My condo building in chicago is a 4 story, 36 unit building. It was built in 2005. Bricks and concrete. The furnaces are electric furnaces (unusual, I know).

Many of the units are way too humid in the winter, causing lots of condensation on the windows that drips down and gets everything wet. I promise the humidifiers built in to the ductwork are completely off.

Have any thoughts about the root cause / how to fix it?

We had used a portable style dehumidifier, but we are now renting the place out and want a more permanent fix.

We got an estimate for a "whole house" dehumidifier, but were told it would be too big to fit in the (not tiny) crawlspace where the furnace is located. The estimate calls for a Honeywell TrueDry 65 to be put in the bedroom, which isn't a great solution (noise). The condo unit is under 1000 square feet, how big should the dehumidifier be?

Another suggestion I got from someone else was to use a "fancy" thermostat that runs the AC unit in the winter as a dehumidifier. Thoughts on this? Danger to the AC unit if the temperatures get to low (snow, ice, etc)? They said I would need to have a low ambient control. Is this a reasonable and safe course of action?

Lots of questions, thanks for any help!