Performance of Eco-Panels vs Stick Frame with Spray Foam Insulation

People always ask us how our panels will perform compared to traditional construction, and while we can of course site the comparative R values (our panels start at almost 3x as insulated compared to traditional methods) or we can site testimonials from clients about how their energy bills are 70% lower than they used to be, there is often legitimate confusion as to a final answer since all homes are different, have different appliances, different solar orientations, different patterns of power usage, different window configurations, etc., etc.  Or, people ask us, how much better will one thickness of an Eco-Panels panel compare to a different thickness of panel.  So how to answer?  This past winter/early spring we erected a series of small "structures" using both our panels - having different thicknesses - and also out of stick frame construction with (open cell) spray foam insulation, the latter being a much more common occurance in the green building industry, though still far less common than traditional stick frame insulation.  The stick and spray foam combination will generally outperform the stick and fiberglass combination almost every time, so we could have chosen a worse performing comparison, but those looking to build "cheap" generally aren't concerned about performance in the first place.

These small structures each contained a wireless temperature monitor and were set outside our factory, all arrayed to allow equal exposure to the sun as it rose and fell throughout the day.  In addition to a stick-framed structure having spray foam insulation, we made small structures using our 4.5", 6.5" and 8.25" thick panels.  There were no windows or doors in each of these structures, and by performing our experiment this way we could really focus on how the different wall systems performed compared to each other, without the confusion of different appliances, different window arrangements, etc.  Inside each structure - to simulate a heating appliance - we had a simple night light with a small light bulb that was always left on.  We also had a wireless thermometer outside of any structure and IN THE SHADE of our building (north side, and protected from the rain by a small cover that still allowed air circulation).  By setting up the experiment this way we could track over the period of a work week the temperatures inside our structures as compared to the outside air temp.

Perhaps our greatest regret was not erecting these small structures sooner, so as to see colder temperatures.  I don't think anyone would argue that at moderate temperatures insulation simply is not as important for temperature control (though can STILL have dramatic effects on structural strength, indoor home healthy environments and fire safety), and only during one week - and one night during that week, did we see temperatures fall well under 32 degrees F (0 degrees C).  During that 24 hour period, our 4.5" thick panel structure performed 2.3 times better than the stick-frame and spray foam structure, and our 6.5" thick panel structure performed 3.2 times better than the stick frame structure (so much for our always thinking that additional amounts of insulation had dimishing returns!).  Our 8+" panel structure so far out-performed the stick frame structure as to be "off the charts" ("What, did it get cold outside?  I didn't even notice"), but these panels do take 4x longer to process in our factory than the 4.5" thick panels, so we do not often encourage their sale except to arctic/alpine environments (they are presently in alpine New Zealand and arctic Alaska).  Anyway, without further adieu, here is a summary slide from one of our presentations: