Exploring alternative radiant heating surfaces

Prior to the introduction of radiant floor heating systems, many people in the world had the opportunity to experience the comfort and health benefits associated with other alternative radiant heating systems. Remember those big cast-iron steam radiators that grandma and grandpa used to have in their house? Well, 60% of their output was in the form of radiant heat, with the balance being in the form of convective energy. And as your childhood memories remind you, the warmth and comfort associated with those radiators was fantastic.

Many of us probably also have a childhood memory that pertains to having gotten burned by those extremely hot radiators. We all make that mistake at least once in our life: “I wonder how hot this is. YEEEOWWW!” Needless to say, it was extremely hot. But this one mistake, stuck forever in my mind, is one that I will never make again. Live and learn.

Another childhood memory of mine also pertains to the heating system in my grandparents’ house. Their old furnace (boiler) was coal-fired. And I remember my grandmother telling me that I should never go downstairs because a fire-breathing dragon lived down there. I just remember hearing a lot of clanking and banging going on when she’d go downstairs to restoke it, and I remember an occasional puff of smoke coming out of the basement. I never pushed it any further than the top of the stairs. I did, however, have an occasion as an adult to eventually find myself back down in that basement. I was actually there doing some service and repair work for the people who owned it, and I discovered that the fire-breathing dragon was actually a rather large coal-powered steam boiler. It had been converted to natural gas by the time I finally met it face to face. Another childhood memory shot down …

But the one early childhood memory that will stick with me for life is the overall warmth and comfort associated with the radiators in their house. It was unlike any other that I had ever experienced. I loved going over there during the cold winter months because it was so exceptionally comfortable and warm. I think we all have early childhood memories that remind us of things related to comfort. The only problem is that we as an industry have never had a true definition of comfort. Comfort is a subjective term. I have worked for attorneys who could not give a true, clear definition of comfort, but understood how to express and attach a monetary value to discomfort.

Each person has his or her own definition of comfort. My personal definition is “not being aware of your surroundings. You are not hot, nor are you cold; the humidity is not too high, nor is it too low. And none of your olfactory sense are being violated.” Simply stated, if all things are good and at equilibrium, you are comfortable. If anyone of these critical elements is out of balance, then you are not comfortable.

Although we can’t see it, the Mean Radiant Temperature (MRT) drives the bus of human comfort. This one factor has more influence over human comfort than all of the other factors combined. In fact, the MRT dictates what most of the other parameters need to be (excluding humidity) in order to deliver good comfort. A higher MRT requires a lower air temperature in order to deliver the same degree of comfort. Maintaining a high MRT with a high air temperature will result in major discomfort for the majority of people who are exposed to it. It is difficult — actually, not feasible — to attempt to manipulate the MRT with a typical forced-air distribution system. It requires such a high air temperature that people are immediately uncomfortable from excess heat. And if you have ever experienced an excessively high MRT, you know what the “mean” in mean radiant temperature really stands for. Just kidding. It actually stands for the average.” With the exception of a Bikram yoga studio, it is extremely critical to control the MRT in order to deliver good comfort. For those of you who understand what a Bikram yoga studio is, there is an excellent marketing opportunity for you to sell radiant floors, walls, ceilings and windows. For those of you unfamiliar with this particular method of yoga, it requires a high mean radiant temperature, which forces the participants to utilize their operative cooling mode. I call it evapo-transpirational cooling. My wife calls it sweating.

This all basically boils down to what we call the operative temperature, which is a combination of the ambient air temperature and the relevant MRT temperature. The final result of all this, along with the control of relative humidity and other critical environmental factors, equates to the ability to deliver comfort. Most all of us are in the “comfort business.” If we cannot deliver good comfort, we will not have very many happy customers, and as a consequence our telephone will stop ringing. That’s never a good scenario for a business person.

Tune in next month as we continue to discover alternatives to radiant floors. In the meantime, if you are not yet a member of the RPA, please consider joining this worthwhile organization. Visit us at www.radiantprofessionalsalliance.org.And happy hydronicing!!

All Mark Eatherton material on this website is protected by Copyright 2013. Any reuse of this material (print or electronic) must first have the expressed written permission of Mark Eatherton and CONTRACTOR Magazine. Please contact via email at: [email protected].