Double Pane Low E Windows U Value

The more panes the better right.

Double pane low e windows u value.

Low e coatings usually applied to the inside layers of insulating glass manage the amount of light and heat either conducted through a window or reflected away from it. Additionally the window selection tool compares average simulated energy costs for your location based on various window types. High performance double pane windows can have u factors of 0 30 or lower while some triple pane windows can achieve u factors as low as 0 15. Triple glazed windows may have a u factor as low as 0 15.

Triple pane windows work best when enhanced energy performance is a key objective. Double paned windows may have a u factor at or below 0 30. Gases are heavier than air and therefore provide insulation resistance to air. The best high performance double pane windows may have a u factor of 0 30 or lower indicating that they are very energy efficient.

For most energy efficient windows the u factor for the entire window assembly is higher than the u factor at the center of the glass. Energy star provides recommended u factors for your climate. Very low emissivity windows offer the best improvement you can obtain in window insulating performance. Low e windows have u value and emissivity values that range from 0 02 to 0 20 which means that 80 to 98 of the room s heat is reflected back into the room in the winter.

Some triple pane windows may have a u factor as low as 0 15.