Double Pane Low E Windows U Factor

Window type u factor ratings.

Double pane low e windows u factor.

Consult specific manufacturers for nfrc rated u factors and shgcs for products of interest. 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. Very hot sunny climates. Double pane with low e.

This figure illustrates the characteristics of a typical double glazed window with a low solar gain low e glass with argon gas fill. Three panes of glass also available on select product lines for increased energy efficiency. The only exception to this rule are roof and skylight windows with low e smartsun glass which offer a u factor of 0 35. Double pane dual pane glass naturally performs better than single pane glass for energy efficiency as the space between each pane acts as an additional layer of insulation from the heat or cold.

Good quality single pane window 1 0. Generally speaking windows all have a u factor between 1 3 and 2 and the lower the number the better. Vinyl frames are low maintenance and provide good thermal insulation. Good single pane with storm window 6.

Blocks 94 of the sun s ultraviolet rays. Two panes of glass with sundefense low e protection and insulating argon between the panes. The u factor will approach the very low 0 15 point if there is a gas such as argon or krypton between the layers of glass glazing. Sections may be hollow or filled with foam insulation.

Old metal casement window 1 3. Gases are heavier than air and therefore provide insulation resistance to air. Triple glazed windows may have a u factor as low as 0 15. Low e glass is optimal for conserving energy because it reduces ultraviolet uv and infrared light penetration to limit heat transfer.

Energy star provides recommended u factors for your climate. Low u factors are most important in heating dominated climates although they are also beneficial in cooling dominated climates. Additionally the window selection tool compares average simulated energy costs for your location based on various window types. Fiberglass frames can be either hollow or filled with foam insulation.

The best high performance double pane windows may have a u factor of 0 30 or lower indicating that they are very energy efficient. 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. Some triple pane windows may have a u factor as low as 0 15. Fiberglass frames are strong durable low maintenance and provide good insulation.

Most windows now carry this rating so it s becoming easy to make comparisons. Blocks 95 of the sun s ultraviolet rays. Double paned windows may have a u factor at or below 0 30. Low e is a microscopically thin and virtually invisible coating that is applied to the side of glass that faces.

Double glazed low solar gain low e glass. Double pane clear and low e.