The Need for Supplemental Heat with Radiant Floor Heating
Thank you in advance for your time and consideration.
We are building a custom home in climate zone 7a. The home is 3000 sq feet of conditioned space with lots of glass (triple pane tilt and turn), most of it southwest facing. It’s 2×6 construction with 1 to 2 inches of continuing insulation on the outside walls (depending on exterior material). The roof is a non vented assembly that will be approximately R35.
According to the Manual J Heat Load calculations (done by a professional engineer) the total load for our house is approx. 85,000 Btu. We are going with slab on grade with a hydronic system embedded in the slab.
The company that did the loop layouts (and also a heat load calculation which came up with the same numbers) reports that “some rooms may require supplemental heat supply to meet the design load”.
Has anyone ever heard of this situation? Why wouldn’t the radiant heat be able to meet heating demands?
Thank you, everyone here has been greatly helpful.
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