It is well known that ICF far outperforms framed buildings in energy efficiency and comfort levels, but how do we measure this performance? The R- value, or “resistance to heat flow”, measures just that. Using the R-Value home builders can measure the resistance a material has to heat transfer.
Overall, there are 3 main factors that affect the energy performance of a building including it’s radiation/mass, convection and thermal conduction. Out of these three factors the R-Value accounts for thermal conduction which is the transfer of heat by contact of one molecule to the next. In a typical wood frame wall the only component with high R-values is the insulation itself. However, not all the other components score as highly and around every 16 inches these lower level R-values (for example, a stud has an R-Value of R-5) form a “thermal bridge” which allows heat to travel through the walls at a higher rate. This means that around 16% of the total wall area in a wood frame build consists of these thermal bridges, reaching a mere R-7 at most. While builders may advertise the higher levels achieved by the insulation, advertised values can be double what is actually achieved after detracting the thermal bridge effects.
This is where ICF stands out. In the center of ICF walls lay concrete sandwiched between two layers of EPS foam which provide two layers of continuous insulation, eliminating the risk of thermal bridging to occur. The concrete core is slow to change temperature meaning that your buildings temperature will stay consistent throughout the day, regardless of what’s happening outside. Plus your building’s heating or air conditioner won’t have to work as hard. Each side of the EPS foam achieves R-11, meaning this technology typically rates at R-22 or higher!
Interested more in the science that proves this? Check out our next article where we analyze the CLEB study!