Topic 'HVAC Makeup Air Units' in forum 'Home Improvement' - dslreports.com

Re: HVAC Makeup Air Units

Sun, 03 Feb 2013 15:07:53 EDT

ArgMeMatey posted :

Need to make a distinction between heat recovery devices and makeup air.

Yes. These contractors did not make that distinction, but it is an important difference, and that's why I am asking the question.

When I had contractors in to bid, they said if I needed makeup air for the three exhaust fans that I was adding, they would put in an HRV or ERV.

I told one guy that our old place had a duct from outside that came in to the furnace return air duct and he said he'd never seen that setup before. Another guy said to just connect the kitchen hood duct and the bath exhaust ducts to the ERV, but it didn't seem like a good idea to be sending steamy, smoky, greasy air through the core. I've been in other houses where they used an ERV for the bathroom exhaust but not the kitchen hood.
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Re: HVAC Makeup Air Units

Sun, 03 Feb 2013 14:41:04 EDT

tschmidt posted : Need to make a distinction between heat recovery devices and makeup air.

Heat recovery units reclaim heat from exhaust air saving energy but do not add air.

Makeup air is exactly that, new air brought into the building - the old air escapes in multiple ways, so by design by accidental.

In my specific case I looked into heat exchangers but given they use electricity (the most expensive source of energy) to save heat, in our case generated by (the least expensive source of energy) wood I decided to forgo.

On the other hand our house is very tight, post and beam with stressed skin wall and roof panels so depressurization is a problem. I installed a fresh air duct near the wood stove to minimize chimney back-draft problems.

/tom

HVAC Makeup Air Units

Sun, 03 Feb 2013 14:21:32 EDT

ArgMeMatey posted : How frequently are makeup air units actually being added in new construction? If they are required, do they also require conditioning, or is conditioning optional?

I'd been told by multiple contractors that if makeup air was necessary they would put in an ERV/HRV, but as pointed out by Lurch77 in another thread, for the most part those are designed to exhaust the same amount of air that they pull in.
»Re: External air supply for an 80% AFUE furnace?

On this season's This Old House, they added what looks like a Comfort-Aire air handler with a hot water coil to provide makeup air for a large kitchen hood. (They're pointing out how small the new condensing boiler is, and then there's this huge air handler that makes up for the old boiler size-wise.)
»www.thisoldhouse.com/toh/tv/vide···,00.html
(Episode 3215, Scene 5, at 8:25)
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