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Community and Q&A

Struggling with HVAC decision

John Ball | Posted in Mechanicals on

We are building a 2000 sq ft one story home on a raised slab and are struggling with how to heat and cool it. We live in Eastern Canada and see temperatures as low as -35F to as high as +35F. As we are on the ocean air conditioning is only critical about 12 nights a year.

We are back and forth between a central HVAC heat pump and in slab electric with ducted mini splits.
Finding room for the duct work in the conditioned space is the main problem with the central system as well as a concern for cold floors. We will install at least 2″ of ridged insulation under slab.

Our plan would be to use the mini split when it was efficient and the in floor in colder weather, for backup, and during the winter months when we are away.

The price for equipment and to install the two systems would be similar.

What would the best solution be?

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  1. User avatar GBA Editor
    Martin Holladay | | #1

    Either approach will work, as long as your ducted air-source heat pump is a true cold-climate model that can handle low outdoor temperatures.

    A couple of comments:
    1. Are your sure that your outdoor temperatures never rise above 35 degrees F during the summer?

    2. If you are worried about cold slabs, I strongly urge you to switch from 2 inches of rigid foam under your slab to 4 inches.

  2. John Ball | | #2

    I guess I won't need air conditioning after all ;.) I forgot to convert from Celsius. I like the idea of 4" of foam.

  3. John Ball | | #3

    Sorry, correction to my original post, the temperature range should have read from the 90's to -30F. I forgot to convert from Celsius

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