Performance isn’t all about R-value, but that is a big piece of it
Polar’s insulation products get their thermal performance from air pockets that are formed inside polystyrene beads. Picture bubbles in a balloon. The beads are fused into durable blocks that are then cut into sheets and laminated. The air trapped in the beads provides the thermal resistance.
Polar’s products maintain thermal performance throughout their installed lifetime. That isn’t true of all rigid insulation products. That’s because many others rely on low density blowing agents to enhance R-value. Low molecular density gases slow thermal migration by lowering conduction and convection – fewer molecules interacting with one another – thereby raising R-values. However, those same gases are highly diffusive and tend to be replaced by higher density air – which in turn lowers the R-value – it’s called thermal drift. This is why you see heavy foil facers laminated on some rigid insulation, to trap the gas, but over time it is still displaced, and what happens when you cut it?
Polar’s products begin with air in the cell structure so there is no thermal drift, and with Polar you aren’t paying a lot (stress lot) extra for low density gas that will be lost or the expensive laminates used to slow the inevitable diffusion.
Water and Water Vapor
Fusing beads of polystyrene into rigid boards creates insulation that has an integrated network of microscopic voids – interstitial spaces – at bead boundaries; like the spaces between marbles in a jar. The result is insulation that is vapor permeable, an important characteristic in many above grade building insulation applications.
The size of the interstitial space is so small that the board is inherently resistant to liquid water absorption. Water resistance is helpful for below grade uses.
Trends in building design are calling for tighter structures. Better sealing of traditionally leaky areas helps improve thermal efficiency and reduces energy requirements. At the same time they are lowering the number of hourly air exchanges that had prevented moisture accumulation. Warm moist environments are particularly well suited to mold growth. Polystyrene provides no nutrients to support mold, and because it is vapor permeable it helps reduce moisture potential.
Long Service Life
Polystyrene insulation maintains its thermal performance throughout its life. It won’t breakdown, decay or settle like other insulation materials. Long term durability ensures long value and is one more reason for its popularity.