U-factor


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U-factor

Measure of the heat conducted through a given product or material—the number of British thermal units (Btu) of heat that move through a square foot of the material in one hour for every 1 degree Fahrenheit difference in temperature across the material. U-factor is the inverse of R-value.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

thermal transmittance, U-value

The time rate of heat flow per unit area under steady conditions from the fluid on the warm side of a barrier to the fluid on the cold side, per unit temperature difference between the two fluids.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Both measures concentrate on enhancing the fenestration assemblies, including enhanced U-Factor and Solar Heat Gain Coefficient (SHGC).
Walls and attics are rated with R-value, and windows are rated with U-factor.
Simplified one-dimensional thermal models were developed to compute heat transfer and temperature distribution in TDD glazing panes, as well as the overall thermal performance characteristics (SHGC and U-factor) under standard or design environmental conditions.
U-factor, the better the window is at preventing heat transfer through the window.
Take for example a window's U-factor. It is used to measure its ability to conduct heat.
The curtainwall provides enhanced condensation performance and tow U-Factor, along with panoramic, floor-to-ceiling views.
Specific guidelines for U-factor and solar heat gain coefficient (SHGC) of replacement glass; minimum R-values for insulation; exemptions for lighting replacements of less than 50% of a space, as well as bulb and ballast-only lighting alterations, so long as these don't result in increased power consumption; and requirements for door and roof replacements, as to when additional insulation is mandated, and when it is not.
This incentive includes replacement windows and doors, including sliding glass doors, with a U-factor (a measure of the amount of heat that escapes from a room) and a Solar Heat Gain Coefficient (a measure of the amount of heat allowed to enter a room) each at or below 0.30.
The National Fenestration Rating Council is a good first stop, since o it rates windows on factors like air leakage and offers a U-factor measurement of how well the window guards against heat loss.
When selecting windows, consider their insulation value (the U-factor) and the solar heat gain coefficient (SHGC.) Advanced spectrally selective coatings allow light in, but not heat.