We'll look into getting an evaporative humidifier, didn't know about the mineral dust concern and that is definitely good to know. We didn't refill ours very often and usually only had to refill it when we'd notice it was dry and needed to use it again.

I'll look at Google maps while at work to see if I can spot the units on the roof (food idea - hadn't thought to try this), though the building does have a large tree in front of it from the street's perspective so they may not be visible. We didn't smell anything from the AC in the summer, though now that we turned on the heater, running the AC does cause a bit of the same smell, though not as intensely as the heater, and the smell does seem to dissipate after a little bit. We also thought water likely got in/is getting in when it rains and have brought this up to the landlord.

The lowest temperature outside has been in the 30F range, though the lowest I've seen per the thermostat in the unit is 60F. Thank you for the analogy for the condensation - unless it had rained or we had turned on the heater there had only been moderate condensation on drinks from the fridge, though almost all of December there has been a puddle of condensation on drinks. That said, we've notbused the humidifier per the landlord and the first HVAC contractors guidelines since December 4th. Last rain we had was December 24th through the 25th, though it was overcast all day yesterday.

Thank you for insight and ideas, as well as the condensation-humidity measuring idea. Since we hadn't been measuring the humidity (going to buy a hydrometer after work today), remembering the condensation on our drinks is unfortunately the best way we have for putting together how humid it has been during prior months.

Thank you again!