|My earliest memory of hydronic radiant heating systems dates back to when I was a young child visiting my grandparents' apartments in Chicago during the late 1960s and early 1970s.
My maternal grandparents lived on the second floor of what could perhaps be best described as a duplex. Its age is unknown to me, but it certainly dated back to a period before the common use of a liquid or gas fuel for heat. The coal delivery chute was still evident and leftover coal could still be found here and there in the rear parking area. What fuel was used to provide heat during that period also escapes me. It might very well have been home heating oil, as I seem to recall seeing a truck out back one day making a delivery, but then my memory as a young child is limited to the point that I might just be remembering the home heating oil delivery trucks that were not at all uncommon driving around on the streets at the time.
However, I do remember clearly how the heat was delivered. I can easily remember the silver painted radiators that would make any number of interesting noises while cranking out an enormous amount of heat. The same can be said for my paternal grandparents' apartment. While it was a much larger brownstone with more units, further hiding the initial source of the heat from a young child interested in such things, that heat was still delivered using a radiator. There were the same interesting noises, and the same enormous amount of heat.
Now, living in Chicago, particularly in the winter and particularly during a time that encompasses the blizzard of 1967, there are worse things than having too much heat. But, the ancient systems serving these buildings with their cast-iron, steam heated radiators (likely single pipe and difficult to balance) did not really provide anything that could allow for a finite adjustment of the temperature. And, in speaking with our graphic designer who lives in a similar city apartment, such antiquated systems still cause issues. The end result was often an all-or-nothing proposition and it was not uncommon to just settle for a reasonable setting on the hotter side and go with that. I can clearly remember many a day where the weather would be frigid on the outside, but uncomfortably tropical on the inside. Windows would sometimes be opened to temporarily relieve the excess heat, which obviously is not an efficient approach to home heating. And this absolutely does not touch on what the likely efficiency was of the boiler unit producing that heat—an issue greatly offset by the reasonable fuel prices throughout that period. Of course, that is not the case today.
All in all, not a particularly strong endorsement of hydronic heating when compared to the easily adjustable warm air system I found at home.
Jump ahead about 25 years and I found myself living in a Chicago high-rise that also relied upon a hydronic system for both heating and cooling. My fan-coil unit was a much more modern affair, with an effective thermostat that served me well in either winter or summer. And it's obvious, by looking through our boiler and hydronic round-up and Steve Bennett's article on the subject, current hydronic radiant heating systems installed in the floors take this technology to an entirely different level. For the added cost of such a system, the customer can enjoy some notable benefits in efficiency. Indeed, hydronic-based radiant heating provides somewhat of a luxury niche that harkens back to the radiant heating coming up from the floors of the ancient Roman baths. Although the recent trend towards new luxury construction has obviously slowed, it certainly offers our industry members another valuable tool for serving the needs of its customers.