Best small humidifier to use for dry rats?

Now that we’re in an upstairs room of the house, we’re feeling just how dry the bedroom (the rats are in here with us) gets in the winter. Chess has breathing problems regardless of humidity levels— we think the problem may be due to lung nodules like those mentioned by another group member recently— but the dryness can’t be helping. He’s been in rough shape lately.

The girls are also showing signs of dry nasal passages. They may have something similar to whatever Chess has, but less advanced.

We’d like to get a humidifier for them, but a) the room is small, and b) we don’t want to get something that will mess with them. Ultrasonic humidifiers, while affordable and relatively compact in most cases, sound to me like they might cause problems for our beans if the ultrasonic bit falls within their hearing range.

Do you use a humidifier? If so, what’s your model preference? Do you opt for warm, cool, or room temperature vapour? Any experience with the ultrasonic type? Anything we should watch for?

We’re considering getting something like an essential oil diffuser (like a mini-humidifier) and just not putting oils in it, only water. Would that work?

Chess would rather have the window open, but when it’s -27C out, that’s not a sustainable solution. We don’t want to freeze him or the others (or ourselves, for that matter). He goes nuts if it’s too warm; anything over 20C is stressful for him on bad days.

(We may be reaching the stage with him where his quality of life is slipping. It breaks my heart to see him become a little old man at barely a year and a half old.)

I have used on in the past and used a cool mist as it puts moisture into the air without risk.

I believe mine was a Honeywell. It had an insert that prevented mold etc and was replaced every few months.

Thank you for the info. Because of the size of our space and the fact that we’ll only need it for a few months a year, we’re looking at this: https://www.amazon.ca/gp/product/B01I36OHM4/ref=ask_ql_qh_dp_hza

It can be used without oil as just a small-area humidifier. After doing a bit of research, it looks like the ultrasonic frequency used is outside the range of rat hearing (it’s 2.4MHz, versus their range of about 20-90kHz).

We’re looking at ordering it tomorrow so it will be here early next week. Cleo had a little bit of dried blood near her nostrils today (definitely not porphyrin), probably due to the dryness. She doesn’t seem otherwise distressed (usual breathing issues notwithstanding). I’m increasing the amount of moist/wet foods they get in the meantime, along with setting out water to evaporate. They have access to plenty of fresh water and make good use of it; once the extreme cold passes, it should become moister in here again.

I figure if we’re waking up with dry nasal passages, they’re probably feeling it too.

Stay away from warm air vaporizers...your walls will go mouldy. Also, keep in mind that if it's extremely cold outside, you don't want to add too much indoor moisture because again, you will cause wood rot. Your humidity should be at about 30% when it's really cold out. You can add humidity in your room safely but just boiling a kettle or a pot of water. Or put a bowl of water on your heat register or vent.