Sorry to hear about this. I have volunteered in a local orchestra classroom giving lectures on violin making and instrument care. I have had this same discussion with the orchestra teacher. In her situation, the classroom was constantly too dry - so it was the opposite problem but still related to what you are experiencing. I don't know the financial situation of your school district (most seem to be barely scraping by nowadays) but there are three things to consider - the drainage as you mention, the noise and any additional heat generated from the unit. In the classroom I volunteered in, the district chose to put in an undersized single room humidifier and the poor teacher ran into the three issues that I just mentioned except that instead of drainage, she had to fill the tanks all the time. It just wasn't and still isn't an ideal situation but that's the way school budgets often go. In your case, hopefully they look at more options than a windows mounted air conditioner from Home Depot and call it good. If at all possible, try to get a professional heating and cooling consultant to evaluate the room. If you are in a larger school district, they might even have their own HVAC person who could review the situation. I say this because there could be other factors at play with the facility that might be causing some of the humidity problems. The real question will be whether or not it is still humid in the winter time as well. While these aren't specific answers to your questions, I hope some of this helps!