Head to Head Heat Test: EPS vs GUTEX vs Mineral Wool

Head to Head Heat Test: EPS vs GUTEX vs Mineral Wool

It’s Hot Outside! (and getting hotter) GUTEX is Superior Summertime Thermal Insulation

Building insulation has been largely driven by cold climate performance concerns. We typically ask “What’s the R-Value?” to figure out what the heat loss will be to the outside and how big our heating systems will need to be to stay comfortable in winter.

But today, in a world experiencing ever greater extreme heatwave events, where stepping outside in daytime is like stepping into an oven on broil, there are other factors critically important in providing thermal comfort and performance: the insulation’s specific heat capacity - the amount of heat energy required to raise the temperature of material per unit of mass; and the decrement factor - or the delay (time-lag) between peak temperature of the outer surface and the resulting peak temperature at the interior surface.

GUTEX wood insulation (board or dense-pack) has a much higher specific heat capacity and decrement factor than foam, mineral wool or fiberglass. It absorbs much more heat, stores the heat longer and better dampens the flow of that heat to the interior space, so on summer days when the building enclosure is getting blasted like a brick in a firing kiln, occupants are cool and comfortable.

Graphing The Performance

Below, the graphs show this time-lag dynamic using 7” of GUTEX THERMOSAFE. The peak outdoor temperature occurs at about 2pm, 70 degrees F above the low temperature at about 3am. Yet the peak temperature at the interior surface of the GUTEX THERMOSAFE occurs 10 hours after the outdoor peak, just after midnight, and only rising 5.5 degrees F.

The 10 hour time-lag demonstrated by GUTEX THERMOSAFE

See For Yourself

Here’s a quick video we made in the 475 office of the GUTEX heat buffering demo box. Head to head: EPS vs GUTEX vs Mineral Wool

GUTEX is safe, natural wood fiber insulation with thermal and acoustic properties that performs better than other insulation types to optimize occupant comfort while saving energy and reducing the carbon-intensity of your building. In just 7 minutes of heat, GUTEX shows how drastically equal levels of insulation can perform. GUTEX buffers the heat better to keep temperatures stable and consistent throughout the building.

To include GUTEX on your next project, start with a free quote: