Windows play several important roles. Basically, they help in filtering out sunlight and air, even as they allow them to enter through it. Without windows, your rooms would without doubt be a little dark, uninteresting, and dingy. Windows come in many types including single pane windows, double pane windows, wooden shaft windows, vinyl replacement windows, aluminum windows, etc. etc. Windows are definitely a basic necessity of any home, especially if you are living in an area with extreme weather during winter and summer.
However, it is quite unfortunate that many homeowners are still using older windows which are inefficient. They have not yet discovered the true value of energy efficient windows. Windows are heavy consumers of energy. An average American home may lose about 30 percent of heating and cooling energy through windows. Energy efficient windows save a lot of money on monthly utility bills. In fact, some new replacement windows have been designed in such a way that they gain energy instead of losing it.
If you are building a new home, their higher purchasing costs can be offset as you will probably require a smaller, less expensive air-conditioning system. Your choice of window can have a significant impact on monthly utility bills. Windows gain or lose heat by means of radiation, convection, conduction and air leakage. This is referred to as heat transfer and is expressed with U-factors or U-values. U-values are opposite or converse to R-values. Thus, a U-value of 2 is the same as an R-value of 0.5 0r 1/2. Not like R-values, the higher the U-values, the better. In other words, higher U-values have better insulation.
Conduction is the transfer of heat through a solid, such as metal. Most of the heat is lost through windows via conduction. With less conductive window frames, such as wood and vinyl, you slow down heat flow. Double or triple pane windows are filled with nonreactive gas, such as Argon and Krypton between panes of glass. This helps to reduce heat flow, as well.
Radiation is the transfer of heat from a warmer place to a colder place. For example, if you stand near a fire, you’ll get a warm feeling on your body. On the contrary, your body feels cool when it radiates heat when taking a cold shower.
Air leakage through windows accounts for a huge percentage of heat loss through windows. Modern replacement windows have great features that efficiently stop the loss of heat through conduction, convention, radiation or air leakage.
Double pane and triple-pane glass windows are known for their superior insulating values. And combining double-pane or triple-pane windows with low-E coatings boosts energy efficiency considerably.