What would you say about this?

Hey guys - take a look. This is an airhandler in an apartment. It is mounted with no bottom for the unit to sit on, so the return air is sucked in from around the whole closet as well as the return air duct. What would you recommend?


That it will not function as intended.

Return air can not be taken from the same room as the furnace. If this furnace were to burn carbon monoxide, it could get sucked right into the return and sent into the living area. Not a good situation. Return air must come from adjoining rooms.

It’s not a furnace.

I see free air reutrns all the time.

Tell us more.

It’s an air handler for an apartment AC/Heat. I guess the main concern is that the unit would not function as efficiently as it should. It’s a 20 year-old Carrier unit.

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I personally haven’t seen this type of set up and would like to know more about system.

Is this an air handler for a heat pump?

As long as this unit is not drawing a return from a non-conditioned space there is not much you can state about the system other than very poor design. Does this unit have electric heat strips???

It’s leaking water!

As Charlie posted, it must be sealed from unconditioned spaces. These new pic’s show unfinished walls below. Likely, there is leakage. Radon, Mold issues associated here as it will pump it throughout the house.

I see that type of system and set up all the time down here. Nohting wrong with it as long as the return air grate is big enough. “I guess the main concern is that the unit would not function as efficiently as it should. It’s a 20 year-old Carrier unit.uess the main concern is that the unit would not function as efficiently as it should. It’s a 20 year-old Carrier unit.”

There is no way this unit will be efficient at this age. This unit is almost entering its third life. As for the unit leaking, I can almost guarantee you that the drain line has backed up at one time or another.

The return should have a sealed plenum even if it is a free air set-up such as this one. Their should not be any open space on the sides of the unit shown above. What is a plenum you say? Lets look at the code:

**International Mechanical Code 602.1 **A plenum is an enclosed portion of the building structure that is designed to allow air movement, and thereby serve as part of an air distribution system. Supply, return, exhaust, relief and ventilation air plenums shall be limited to uninhabited crawl spaces, areas above a ceiling or below the floor, attic spaces and mechanical equipment rooms.

Note: This system must also be installed in accordance to your state and county building codes.

I can’t believe the installations I’ve seen from some of you guys.

Besides the unit age, and the obvious lack of maintenance, efficiency isn’t MY biggest concern. Breeding molds, fungus’, etc. is probably my biggest worry.
Charley, correct me if I’m wrong, but can you tell if this “free return” design AHU is connected to any S/A duct (ie:plenum, trunk, branchs,etc.) or is it just free blow into a single space area.
Mechanically, operation is inefficient, probably no real de-humidification during A/C operation and I’d guess that the blower wheel is cavetating, which means no real effective airflow, appears no airfilration, etc., etc…
No question in my mind, you would be obligated to write up, big time, in your report. I know I would.


No Greg nothing surprises me anymore. Can not tell from the pic’s really what is going on other than just a mess.

Andrew, tell them to hire a different company to fix it than what installed it.