Return air

[Kirk Middleton]

I've run into a number of instances of no cold air return (ducted) on the top floor of a house (mostly older homes). Is this something that should be called up or is it acceptable? Also is there a sf area of returns per sf of floor area?

[Roy D. Cooke, Sr]

I always Write it up and let the client know ,
No big deal Its been this way for ever and the cold air goes down the stairs .
Could be expensive to fix if you missed it . I say nothing about size of returns ,

[Kirk Middleton]

Roy
I have been noting it and recommending doors be undercut.... just wanted to make sure I wasn't missing something or should be recommending an HVAC review
thank you

[David A. Andersen]

Cooke is in Canada, where you Kirk?

Seeing as HVAC inspection for a home inspector islimited to turning the thing on at the thermostat and seeing if it runs and analysis is not the responsibility of the home inspector, we can safely assume it's not your responsibility to report it. However, when the individual is totally uncomfortable and has adverse conditions in their house you may get blamed. it will cost you to get out of it regardless.

if you care to report it, I can back you up 100% of the time because you cannot do two floors of a building with one HVAC system unless it has a zoning control system installed.

if you're in the lower 48 states, hot air rises and you cannot air condition that air when the return is on the first floor. So the answer is that you cannot properly condition the house without type of the system in every case. Whether they recognize it or not is another situation entirely.

People that have mold have moisture problems. People with screwed up HVAC systems cannot remove the humidity. Humidity causes condensation. Hydrologic cycle?

[Joe Funderburk, CMI]

I refer it out. Also, a 2 story home with just 1 thermostat, I bring that to their attention as an FYI item.

[Robert J. OConnor]

Originally Posted by dandersen

... you cannot do two floors of a building with one HVAC system unless it has a zoning control system installed.

I agree. Two floors require at least two zones to effectively and efficiently heat and cool a home. Heating only is a different story.

And about return sizes just check that it's not very noisy at the return.

[rspermo]

The sizing of the return (particularly when discussing A/C) is related to the supply air. For example, if a 3 ton unit nominally supplies 1200CFM then the return ducts need to bring in 1200CFM. Easy way to size the duct would be to use a "ductalator".

[KEVIN WOOD]

We have allot of homes designed this way. I recommend a return installed along the inside wall to upstairs but this must be done by a certified HVAC technician that understands why and how it should be done. Not so easy to convince them it needs to be done to get the full benefit of their HIGH EFFICIENCY CONDENSING FURNACE.

[Charley L. Bottger]

IMO the # 1 problem with centrally designed air distribution systems is poorly/inadequate/improper/undersized or any other name you can think of return air side of the system. Try blowing air into a beer bottle one can only blow so much in without removing the same amount