Although I grew up in New York and attended college in New England, I have lived in the South for more than 30 years and have become physically acclimated to warmer weather and more accustomed to local building practices. My moderate-climate building experience is what leads me to speak up frequently about the fact that much of the information on GBA, as well as in the building science community as a whole, tends to be cold climate focused.
So it was with some trepidation that I ventured north to Minneapolis in January for a DOE Building America Retrofit Team meeting that I was invited to participate in as part of Verified Green. Having just experienced several days of cold weather and a region immobilized by a cover of ice, I checked the forecast for Minnesota and was not too pleased to learn that it was not projected to be much above zero for my entire visit. I dug out the few pieces of warm clothing I own, which, while reasonably effective at keeping me warm for short periods of time, would have likely led to my quick demise had I been stuck outside for more than an hour or two where I was going. But enough whining about the weather. I was happy to have an opportunity to spend time with my friends Michael Anschel and Chaden Halfhill, as well as Peter Yost, Gary Klein, Ted Cater from Panasonic, and other industry notables.
A great list
Pat Huelman of the University of Minnesota kicked off the DOE meeting with an overview of the project and a quick timeline of the evolution of green building, which succinctly described how each improvement led to problems that were solved by the next improvement:
1. Insulation, which taught us about air sealing;
2. Air sealing, which taught us about moisture;
3. Moisture control, which taught us about ventilation;
4. Ventilation, which taught us about combustion safety;
5. Combustion safety, so we don’t kill our clients.
I like his chronology, and I think it is probably repeated regularly by new entrants into high-performance construction—but it makes me wonder what the next items are on the list, because certainly we aren’t finished learning. Is worker safety the next one? What about product toxicity? Global warming potential? Who knows? But I think it will be interesting to see what’s next and when we figure it out.
Probably the most interesting thing I experienced during my brief foray into the sub-arctic was the amount of ice on the interiors of windows and glass doors, even high-performance multi-paned units. We all know that windows are the weak links in most buildings, but the importance of this tends to be lost on many of us in moderate climates; as long as we limit excess solar gain, we are generally fine. What I learned about cold climates is that in very high-performance buildings with excellent insulation and air sealing, the difference between the overall performance of the window and the rest of the envelope is so extreme that a combination of air movement past the gaskets at window sashes and humidity in the air can cause condensation at the edges of the glass as well as at window hardware. And when it’s well below zero outside, that condensation quickly turns to ice. I am now beginning to understand why northern builders like super-high-performance windows, such as those available in Canada and Europe. When building envelopes are leaky and less well insulated, air and moisture can move back and forth by any path, reducing the amount of condensation and ice on windows. So we may have another unintended consequence to add to Pat’s list. Ultimately, the most important thing I learned from this experience was that I don’t want to live or work in extreme cold climates on a regular basis.
One other cold-climate tidbit I picked up was the suggestion to install a tempering tank for incoming water before it is delivered to a water heater. Since municipal water supplies in the North can sometimes be only slightly above freezing, it was suggested that installing an un-insulated storage tank in the basement to store water before it is heated is a good energy-saving strategy. The tank will allow water to rise from the incoming temperature to the ambient basement temperature—often as much as a 30-degree rise—requiring much less energy to heat the water to 110 degrees in the heater. Sounds like a cool (or warm) idea, but, according to Mr. Anschel, these tanks are not readily available, so plumbers end up buying cheap water heaters and stripping off the insulation and heating elements. Now that sounds kind of strange to me.
Regarding all these cold-climate issues I have raised, I realize that humans are quite adaptable and I would likely become accustomed to cold-climate weather (and construction methods) after a few weeks or months, and I might even begin to appreciate shorter, milder summers. I do think, however, that I’ll stay where I am for the time being. If I decide to move, I’m pretty sure it will be to another moderate climate—most likely not one like Minnesota’s, at least not for the winter. Brrrrr.