In 1970, when I started in the heating industry, there was a battle going on between the folks who believed in catching and controlling the air in a hydronic system by holding it inside a plain-steel compression tank, and those who thought it was best to catch the air and just get rid of it using automatic air vents and diaphragm-type compression tanks.
There will always be fringe markets for products that use renewable energy to provide marginal heating comfort. These markets survive because early adopters willingly sacrifice superior comfort as the perceived price for using renewable energy.
It’s déjà vu all over again” is a famous quote by the late, great Yogi Berra. I’ve lived this scenario, and I’m betting you have, too. I’m talking about callbacks — the woe of the contracting industry.