Open return in basement

Would you call this out as an open return?
Is there a code reference for this?
I checked the Ohio Residential Code, and couldn’t find one.


open return.jpg


Looks like a planned R/A plenum opening. Is the basm’t area wide open and unfinished and/or does it have any S/A reg’s. off the S/A ductwork.
In the old days of my HVAC days we sometimes added a R/A and 1-2 S/A openings to unfinished Basm’t storage type areas to temper the area and reduce the R.H. to a point that contents and framing and equipment would’nt freeze or sweat(condensation).
Any of the above would be moot if any of the area has any earth floor or open crawl space area. Might want to ask a few questions or look at the area again to see if you pick up any other ideas as to a plan of design,

Good Luck


Its on the unfinished side of the basement, along with the gas hot water tank, gas dryer, and a solid door seperating it from the finished side. I told them about combustion air requirements, but I also called out the return air.

open return 2.jpg

Don’t know if its a code violation, but I think it is. I always call it out as being a safety concern though due to the possibility of effecting the natural drafting of the furnace and hot water tank venting, which can cause backdrafting of CO/fumes into living spaces. Recommend relocating to another room or area and blocking the offending vent off.

You can not service two floors with the same unit unless there is a return and supply to all floors.

The extent of the efficiency of the installation will require a zoning system to control air flow.

You can not heat and cool with the same duct system without a controller.

I see all to many basement finishing jobs that just cut into the supply duct. Won’t work guys! The heat/cool load in a basement is no where close to the first floor! At least they are pulling air that needs to be treated from the basement.

The major concern is that the return air duct is within 10 feet of the furnace.
That is a NO, NO! You will pull combustion gasses into the return and pollute the house.

Hi David where you been hiding.

I totally agree with David no return even in the same room as the hot water heater That is worst than a return in the kitchen bacon smell through out the home or in a bathroom with you know what through out the home:roll:


Basically, it sounds like you are describing an enclosed Mech.Rm. area in the Basement.
If that’s the case, then my scenario above would be wrong and I think you did the proper thing commenting on the design/installation, especially on the combustion air and backdrafting concerns.

Charlie, Miss me? :slight_smile:
I’ve been working my a$$ off! Things finally kicked in gear around here and I’ve been working 18 hours a day to keep up. My inspection got postponed this morning (thank God!). I was thinking of a way to postpone it myself when I received a voice message that the client got sick last night!

Yeah I missed you:(

Same here things went crazy impossible for an old man to keep up.

Yup no good