# Humidifier not maintaining consistent relative humidity



## Dezso3 (Aug 30, 2009)

Just recently I bought a Bionaire digital warm-mist humidifier for $70, thinking that its digital humidistat would maintain a consistent humidity in my room. However, the humidistat is not able to maintain a consistent humidity in my room, because even when the hygrometer in my room read 65% relative humidity, the digital humidistat on the humidifier read 30% RH. The old humidifier that I had was also digital, and it did the same thing. So why are humidistats on digital humidifiers so inaccurate? And what's the point of buying a humidifier with a digital humidistat if it can't even maintain a certain level of humidity?


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## CallMeChaz (Feb 6, 2010)

First, some definitions so we can communicate. If two hygrometers are reading 35% apart, they are not "inconsistant'. One or both of them is "inaccurate". Even inaccurate hygrometers tend to be consistant.

Second, I hate to ask, but how do you know the hygrometer in your room is accurate? Maybe the two on the humidifier were right. (If your room hygrometer is analog, it is more suspect than two digital ones that disagree with it. Accurate analog hygrometers cost about $300. You can get a relatively accurate digital for less than a tenth that.)

Third, it's your humidistat's consistancy you need to be concerned with more than your hygrometer's accuracy. If your humidistat keeps your humidity swings relatively small, you have a good unit.  You simply need to move the humidity adjustment up or down to compensate for any "inaccuracy", ignoring the actual setting.

Keep in mind that your portable unit is spewing out humidity 18" away from the humidistat. It doesn't have a clue what the room's humidity is 10 feet away :whistling2:. Don't be too surprised that even a good quality humidistat has a hard time maintaining a consistant, let alone accurate, room humidity.

If accuracy or consistancy is important to you, read unbiased reviews before you buy. Give more weight to positive reviews than bad reviews--unhappy people tend to review things way more than happy people. I find that you can increase the consistancy of the humidifier output by circulating some air from the opposite end of the room toward the unit. Plus it mixes the moist air with the dry air. I makes a big difference in a basement.


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