Sizing minisplits for adequate heating & cooling in a cold-climate Passive House
We are building a 2300 square foot Passive House in the midcoast area of Maine and are having trouble choosing and properly sizing our mini splits for both adequate heating and cooling. We live in an area where of course it gets below zero many times during the winter. So we are limited (I think) to the brand of mini-split we can choose from. (mitsubishi hyper-heat) I have been reading a lot of articles about the installation of oversized mini-split systems that short cycle and end up needing an additional thermostat to correct the problem….we are hoping to avoid oversizing our units, but from the articles I’ve read, it seems to be unavoidable as they all seem to have the same lower threshold. Secondly, there seems to be, not surprisingly, such a disparity between the heating and cooling calculations done by our Passive House consultant and our HVAC tech that we are having difficulties convincing our HVAC tech that the systems we want are sufficient (he wants us to sign a waiver if we proceed with less BTUs and/or smaller units than he is suggesting) – which in turn makes me nervous. My own concerns are more specifically about providing adequate cooling while not oversizing the heating units so that we are functioning within the passive house standards. Ideas, thoughts, suggestions would be greatly appreciated. The house is three levels and will have a ERV system as well.
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