I'm trying to picture in my mind just what kind of setup you're talking about here. I take it you don't have a ducted return and the room the water heater is in is actually the return air plenum. Am I correct?

Please excuse my ignorance but after 35 yrs. of marriage, I am now a single mom trying not to burden friends with my concerns. The best way I can explain it is the water heater is sitting inside a small closet and on one side of that closet is a return air vent. If you look up inside the closet, just above the water heater is a hollow metal box extending up to the ceiling. Where the metal box enters the ceiling is caulked but there is no form of sealant around the door. When the AC comes on you can feel air sucking in around the door. In answer to your question, yes, I would say the room the water heater is in is the return air plenum.

is this WH gas or electric? if it is gas, you should shut the gas off NOW and have someone come fix this issue. a gas WH puts out enough CO to kill you in no time, and this is being distributed thru your house via the AC.

if it is electric, then there is nothing wrong with it being in the utility closet, but the return should be sealed and ducted to a wall, not just open to the closet.

The water heater is electric. The return is not sealed. My concern is that this is causing my AC to run more in turn driving my elctric bill up.

if the WH is putting off heat, then yes it is increasing the temps, but modern electric heaters have almost no standby loss.

i would be more concerned with are your filters and both coils clean and not restricted, than with the minute heat your WH is producing.

in my last post i said it should be sealed and ducted, but i meant to explain further. this way of doing it is not uncommon in my area in older homes. we do not have cold winters, so it really does not matter THAT much. but during winter you can feel the cold falling down from the attic and into the utility closets. the return itself should be sealed to the ceiling around it to prevent this, but it does not necessarily have to be ducted on down and a grill i8nstalled int eh wall.

the only way to tell if it needs to be changed is to have a pro come look at it and see if there is a reason the unit is not operating to spec., be it the duct or another problem.

as to the WH working harder, not really. IF it is fairly new then it is well insulated. put your hand ont eh WH and see if it is hot to the touch. the only place you should feel heat is the area around the outlet pipe and maybe the covers for the heater elements on teh side of the tank. if the tank is cool to the touch, then it is well insulated the air is not affecting it.

you can have your apartment manager turn down the WH temp to less than 120 to save some electricity. WH waste more than you think. heck mine uses more than either of my HVAC systems!

So let me see if I understand this correctly, the return is not ducted is that right? Its pulling from the room its installed in basically? Is this A/C part of a warm air system?

Thank you, everyone, for your help. I am sorry for all the confusion. Your information was most helpful. Thanks again for your time.