Although I’ve worked with hydronic heating for four decades and designed systems around just about every possible heat source, I would be hard-pressed to predict what might be available as hydronic heat sources 25 years from now. Fifty years from now, I doubt that I will be predicting anything, and yet, hydronic heating, in some form, will hopefully still exist. If comfort, efficiency and lasting value, rather than only first cost, become established as the market “drivers,” hydronics might even be the dominant method of heat delivery. Imagine that.
By the latter half of the 20th century, the North American hydronics industry got used to the fact that some hydronic heat sources could last for several decades. It was not uncommon for a properly-applied cast-iron boiler to have a useful life of 30-40 years. These boilers usually became technologically obsolete before they were incapable of operating due to some major failure. This was just fine when fuel prices were reasonably cheap and stable, and product development occurred at a somewhat slower pace compared to today. Back then, most North Americans cared little about the “box in the basement,” provided that it responded when the dial on the T-86 got turned up in the fall.
