In previous blog posts we have talked about R-Values that measure how effective at blocking Heat Loss the exterior wall of your home. The “R” in R-Value refers to the insulation’s Resistance to heat loss. Therefore, the greater the resistance the better the insulation is performing and that translates to the higher the R-Value the better. High Score wins.
Windows on the other hand are measured in “U-Values.” A U-Value is a measure of how much heat is transmitted through the glass. Therefore, the more heat that moves through the glass is represented in a higher U-Value. Therefore the lower the U-Value for a window the better it is performing. This is a mathematical process that is exactly the opposite of measuring the insulating value of walls and their R-Value.
Yes, we agree it is confusing but once you understand it quickly becomes routine.
A typical “insulated glass” window has two panes of glass and the interior void between the windows is filled with Argon Gas. Argon is widely used as it is a compound that transmits heat very poorly. Think about it, since Argon transmits heat poorly it is therefore exactly what we want. The Vermont Energy Code requirements start at U-Value of 0.30 and lower, remember “Low Score Wins” with U-Values. There are several thresholds that a quality built home in Vermont should have in the windows. Typically a very high quality home will have windows that have a U-Value of U-0.25 which is a significant improvement over required minimums.
Vermont Modular does not install Double Pane windows. We have chosen to upgrade to Triple Pane glass which gives us the ability to fill TWO cavities with Argon Gas to improve the performance of the window even more. Our very best windows will have a U-Value of U-0.15 that represents a huge improvement over typical Double Pane Windows. We caution you, we are now talking about windows in a brand-new home, these are not replacement windows.
We still contend that replacing poor performing windows is not a sensible use of money and/or energy. The amount of energy consumed to manufacture replacement windows out-weighs the environmental gains. Also replacing windows is a poor financial situation.
We believe that installing Triple Pane Windows when the house is brand-new represents environmental responsibility and energy efficiency.