R Value Calculator

Before

  1. Heating/cooling off for at least 60 minutes
  2. Sun not shining on outside surface
  3. Ideally large inside/outside temperature difference

Steps

  1. Measure temperature of an inside wall, bed head, funiture, ideally facing into room at same height as wall near the wall
  2. Measure the wall/floor/ceiling
  3. Measure outside air temp

Calculator

Surface Type:
Temperature Units:
Inside Ambient Temperature
Inside Surface Temperature
Outside Ambient Temperature
Results
Indoor Air Film Convection Transfer W/K/m2
Indoor Air Film Radiation Tansfter W/K/m2
Indoor Air Film R Value (SI) m2·K/W
Indoor Air Film R Value (Imperial) ft2·°F·15/BTU
Heat Loss (SI)
Heat Loss (Imperial)
Estimated R Value (SI) m2·K/W
Estimated R Value (Imperial) ft2·°F·h/BTU

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