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HVAC design

prikrish | Posted in General Questions on

We are building a new 2900 sq feet home in California.
The contractor is proposing a HVAC design where

1. 4 ton Heat pump with single air handler for main open floor plan.
2. a 3 ton ducted mini split with 2 indoor air handlers – for heating and cooling the bedrooms. 2 air handlers since the bedrooms are located in 2 sides of the house

He proposed this design for ease of install and better flexibility. This comes with increased cost due to 2 external units

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  1. paul_wiedefeld | | #1

    Seems extremely oversized - is this house all glass? There should be a manual J.

    You might be able to use two small ducted units instead of 1 larger one connected to the bedrooms. Depends on the layout if it'll be easier or not.

  2. Expert Member
    ARMANDO COBO | | #2

    There are many variables in Manuals J, S and D (as far as code is concerned, but add Manual T) to make a decision on equipment size, and you only provide the square footage. We don't know about your wall and roof assemblies, insualtion, fenestration, home air-tightnes, stories, equipment loads, SEER, EER, system types, etc, etc.
    Are your goals to get the best or the cheapest? I would be skeptical of any HVAC guy telling what I need without performing ALL FOUR MANUALS WITH ALL THE CORRECT INFORMATION.
    For reference, if I were designing a 2900 sf Zero Energy Ready House, I would use 2 tons.

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