EPS R-Value Dominance: Debunking Polyiso Myths

Compare the performance of Polyiso and EPS insulation in retaining R-Values in varying temperatures. Learn how EPS insulation maintains consistent R-Values over time and temperature changes, offering superior thermal performance and energy efficiency compared to Polyiso insulation.

ICA EPS maintains its R-Value

It seems when you have a simple and successful product everyone wants to recreate it. This has played out for expanded polystyrene many times. EPS was developed in the early 1960s. It is a lightweight, inexpensive solution for many applications including insulation. EPS experienced a huge success in the roofing insulation industry in the late 70s and early 80s. With that success, along came the competition. Polyiso came into market with low ball pricing and claims of having a higher R-Value than its white counterpart. Due to marketing and perceived value of Polyiso, EPS roofing insulation business virtually disappeared.

But time tells all and according to several studies, time is not Polyiso’s friend. According to recent studies, Polyiso’s R-Value diminishes not only with time but also with temperature. Polyiso begins to lose its R-Value immediately after it is manufactured. After the manufacturing process of Polyiso, the gases in the pores diffuse out and are replaced with air. Multiple tests done by Building Science Corporation concluded the following: Polyiso samples showed a decrease in R-Value as outside temperatures go below freezing. It appears that the “peak” R-Value for all samples occurs only when outdoor temperatures are closer to the indoor temperature.¹ That certainly isn’t very effective! EPS has been proven to retain its R-Value over time and different temperatures.² EPS is also more user friendly, available in various sizes and densities, plus it is recyclable! You can have it all with EPS, along with the extra money in your pocket, because it still costs less!

We understand wanting to try new products. We understand that some may have thought that more expensive is better. It’s OK, we forgive that. Our diversity “insulated” our feelings as we moved into other endless markets for EPS, the Extraordinary Product Solution. However, now many want to come back. They’ve found out the grass isn’t always greener, pinker or bluer and the ordinary white stuff isn’t so ordinary after all.

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¹ Building Science Corporation – Info 502: Temperature Dependence of R-values in Polyisocyanurate Roof Insulation 4/11/2013
² EPS Below Grade Series 103 11/08
 

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This article was posted on April 26, 2013, by Insulation Corporation of America (ICA) – a Women-Owned manufacturer of Geofoam and Expanded Polystyrene (EPS), which is commonly but mistakenly referred to as Styrofoam™. ICA is located in Allentown, PA and services the entire Mid-Atlantic Region from Virginia to Maine to Ohio.

 

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