Is hydronic radiant heat appropriate in a super insulated home?
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循环板热适合在一个超级隔热的家里吗?
I'm designing our new home in Anchorage, Alaska (building zone 7) to be insulated to R-40 or better ICF walls and an appropriate level of insulation in the roof and slab. I'm taking inspiration from Passive House but not pursuing the official certification. We've already decided on finished concrete floors throughout the home for durability and thermal mass. We are planning to utilize a Sanden air-to-water heat pump for domestic hot water and hydronic heat. I'm inclined to have the hydronic heat installed in the floor but I've heard that it's not necessary and will "overheat the house". One local supplier recommends the Minotair HRV with integrated hydronic heat loop, essentially an improved forced air heating system. My concern is that the slab will be uncomfortable to bare feet (all Alaskans take off their shoes in the home, even at parties) and I would regret not heating the floors. How did you execute in floor heat on the Kenogami house and keep it from overheating?
PS- I don't expect toasty warm floors, just not chilly floors. Thank you for your time!
I would personally not consider building a house on a polished slab on grade in a cold climate without heated floors.Heat moves from warm to cold, your body is 37C, and concrete is highly conductive. all those variables mean your floor will suck the heat right from your feet. The sensation is less pronounced with less conductive flooring materials such as wood, but concrete will always feel colder. It is well explained here –
How to design a home for thermal comfort
And I tell you the above from a personal experience with our last demo house which wasthe first LEED V4 in Canadaand it also metPassive House performance requirementseven though it we didn’t seek certification. We used the house as a teaching venue and one day when I had a class and the floor heat was not activated, but the air temperature was warm. People were asking if they could put their shoes on since their feet were cold, despite 8 inches of insulation below and even a 3/8” surface covering of cork.
我知道板式被动房通常不包括地暖,但你不会看到我建了这样的房子。至少你可以考虑让它“容光焕发”,并安装一些pex管,以备将来使用。循环加热的问题和它超过温度的原因是因为水中有太多的潜热,当它关闭时仍然会继续加热混凝土一段时间。
As an alternative I would suggest you look at aLegalett slab on grade with air heated floors. There is not as much heat in air so it doesn’t over shoot as much, and the entire system is embedded in the floor so there would be no ‘boiler room effect’ of overheating at the manifold in your mechanical room.
Concrete is highly conductive, and even in a home kept at a typical room temperature it will still suck the heat right from your feet.