Radiant-floor heating systems are unobtrusive because the plastic tubing that distributes hot water around the house is buried in or under the floor. Homeowners like that. But because there are no air ducts with a radiant-floor system, air conditioning must be added separately.
That’s the situation Lance Peters faces as he plans a new, two-story house in Ottawa (what Peters assumes is the U.S. equivalent of Climate Zone 6 or 7). He’s currently planning to use hydronic in-floor heat on all three levels of the house, plus either a heat-recovery or an energy-recovery ventilator with its own ductwork.
“The house will be superinsulated (~R-40 walls, R-60 attic, R-20-30 below grade) with southern exposure and proper window shading to limit solar radiation,” Peters writes in a Q&A post at GBA. “Finished plans should be around 2,500 square feet. A large portion of the second floor will be open to the first floor (above the living and dining room areas and main staircase), leading me to think ductless minisplits would be a bad idea.”
Peters would like to use the ducts for his heat-recovery ventilator to supply cool air in the summer. “It would be nice to avoid doubling up on the amount of ductwork running through the house,” he says.
Is that plan feasible? That’s the topic for this Q&A Spotlight.
Use an air-source heat pump for both heating and cooling
One of several types of air-source heat pumps would be a good choice for a superinsulated house, GBA senior editor Martin Holladay suggests. There are three basic varieties: a conventional air-source heat pump with ductwork to distribute the conditioned air; a ducted minisplit using a smaller, more localized duct system; or a ductless minisplit.
“Once you’ve installed your air conditioning system, you can use…