Hello everyone, I was hoping for some advice on the size of electric boiler that I am currently arguing over with my plumber.
I am building my house in Kenora, ON which is zone 7A. Its a two story with a footprint of 768sq’. The second floor is open to below in about 1/3 of the footprint. It is a heated slab on grade with R15 under the slab except under the footing (which our engineer adamantly wouldn’t approve and is a whole other topic?)
The walls are R22 + two staggered layers of 1.5″ xps. The attic will be about 2′ of blowin-in celulose for at least R70 ish. I taped the osb and final layer of foam with Siga Wigluv for our air and wrb. I am hoping to achieve 1.0 ach. The windows and doors are fiberglass frame triple panes from Duxton Windows. About 35% of the south wall is glazing with low solar gain, the other walls have minimal glazing in comparison.
We are going with all electrical mechanicals (except the wood stove) as we will put at least 6kW, for now, of PV on the roof.
Our plumber is telling us that he wants to install a 20kW boiler which puts out 68,243 BTU’s. He said he can also disconnect half of the elements so it will technically be downsized. I am trying to tell him a 10 – 12kW boiler should be more appropriate for this kind of a build based on my research.
Any thoughts or opinions? Thanks
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