09/04/2026
— Prescriptive R-Value vs. Performance —
There are many situations where general contractors/homeowners want you, the insulation contractor, to provide a solution to meets the prescriptive r-value thats specified for the relevant to the climate zone where the project is being built. Not that there is anything wrong with installing what is prescribed. But what if you can achieve the same result with a solution that costs less money?
This is where performance comes into to play. Using spray foam for an example, we all know that spray foam is a premium insulating material. It’s not always the cheapest, but a very good product thats’ r-value doesn’t accurately reflect its performance. Now say the job is calling for an R-38 on top and an R-19 insulation in the walls. Does that mean the only way to meet code is to apply almost 12” of open cell in the roof and nearly 6” in the walls? It is one way (an expensive and excessive one), but not the only way to have an efficient and comfortable home or business. With spray foam being an excellent air barrier, that performance factor gives it an edge other insulation materials. Stopping air infiltration is very important in the overall insulation envelope of a structure. So how do we figure out how much foam is really needed to perform at or above the prescribed r-value that meets code? There are multiple companies that can assist in this process giving you the performance data on each job to give to the owner/general contractor. One that we often recommend is a company named Ekotrope. Their software allows you as the contractor to have the data to show your customer exactly what is needed for the home to perform to meet or exceed the prescriptive r-values and even being able to see projected energy costs with each option of insulation/weatherization combinations.
Prescriptive R-value is not the wrong solution, but by learning about and leaning on performance data you’ll be able to provide options often at a lesser cost with the same results. This allows you as the contractor to offer options to save them money by giving them no more than what they need and in turn give your company more job opportunities by providing them the data to show that you aren’t just making educated guesses.
Here is an introductory video about Ekotrope for more info!
YouTube
Learn some of the basics for one of the most widely used software p...
