Exterior Wood Door R Value

The higher the r value the greater the insulation performance.
Exterior wood door r value. For comparison with. The r values of most steel and fiberglass clad entry doors range from r 5 to r 6 excluding a window. The higher the r value of the energy efficient entry door the better the insulation. R values climb as thickness of the material increases.
R value measures how well certain building insulation materials can resist heat. Many of these doors are remarkably like real wood and may have a thick polyurethane or other foam core a feature that boosts their insulating value. The r value of wood varies by wood density species moisture content. 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.
In new homes especially in cold climates in very energy efficient buildings. A 2 1 4 inch solid core wooden door for example has an r value of 3 70. The r value which is a measure of thermal resistance. 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. For example the typical r value of a six panel wood door is a two whereas a fiberglass door system may have an r value of 10 or 12. The r value of a 1 3 4 inch wood door is 3 03. Even though it seems worse than other materials because wood has a lot of mass it actually can store energy not just prevent the ingress or egress of energy which is only what r values measure.
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. R value for solid wood doors this is a reprint of a recent article on some studies done to show that the straight r value of solid wood is misleading.