I have manual control for my whole house humidifier. I've been noticing water on the windows in the morning. When I look at the humidistat it is set for 32% (doesn't say RH but thats what I assume). I got another Aprilaire humistat that just measures RH and put it on top of my existing control. Where the existing control indicates about 32%(5% hysterisis) the standalone unit indicates 44%RH. How do I know which is correct and what do I do if my existing manual control is wrong? IS there a way to clean or calibrate it?
Thank you for your email regarding your Aprilaire humidistat. If you turn the dial from left to right you should hear two clicks. The actual humidity in your home will be the area between the two clicks. For example, if the humidistat clicks at 30% and 36% your actual humidity would be 33%. There is not a way to calibrate the humidistat. It is unclear from your email if the original humidistat is an Aprilaire humidistat, so it is difficult to say if it is out of spec. The accuracy of our Aprilaire manual humidistats are +/- 5%
The moisture on your windows is due to the surface temperature of your windows reaching dew point. This occurs when there is more humidity in the home than what the home can hold based on the current outdoor temperature. As the temperature outside drops you want less humidity in your home. For example when the outdoor temperature is 20F or above we recommend 35% humidity at a room temperature of 70F. If the outdoor temperature drops to 0F you'll want 25%.
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