Steady Wins the Performance Race
In high school, I remember watching the track team race around the track. One runner Peter, a farm kid, was fascinating to watch as he always grabbed the early lead. Peter always looked so fast but in the end he would typically finish in 3rd or 4th place. In that moment, early in the race, Peter looked like a world class athlete that would easily win gold at the Olympics. In those early moments, that frozen time, the measure of performance was perfect.
Thirty-six years later and I see the same thing happening in the rigid insulation market. Its like watching Polyiso, and XPS insulation running just like Peter, getting off to a tremendous lead regarding R-value, but then fading out at the end. That perfect moment in time is when that R-value gets measured and they look like superheroes but in reality they just “blowhards.” Pardon the pun as the blowing agent escapes and lowers the r-value. (LEARN WHY)
When it comes to below grade or roofing insulation, Polyiso and XPS start out with really good R-value numbers but they don’t last (LEARN MORE). Unfortunately, you pay for these early performance numbers, sometimes as much as 50% more. Paying for performance isn’t bad but not knowing that the product will fade out is a different matter.
The old idiom, “slow and steady wins the race” really holds true in insulation. EPS might start out slow (or lower r-value) but is consistent through its life and ultimately wins the race. Not only does EPS (Expanded Polystyrene) have a steady consistent R-Value but when compared with XPS and Polyiso, it also performs better in the field. XPS and Polyiso, when wet, hold the moisture and loss much of its r-value. EPS has the ability to hold its r-value and even expel moisture under exsiccate conditions.
Next time, when you’re looking to specify or install insulation on a project, remember that Polyiso and XPS look great at the beginning but EPS is the steady performer and the best value in rigid insulation. Your customer deserves the winner - EPS.
Value Engineering - A Win-Win Strategy
Experience in the industry has shown that it takes designers and architects several years to catch up and change their project specifications based on new information. This opportunity window allows for roofing contractors to provide a wonderful service and offer "Value Engineering." (Get a copy of - "Value Engineering Tips and Tricks for Roofing")
The recent research has shown that polyisocyanurate (ISO) insulation provides an R-value of 5 R/inch at 40ºF and 4 R/inch at 25ºF. Contrast that to Type VIII Expanded Polystyrene (EPS) that has an r-value of 4.2 R/inch at 40ºF and 4.4 R/inch at 25ºF. Now, take into account that the cost difference between ISO and EPS insulation. ISO Insulation can cost up to 60% more. This really spotlights EPS as the best r-value/inch value. Substituting EPS insulation in for ISO in a value engineering premise is quite simple as the numbers speak volumes. The real trick is how it can be accomplished in an environment that is so "Pro" ISO?
Ultimately, the building owner can win by saving money and yet the contractor can win by proving his professionalism and closing more work - a real Win-Win.
LTTR - What does long-term R-value mean
Early this year, the National Roofers Contractors Association, made a recommendation to it's members that Polyisocyanurate Insulation revise "its design in-service R-value recommendation to 5.0 per inch thickness." This declaration was the second time Polyisocyanurate's R-value was downgraded in the last 2 years. For some of us "Energy Aficionados," who understand the principles of insulation off-gassing, determined it was time to re-examine LTTR testing (View Technical LTTR Bulletin).
LTTR really looks at Long-Term Thermal Performance of insulation as 5 years. Do we expect a building to last only five years? How is 5 years a true quantitative analysis of R-value performance?
We do not replace insulation in a building every 5 years, why would we think that is long-term? Most building in the U.S. are built to last 50 years, some 100 years. Long-term R-value should be figured at 50 years… right? We know off-gassing continues to happen after 5 years. Let's re-evaluate what we are doing as an industry and modify Long-Term Thermal Resistance to at least 50 years.