RPA Refutes Canadian Radiant Study
A recent Canadian radiant heat study claimed that homeowners with radiant floors do not set their thermostats any lower than homeowners with other types of heat, according to the Canada Mortgage and Housing Corp.
But not so fast, said Lawrence Drake, executive vice president of the Radiant Panel Association. "The study is completely unscientific and very limited," Drake said. "It's a valid issue, but not a valid study, and the matter is a lot more complicated than the study would have you believe."
Last winter, the CMHC sent out a researcher to visit 50 Nova Scotia homes with hydronic radiant heat and 25 comparable homes with other types of heat (mostly forced air, but some hot water baseboard). The visits were conducted during daylight hours on the weekend.
According to the research, the thermostat setting for the 50 homes with radiant heat averaged 68.7 degrees F. Meanwhile, the thermostats for the 25 homes with other heating systems averaged 67.6 degrees F.
"Years ago, we published a consumer brochure that repeated the industry claim that you can set your thermostat lower and reduce your heating costs," said Don Fugler, senior researcher for the CMHC. However, Fugler fielded plenty of calls questioning the validity of the claim. "This sounded like a supposition as opposed to anything that had been tested. We tested the hypothesis, and it didn't hold true."
Drake pointed out that the study does not take into account that there could be a two- to three-degree variation in actual ambient temperature than what the thermostat actually reads. "You can't just look at what the dial says," he said.
Drake added that the study did not look at other important aspects of radiant, such as comfort levels. He also says that force of habit may be the main reason thermostats are stuck at higher settings. "Although homeowners with radiant systems could set their thermostats lower, they often don't since they were uncomfortable at a lower setting with forced air," Drake said. "Now they set it at the same level as before, and they're extremely comfortable."
Fugler defended his work, and said the research is scientifically valid and only sought to address whether thermostats in radiantly heated homes were, indeed, set any lower than homes without radiant infloor heat. He admitted that thermostat error does exist and even told us he had recently discovered that one of his own home's thermostats read two degrees lower.
"With this size of a sample, however, it would be unlikely that there would be any tendency for the thermostats in those 50 radiantly heated home to read higher and the thermostats in the other 25 homes to read lower, or vice versa," Fugler says.
Claims of comfort are worthwhile attributes to research, he said, and added that there is plenty of scientific and anecdotal evidence to back up such assertions. For example, Fugler mentioned a Canadian governmental housing agency active in building homes with radiant heat that found "homeowners love it, and the homes had better resale values on account of the radiant systems."