HVAC for an ICF house with SIP roof
Hello All,
I’m in the process of designing a 2,200 sqft ranch with basement in Zone 5 – Putnam County, New York. House will be ICF walls with SIP roof. All interior framing will be steel. I want to use a air-to-water HP for domestic HW and hydronic radiant, but am struggling with the best way to handle the air conditioning during summer months. The designer I’m working with is pushing me towards radiant cooling and using an ERV with HP for dehumidification. I’m leaning towards a ducted system instead of multiple wall units or ceiling cassettes. Any advice on how best to economically achieve AC in addition to the air-to-water for hydronic radiant heating would be greatly appreciated. Thanks
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Doing some similar in Zone 6A. Heating is hydronic heat in floor. Ventilation and air conditioning is a Building Equinox CERV2 with a dehumidifier. Additional cooling is from a Myson fan coil.
Too many systems for me! Also, much better methods of building roofs.
Regarding your question: if budget isn't much of a concern, you'll have more options. Otherwise, an ASHP with wall, floor, or ceiling units, or short run ducts, or any combination of the four, will accomplish heating and cooling in a more cost effective singular system. You'll still need an HRV.
Thank you! I'm all ears and interested to hear more regarding your comment "Also, much better methods of building roofs". Thanks again
Is your ceiling flat, vaulted, or a combination of the two?
I don't think you'll find a lot of love here for either ICF or SIP. Most contributors prefer more conventional construction.
That is where I was headed- but can not make a prescription without a better understanding of the home. With a flat ceiling, of course, the path forward is simple.
To my ear SIP means cathedral ceiling.
The best way to do what you want is to have two heat pumps, one a ducted minisplit and one that is air-to-water.
Where you are is going to be heating dominant, the EPA guide says Putnam county has a HDD/CDD ratio of 2.2. So your heating system is going to need to be bigger than your cooling system. Do a Manual J, and size your ducted minisplit for your cooling needs. Then size your air-to-water to make up the difference between the heating capacity of the minisplit and your heating load.
Be very careful to use the ratings for both heat pumps at your design temperature, they fall off quite a bit as the temperature drops. Putnam county looks to be 6F which is well within range for a heat pump.
I would not use a SIP roof for a new home. Had a repair call years ago (I did not build the house) and the roof had leaked quite substantially. The OSB outer sandwich was basically mush in many areas. There is no repair to this type roof, why risk it? There is also potential air leakage between panels with a headache following.
Doug