Recommendations for heating/ventilation equipment? New construction climate zone 6
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I’m putting together a twinhome project. These are small 900 sq ft units on frost protected slab. R21 walls R49 ceiling minimum with attempts towards air sealing and advanced framing. Running rough numbers I think the heat load will too small for a gas furnace (which is what the use 99.9% of the time here in the midwest), I estimate around one-ton. Setting that aside, what do you think for heating equipment and ventilation? I’m trying to keep these cost-competitive but I do see ERV/HRV’s as added comfort and an amenity. The units vault throughout, but I could drop the ceiling in the hallway/baths to accommodate the heating equipment and duct work.
Any thoughts?
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Replies
That dropped ceiling in the hall is just begging for a ducted minisplit.
And if you're making "attempts towards air sealing" an ERV isn't an amenity, it's a must. Ok fine, you could do just some exhaust fans but air quality won't be that good unless you think about supply air also. The Panasonic Intellibalance does 50-100 cfm, probably just right for this house.
Depending on climate, a kitchen fan alone can easily exceed 1 ton.
The way smaller units are done around me is with a power vented hot water tank with an oversized burner, in an open system with a hydronic air handler like this:
http://www.airmaxtechnologies.com/maxairlv.html
The whole setup is pretty compact, usually fits into a small closer size space. Most power vents run around 80% efficient when used for space heat.
You can also look at a ducted air source heat pump. Your loads are low enough and the layout simple that any of the low static ducted hyper heat units will easily work. Some of them even have connections for fresh air intake so it is pretty simple to connect an HRV/ERV to them.
If you don't want a full HRV/ERV, you can also look at the Panasonic spot ERV, it is about right sized for a small two bedroom place. Not the most efficient and reverts to exhaust only in cold weather but it is pretty cheap and easy to install.