High R Value Exterior Doors

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High r value exterior doors.

Some of the features that help therma tru doors earn their energy star qualified ratings include. Rails and stiles these are the horizontal and vertical parts that brace a wood door. Most therma tru decorative as well as privacy and textured glass is triple pane for reduced heat flow. Feather river doors 63 5 in x81 625in mission pointe zinc 3 4 oval lt unfinished smooth right hd fiberglass prehung front door w sidelights model 182191 3a4 70.

A polyurethane foam core. The r values of most steel and fiberglass clad entry doors range from r 5 to r 6 excluding a window. Therma tru fiberglass doors have a solid polyurethane foam core which is among the most energy efficient door materials available today. Rustica s french style sliding barn doors entry doors and rustica s replacement windows have the most efficient r value on the market listed at 3 94 for interior doors and replacement windows and 5 31 for a 2 1 4 exterior door.

This is a huge difference and essentially comes down to astm c518 being a theoretical maximum based on a steady state thermal test of only a portion of the door panel. 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. An insulated steel or fiberglass will have an r value that is twice as good generally r 5 to r 6 but in some cases as high as r 7. The higher the r value the greater the insulation performance.

A 2 1 4 inch solid core wooden door for example has an r value of 3 70. European manufacturers of passivhaus certified doors advertise r values as high as r 11. R value measures how well certain building insulation materials can resist heat. Look for a door with a good insulation value say a u value of at least 0 2 that is r 5 metric.

When determining how much insulation you need don t guesstimate calculate. In new homes especially in cold climates in very energy efficient buildings look for the best performance doors possible. The r value of a 1 3 4 inch wood door is 3 03.