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  • MS
  • Guide
  • How much heat is lost through windows?

When building a house, we apply wall insulation and invest in economical solutions that will reduce heating costs. However, this will not guarantee warm compartments, since heat may simply escape through leaky windows.

Good windows should have as low U-value [W/m 2K] as possible. The lower the U-value, the less heat is lost through windows. Heat is first of all lost in the system’s weakest points (not for nothing do people say that a chain is only as strong as its weakest link). Windows’ weak link is their frames.

For comparison - panes that keep heat well have the U-value of 1.0 W/m 2K or lower.

U-value of a single window manufactured by MS beyond WINDOWS can be calculated in the U-value calculator.