400M

With that level of guitar, I would recommend investing a bit more and look into humidifying the room your guitars are in or humidifying your whole house. That way, you can leave your guitar out on a stand or hanging on the wall, and you get the added benefit of making your house much more comfortable. My house is \~1200 sq ft, and [this humidifier](https://www.homedepot.com/p/AIRCARE-VALIANT-Gal-Cool-Mist-Evaporative-Whole-House-Humidifier-for-4-000-sq-ft-Brushed-Nickel-HD1409/204364015) is capable of keeping the whole house at 45% (though I do need to fill it more often in the winter months). You would fill it much less often if you're just keeping a single room humidified. The other thing to look into is a [humidifier that plug into your furnace](https://www.homedepot.com/p/AprilAire-Model-400-m-Water-Saver-17-Gal-for-up-to-5-000-sq-ft-Whole-House-Evaporative-Humidifier-With-Manual-Control-400M/312148211). These are great because, once the initial water line is run and the humidifier is installed, you don't have to worry about refilling. It's literally a set it and forget it solution.

Regardless of where you mount it, the evaporated moisture will have to pass through the return and over the filter. You can't avoid that and its perfectly fine to do. Id recommend an aprilaire 400m. For that model it fills a tray and has an absorbent pad that wicks up the water in the tray. As the water evaporates it will refill the tray. It uses a lot less water than a constant flow model. They tend to work better with heat pumps that have a lower temperature output than furnaces. The water in the tray and on the pad is heated over time and evaporates better than a constant flow model as the water is usually cold.

I have this whole-house unit installed in my forced air furnace: [https://www.aprilaire.com/whole-house-products/humidifier/model-400](https://www.aprilaire.com/whole-house-products/humidifier/model-400) In 2015 it cost me $816.50 to have it installed (I'm in Pennsylvania) - including parts and labor. So maybe estimate $1100 today. We turn it on with a fresh filter, usually in December, and it runs on automatic through the winter. I should change out the filter at least once in the winter but I usually don't. We turn it off in March/April.

Just get an aprilaire 400. They work fine for that size house.

My Aprilaire 400 works just fine with cold water. My windows sweat if it's set too high.

I have Mitsubishi P series as well. I put an AprilAire 400 on my return duct. You can locate it on the front (narrow) side of your return duct. Feed it from the close by supply side. Only use your thermostat for temp sensing not return. This is configurable in function settings. Works great. Steam uses too much electricity IMO.

Used to use those, they sucked. If you dont fill with distilled water they get white powdery shit everywhere, and they have to be refilled often. Whole house is much easier. I change the Aprilaire filter once a year. Its only used in the winter. Never would I want to walk around filling 4-5 humidifiers when theres one that never needs to filled. Plus the Aprilaire bypass humidifier was only like $275. **EDIT** nevermind, OP is talking about something else apparently, he has no central air

If you have central heating and air I HIGHLY recommend looking into a central humidifier especially if you are in a very dry area. Set and forget with auto water feeding and humidity setting with minimal (like 1x a year) maintenance. They are usually not super expensive to install either. I like the Aprilaire units.