Sizing HVAC System for ICF House
I have an ICF home under construction. The typical HVAC quotes I have received are based on sqft from what I can tell. (24,000BTU)
First time poster, but I’ve been reading up on this tread for my construction project since I started planning this a couple years ago.
This home is super unique. I will upload a few drawings.
Every Manual J test I have seen does not take into account Thermal Mass (Most walls are 10″ concrete with 2.5″ foam on both sides, the East wall and around the stairs is 8″ concrete) or allow me to enter 4″ concrete for the roof.
The main portion of the living space is 820sqft downstairs and has 23′ ceilings and a 5″ slab floor. There is a loft over this floor about 580sqft including the stairs. So I am testing with just 1 floor but at 23′ ceilings. Is that ok ?
My ceilings are 4″ concrete roof deck. They are flat and will have spray foam insulation to the required depth.
There are minimal interiors walls. And there are none that prevent air flow from one side of the home to the other. I also have a HRV Lunos e2 kit.
and the vents are on the East and west wall. Plus 2 ceiling fans.
I have many windows. 450 sqft for the South wall alone. All windows are Low-E. But the East and west only have 66sqft combined and North wall 1 window at 30sqft. I have great shade on the West side of the home with tall 50’+ trees close by
I am in Zone 4A.
I am wanting to do mini-splits and I’m not sure just 1 in the living room will do the whole home or if I should get 2 smaller ones and place the 2nd one in the loft.
My Architect thinks the HVAC design I have is twice what I really need.
Does anyone have experience with an extremely tight envelope and large thermal masses of ICF homes ?
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