1 vs 2 Heat Pump Units

CPandMeSeptember 29, 2012

We are building a new home with approximately 5500 conditioned square feet on 2 stories and are looking at different HVAC options including conventional heat pump(s) w/ or w/o outdoor furnace or geothermal heat pump(s). We have received estimates from 4 contractors. Three of the contractors recommend 2 units - one up one down, with sizes varying from 5 tons for both to one 5 ton down and 31/2 ton up. The fourth contractor recommends a single 5 ton, dual stage, variable speed unit (the other contractors did not mention the dual stage or variable speed). The fourth contractor is the only one that did any homework before making his recommendations. He sized out the house (we are done with framing) and performed a load calculation/right J.

I am definitely not an expert (wouldn't even consider myself a novice) on these things. My question: Is it possible to condition this much space with a single unit?

I am not sure what info one might need to respond to my question, but will try to provide any additional info needed.


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For that size home and best overall comfort, two systems would be my choice.

Now one large system might be satisfactory but it would need to have very sophisticated zoning controls along with an experienced dealer to design such a system including the ductwork.

However, you will be better served with two separate systems, properly sized HVAC and ductwork.

And please no low end builder grade junk in a nice new home.

BTW, what is location?


    Bookmark   September 30, 2012 at 1:39AM
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A load calculation absolutely needs to be performed. It seems some of the contractors are sizing merely based off square footage, which is a big mistake.

    Bookmark   September 30, 2012 at 1:25PM
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Thanks for your responses.
We are located in western Virginia.

    Bookmark   September 30, 2012 at 7:36PM
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I would prefer two units. I would want a variable speed blower on both units.

Will you be using propane or NG for heating?

    Bookmark   October 1, 2012 at 5:34PM
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No propane or NG. If we go with electric heat pump, we'll supplement with outdoor wood furnace.

    Bookmark   October 2, 2012 at 9:14PM
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Look into the Carrier Greenspeed system. I"ve heard good things about it.

    Bookmark   October 3, 2012 at 3:37PM
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