Apparently, studies have shown that determined R-Values have little correlation with how an insulating material actually performs in a non-SIP home. When taking into account factors such as cavity voids, wiring without compression, and paper facer stapled to studs, the actual R-Value decreases significantly.
SIPS homes avoid these familiar problems by distributing insulation uniformly among the entirety of the panels. Without these negative effects, actual R-Value of insulation within a SIPS panel can actually exceed its determined R-Value
Our exterior walls are 4 1/2" SIPS and the roof is 10 1/4". Here is a table from our SIPS manufacturer, Fischer SIPS:
R-Value Comparison to fiberglass:
|Panel Thickness:||Actual R-Value||Performance Value|
Soon, we will post our actual electric bills showing the kw/h per square foot as well.