Return Air but no supply air

I inspected a condo and the utility room had a return air vent that connected the room to the space outside the utility room. I see this often in bedrooms to provide return air when the door is closed, however those rooms always have a supply air register as well. The condo utility room had no supply air. Is this proper?

I don’t see how it will harm.

To start it is a “Jumper Duct”, not a return. Had to read the OP several times.
It is not there for HVAC return air.

Next question; what is in the utility room?
If you have an appliance that uses indoor air (furnace, dryer, water heater without it’s own combustion air source) the jumper is there to provide this air from the adjacent room. You need to look up what is using air and determine the indoor square footage required to provide that air.

Removing the jumper with free air appliances will cause a carbon dioxide threat.


The condo was all electric.

ALL Electric condo??? Why would you need supply air for HVAC

I suggest you do some research for why is supply air needed for and electric furnace.

The question was why there was a duct connecting the utility room with the hall outside the utility room to share return air when the utility room door was closed but no supply air for the utility room. Nothing was said about an electric furnace needing supply air. I suggest you read the original posts.

This condition could be attempt to provide some minimum air circulation. Undercut door should allow some air in.
In utility rooms with the gas furnace or water heater proper intake air would be required.

Andrzej, this utility room had only an electric dryer and washing machine along with some shelving and an electrical panel. I was just wondering if it should have an AC duct to provide air from the HVAC system since it had a jumper duct. When I see jumper ducts in other rooms they always have an AC duct as well. I’m not sure how the conversation turned into a discussion of combustion air requirements. I think it’s fine, but was just trying to see if someone with HVAC experience would respond. Thanks.

It was not my intention to offend you by adding extra comment about gas fired equipment utility room it is obvious - sorry.
In my opinion electric dryer need to draw the air to function properly. It is possible that why the “return” or air bypass was provided.

No offense taken. Thanks.

I have often seen houses framed one way without knowing what appliances will eventually be installed. Ever see electric and gas supply to a utility room with one or the other not used? Some AHJ’s require things because it is not known what will eventually show up in that room.

This is not an HVAC duct for Heat/Cooling, it is for ventilation, hVac. The dryer requires ventilation for proper operation and to prevent fire just like any combustion appliance. The math is just different.

It hurts nothing to be there. Better safe than sorry.