Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: How loud is this unit?
Document: I have only had this item a month, but if it holds up, it will have been a great puchase. I live in a 925 sq. ft. apt. This unit, running on low, keeps it easily humidified. I have never needed the high fan setting, which is quite loud. The low setting is audible, but not a problem. The unit holds 2 tankfulls of water, one in the base. Each tankful lasts ablut 6 1/2 to 7 hrs, on low.
Been using for a couple months, works well, my favorite feature is the digital humidity readout. Is accurate and on quite is not too loud.
I've had many humidifiers and this is the best one I've had. Humidifies rapidly and quiet on the first 2 settings. Even the high setting isn't too loud considering the output.
Recently bought it at a local retail store, and I have had no problems so far. It raises the humidity in my bedroom (221sq. ft.) rather quickly on the highest fan setting. The highest speed is loud, but I use it when I get home for a short time and then lower it.
I have had this humidifier now for 2 years and it is keeping our living area (approx 1200 sq ft) plenty comfortable. I am having no issues with leakage or spillage and it is very quite in the low mode. It does get a little loud in high mode but low mode is all that we have needed anyway.
Nevertheless, it is valuable as a way to set the unit, but you should have a seperate gage, to read the true humidity. They cost around $10.00.
Does a good job for stand alone unit just a little noisey like a bathroom exhaust fan running all not but the moist air is worth it!
I really like the ability to set a desired humidity level (for me, usually 45 or 50% RH). Once that is done (with a simple push of a button), the unit will automatically power itself on or off as needed.
Seems to be doing a good job, only used it for 2 weeks. Runs quite on low speed, my preferred setting. Easy removable fill tank, and easy to refill and reattach to unit. Would recommend.
Pros-for the first few hours, it will boost up the humidity. With a low fan speed, it is pretty quiet. It's easy to move around and the detachable tank is wonderful. The filter is easy to replace.Cons- after a few weeks of working perfectly, it would only work a few hours after turning the system on. Anything above a low fan speed will make the machine vibrate and is very loud. The case is built horribly and the top doesn't line up with the bottom.
Answer: On the high setting it is really very loud. The volume drops considerably once you switch to the lower two settings. It is not really noticeable.