Many have commented about how the RH drops when there wino cooling unit turns on. While part of this may be due to the cooler air I believe there is another reason.
I have a Newair CC100. It had not been plugged in as I keep it in my basement. It was reading 65% up top and 66-67% on the bottom. I plugged the unit in yesterday as temps in the basement was getting up to 68. I plugged in and set to 70. Now the CC models from Newair, the circulation fan runs constantly at a low speed. Within a couple minutes my hygrometers both dropped a point. The cooling unit itself was not on as it was below the set point. I believe that the moving air has an affect on the RH reading of hygrometers.
Most digital hygrometers work by having a material that absorbs some moisture and as current is passed through it changes the amount of voltage based on the moisture content therefore changing the RH reading. I believe the moving air has an evaporative effect on that material reducing the moisture content and lowering the RH reading. The moisture content of the air itself hasn't changed though.
This morning the top hygrometer that by the way its mounted would probably see the most air movement was down a total of 2 points from where it was before. So depending on the amount of airflow and the orientation of the hygrometer I think a 1-2% drop just from having the fan moving air is typical. Anything more than that if the cooling unit was on could be attributed to that. I may have to test that and see if there is an additional drop when the cooling unit is on.
I have a Newair CC100. It had not been plugged in as I keep it in my basement. It was reading 65% up top and 66-67% on the bottom. I plugged the unit in yesterday as temps in the basement was getting up to 68. I plugged in and set to 70. Now the CC models from Newair, the circulation fan runs constantly at a low speed. Within a couple minutes my hygrometers both dropped a point. The cooling unit itself was not on as it was below the set point. I believe that the moving air has an affect on the RH reading of hygrometers.
Most digital hygrometers work by having a material that absorbs some moisture and as current is passed through it changes the amount of voltage based on the moisture content therefore changing the RH reading. I believe the moving air has an evaporative effect on that material reducing the moisture content and lowering the RH reading. The moisture content of the air itself hasn't changed though.
This morning the top hygrometer that by the way its mounted would probably see the most air movement was down a total of 2 points from where it was before. So depending on the amount of airflow and the orientation of the hygrometer I think a 1-2% drop just from having the fan moving air is typical. Anything more than that if the cooling unit was on could be attributed to that. I may have to test that and see if there is an additional drop when the cooling unit is on.