Exterior Door U Values

A 2 1 4 inch solid core wooden door for example has an r value of 3 70.

Exterior door u values.

Fire doors are usually rated for 20 or 90 minutes. U factor is the rate at which a window door or skylight conducts non solar heat flow. Therma tru recommends that consumers consult their tax advisors and review irs guidance prior to purchasing any door product. Current legislation requires that all new doors sold and fitted in england wales must have a u value not exceeding 1 8w m2k and the lower level of 1 6w m2k applying in scotland.

There are two basic terms that refer to the energy efficiency of a window or door. Rochester patina 1 2 lite unfinished smooth left hand fiberglass prehung front door with sidelites model 873190 3a4 139. It s usually expressed in units of btu hr ft2 of. The r value of a 1 3 4 inch wood door is 3 03.

Feather river doors 63 5 in. For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09. The fire door rating measures how long a door can prevent the passage of flame from one side of the door assembly to the other. The r values of most steel and fiberglass clad entry doors range from r 5 to r 6 excluding a window.

For further details on the residential energy efficiency tax credit visit the irs website. For example a 1 1 2 inch 3 81 cm thick door without a window offers more than five times the insulating value of a solid wood door of the same size. Let s begin with the r value and u value of windows. Therma tru offers a wide selection of fiberglass 20 minute fire rated doors for protection with a sense of style.

U value has an inverse relationship to r value. The rating your door will be influenced by its glazing content. For windows skylights and glass doors a u factor may refer to just the glass or glazing alone. Energy star and the energy star mark are registered trademarks owned by the u s.

The u value of a door is a measurement of its energy efficiency the lower the value the more. R values climb as thickness of the material increases. Nfrc u factor ratings however represent the entire window performance including frame and spacer material. Window and door r values are common questions that arise when purchasing replacement windows or adding a new barn door or front door to your home that has glass in it.

0 56 to 1 13 w m2k which is high compared to other doors but low compared to well insulated walls and attics with many inches of foam or mineral wool or other insulation material in their assemblies.