With a quality double glazed unit approximate u values are 1 2wm2k or alternatively a window energy rating wer of a.
Sliding door u value.
Shgc measures how well a product keeps out solar heat.
The range is from 0 to 1.
Andersen doors and windows that use low e4 and low e glass have a u factor between 0 27 and 0 30.
The label shows the solar heat gain coefficient shgc and u factor for the door.
Access the full energy star most efficient certified products list in excel excel 57 kb.
Look for a low shgc in a climate that mainly requires cooling and a high shgc in a climate that requires heating.
This tool provides some of the most common options on windows and doors and related nfrc certified values.
1 insulated glass can reduce the u factor by up to 40 by better preventing interior heat from escaping to the outside.
Doors lose heat to the outside in the winter and gain heat from the outside during the summer.
For windows skylights and glass doors a u factor may refer to just the glass or glazing alone.
To access those tables select the individual product of interest and scroll down to the professional resources section.
U values are used to determine the insulating efficiency of the window and all of its components.
Look for a low u factor.
Colder climates want a low ufactor 52 to resist.
These sliding glass patio doors represent the leading edge in energy efficient products this year.
The u value is a measure of heat transfer across a building material.
Most efficient recognizes a subset pdf 701kb.
Products that use low e4 and low e glass include certain 200 series fixed units and tilt windows 400 series gliding windows roof windows and skylights and several models of andersen architectural window.
The range is from 0 00 2 00.
Energy performance data for select combinations of options is available in table format on each product page.
U factor is the rate at which a window door or skylight conducts non solar heat flow.
It s usually expressed in units of btu hr ft2 of.
Illustrations of all energy star window types.
This is different than r value that would be used to determine the energy efficiency of just the window pane thus a window with a u value of 1 is more energy efficient than an window with a u value of 5.
Nfrc u factor ratings however represent the entire window performance including frame and spacer material.