Over the years, I’ve had several projects where the specifications called for thermal-break frames, polyurethane core doors, or thermal-break thresholds, but the demand has been very inconsistent. The purpose of these products is to reduce the transfer of exterior heat or cold into a building, to lower costs and improve comfort. I’ve often wondered why they weren’t specified more often for exterior openings – particularly in locations with high fluctuations in temperature.
I’m doing some research on this topic, in an attempt to pull together clear, concise, (correct, + complete) information about when, where, and why these products should be used. The demand seems to be on the increase, so I’m trying to find out what all of the driving factors are, as well as other considerations for energy efficiency – like the required U-value and/or R-value, and limitations on holding open exterior doors or requirements for vestibules to reduce air transfer.