Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed. Always a renegadeI’ve known Bruce since the early 1980s, having met him at various solar conferences. I can remember getting into arguments with him back then about some of his ideas. I recall, for example, him arguing that caulk is a bad idea, and he has always shunned heat-recovery ventilators.Bruce’s strong opinions turned off a lot of people, I think, including editors of the periodicals we all read. So his houses haven’t received a lot of attention. But he keeps at it, and his track record is certainly impressive.Bruce is still building much as he was in 1975, though with a few refinements over the years. And his houses seem to keep working — really well. He’s done informal monitoring of hundreds of these homes, and the New York State Energy Research and Development Authority (NYSERDA) has done more in-depth monitoring of a few of them.Occasionally, weather events have tested his houses. Bruce told me recently that when a 1988 snowstorm knocked out power for three weeks, some of his homes served as refuges, with the owners’ friends or family moving in. The same thing happened with the January 1998 ice storm that knocked out power for up to six weeks in parts of the Adirondacks. What’s ahead?While most of the rest of us, including the building science community, seem to shift their recommended building practices on a fairly regular basis, Bruce’s Adirondack Alternate Energy keeps at it with a system he’s tested for decades. Bruce is getting older, and I don’t know whether others in his company will carry on his vision of low-energy houses when he retires.But his completed projects present a larger and larger collection of case studies of a simple system that seems to work well.While I haven’t always agreed with Bruce, I admire his tenacity. He is indeed a visionary. Bruce Brownell, of Adirondack Alternate Energy, has been creating low-energy, largely passive-solar-heated, resilient homes in the Northeast for forty years — and he’s still going strong. Since 1973, Bruce has built more than 375 homes in 15 states, a third of them in very cold (over 8,500-degree-day) climates. Most require just a few hundred dollars of heat per year.He told me that he’s done enough monitoring to know that even in very cold climates his houses will never drop below 47°F if the power and supplemental heat is shut off. The fact that these houses will never freeze makes them popular as vacation homes; they can be left closed up with no heat all winter without worry.I’m surprised that Bruce isn’t better known. While a few of us hold him up on a pedestal as one of our leading low-energy pioneers, most of today’s low-energy designers and builders have never heard of him. I’ve pondered why that’s the case, and I think it must be that Bruce just rubs some people the wrong way. What makes Bruce’s homes perform so well?His houses are all wrapped with four inches of polyisocyanurate insulation — using two layers with overlapping joints and all seams taped. All six sides (walls, roof, floor) are insulated with this system. Bruce claims this achieves about R-36; I suspect that it’s no more than R-30 — and probably a bit less that than. But because it’s a continuous layer of insulation, not thermally broken by wall studs or rafters, and because it’s fairly airtight, the performance seems to be very good.A big part of the performance comes from passive solar design features (augmented by fans). Adirondack Alternate Energy houses are oriented with a long wall and much of the window area facing south. A small fan pulls air from the peak of the house down through an air-shaft and into a network of pipes buried in a bed of 70-100 tons of sand, providing thermal mass.Heat from this thermal mass radiates upward into the house. Backup heat can be supplied by a wood stove, domestic water heater, boiler, ground-source heat pump, or air-source heat pump.This house air is filtered using a moderately efficient (MERV-8) filter, which removes most dust and other particulates. Bruce doesn’t believe a heat-recovery ventilator is required, and while I don’t agree, it seems from anecdotal evidence he reports that his approach is keeping occupants healthy.Keeping all the wood on the interior of the insulation allows it to dry out, and it sounds like there have been virtually no moisture problems over these four decades. Ice dams never occur, he told me.