflect heat back inside.
South walls can use a higher solar heat gain to welcome winter sun.
Edges and frames
The edge of the glass is the coldest part. Warm-edge spacers reduce that, and so reduces condensation. Insulated frames such as fiberglass and good vinyl also help.
Check how the sash and frame are built.
The gap around the frame
A great window in a poorly insulated opening still leaks. Filling the gap with low-expansion foam or insulation, and sealing inside and out, is as important as the glass.
Related services
Quick answers
Why do my windows frost on the inside?
Warm, humid indoor air meets a cold surface. Better windows and lower indoor humidity help.
Are casement windows better for cold?
Their tight closing seal helps, but the glass and installation matter more.
Ready to talk it through? Get a free estimate or call 800-224-9245.