More observations on Thermal Mass and ICFs

Last week, we posted a video in which NUDURA’s Gary Meine explained how Thermal Mass works, with respect to Insulated Concrete Forms.

We got a comment from one of the world’s leading thinkers on the topic of energy-efficient residential building: Harold Orr, Saskatoon-based engineer, who helped pioneered the Passive House concept in Canada, many years ago. Mr. Orr was recently named to the Order of Canada for his work.

Thermal mass is a benefit but it is most effective when there is no insulation between the mass and the space you want to keep at a constant temperature. In fact if all the insulation value were on the outside of the wall instead of being split between the inside and outside the thermal mass would be much more effective. The more insulation you have on the outside the more effective it becomes.
Harold Orr

NUDURA’s Gary Meine replies:
Correct, Howard, to optimize the thermal mass of a wall the insulation can be moved away from the conditioned side. We do have a form which can create a wall like this, the One Series. The One Series form lineup allows for there to be insulation on one side of the wall and exposed concrete on the other. You can see images of this on our website. This does not discount that the traditional ICF is still a wall of Thermal Mass. The concrete is sandwiched between two layers of EPS foam. By doing this, traditional ICF’s get the benefit of a mass wall and at the same time allow for easy installation of electrical and interior finishes without the additional steps of furring or framing additional walls that a concrete would require. Building codes do recognize an ICF wall as a mass wall.