Here at Vermont Modular we have repeatedly talked about R-Values that measure the amount of Resistance insulation provides for the movement of heat. The greater the Resistance (R-Value) that translates into less Heat Loss. R-Values talk about the movement of heat. What are U-Values?
A U-Value is a unit of measure that is almost always applied to windows whereas R-Values are thought of when talking about Insulation. Yes, they can be used interchangeably but that seldom happens. R-Values are for Resistance of Insulation and U-Values talk about windows and how windows conduct heat.
A U-Value measurers the performance of windows and how well they transmit heat. So, the lower a U-Value the poorer that window transmits heat. All this is sort of the opposite of R-Values.
When talking about an R-Value a high score such as an exterior wall of R-30 performs well because it Resists Heat transfer; and therefore is good insulation.
When talking about a U-Value a low score for a window is good because the various windows conducts heat poorly. The U-Value indicates how much heat is lost. If you have a window with a U-Value of 0.30 you will have met the Vermont Energy Code requirement for a good window. However, that does not mean you have a particularly good window.
A good window, one that transfers heat poorly, will have a U-Value of 0.21 or lower. Remember when talking about windows it is like golf; low score wins. When talking about insulation a high score wins.
Today’s photograph shows you what you typically can’t see – the three panes of glass in your new triple pane window.
To achieve a low U-Value score of 0.21 or even better it is necessary to use a Triple Pane window. Using three panes of glass creates two sealed chambers where Krypton Gas is used rather than Argon Gas. Argon gas is used in spaces of ½” whereas Krypton is used in spaces of 3/8”. Dense Krypton Gas transmits less heat than does Argon. Hence a Triple Pane window performs much better.
Whether you live in Mendon, Vermont or Morgan, Vermont it is a great idea to build your new home with high performing windows. Vermont Modular uses Triple Pane windows all the time!
So, don’t confuse R-Values and U-Values! Be sure your home is highly efficient!