The Individual Gas Constant depends on the particular gas and is related to the molecular weight of the gas. Fourier's Law gives us the rate of heat loss through conduction: U = thermal conductance, BTU / (ft2) (FÂº)(hr), ÎT = temperature difference (T1 -T2), FÂº. INSULATION R-VALUES & PROPERTIES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. What kinds of construction and production techniques worked well and which did not? This calculator is now available as a fully featured Android app, work out R-Values on the move and share - search for R Value Calculator on the Android Market. In the SI system the most common units are J/kg K. Unit conversion: 1 J/kg K = 5.97994 ft lb/slug °R… Thanks Fernando, ON Mon, 20 Jan 14, 11:04am probably from United Kingdom Reply to this comment. WHAT IS THE R VALUE THROUGH A 2 X 4 WOOD STUD AT THE 3 1/2 INCH ? Here's the values from Wiki: The conversion between SI and US units of R-value is 1 h•ft²•°F/Btu = 0.176110 K•m²/W, or 1 K•m²/W = 5.678263 h•ft²•°F/Btu, ON Mon, 6 Feb 12, 11:32am probably from United Kingdom Reply to this comment. ON Mon, 22 Jan 18, 1:41pm probably from Afghanistan Reply to this comment. There is an imperial and metric switch you can use for this. Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver, We don't save this data. Doesn't work! The value is independent of temperature. energy efficiency, sustainable development, passive solar, insulation, buildings. If I'm really list the materials used in the wall or roof, tell me what the thermal conductivity is, let me enter the thickness. What's in your wall? 28, No. How did people use different kinds of spaces in their homes? The R-Value calculator is best used as follows: Remember, the values calculated here should be taken as a rough guide, as certain materials (i.e.