If you’ve lived in at least one apartment unit in your life, you’ll know what I’m referring to when I talk about the air handler closet. It’s the one closet in the apartment that has a metal door, instead of wood or any other material. This closet is where the air handler is kept, which is the interior portion of a split air conditioning system. Normally, the closet for the air handler is just big enough to house the handler and possibly the water heater. You could use the space for storage, but I wouldn’t recommend it – here’s why. Last summer, I used the air handler closet to store a few folding chairs and some tarps for outdoor use. My air conditioning system coincidentally started to put out worsening air quality each day since I put those things in the closet, but I never made the connection in my head! Eventually, after several months of a gradual decline in my indoor air quality, the A/C system completely died on me. I had no idea what caused this, until a certified heating and A/C technician came to the apartment on behalf of the property management. The first place he looked was, of course, the air handler closet. When he saw the tarps and chairs blockading the air handler, he couldn’t help but laugh! He turned to me, explaining that this was a huge no-no when tending to the heating and air conditioning system in an apartment. “You’re lucky”, he explained, “this could have caused severe water damage in your apartment!” Apparently the drip pan for the A/C system was also in this closet, and it was full to the brim with condensate from the air conditioning unit. He was right – I definitely was lucky this didn’t get worse!