Calculating R-Value and Heat Loss Using FLIR ONE PRO And Surface Temperature
Seeing all the missing insulation in my roof had me wondering if I could use my thermal camera to estimate heat loss. A quick google search found this smart guy's post Measuring your house walls R-value with an infrared thermometer with the calculations. The maths are beyond me, but lets see if I can figure it out. Temperature Gradient For a given internal ambient temperature and a given outdoor temperature the temperature drop for each different material is proportional to the materials R Rating. e.g. 68F indoor to 8F outdoor is 60F delta T. The total R rating is 13+6=19. So the drop for the R-19 material will be 13/19*60 = 41F. Now what if we don't know one of the R Ratings but we do know the temperature drop? Indoor Air Film Air is a good insulator and the approximate indoor air film for stable air is R0.14 or U7.14. This is the air between your indoor wall and yourself. The U value is made up of radiation of around U5.1 and conduction/convection of around U1-3. A s...