Js Cantrell

Awesome! Thank you Nick L. You're right, the math beyond me, but the calculator is just what I was looking for. But I wouldn't have known how to use it if you hadn't explained that I need to derive dew point and then plug it back in. Perfect! Cheers! My reason for asking is I wanted to know what happens when warm, dry outside air is drawn into a long, narrow, cool basement (20' x 200') at one end with an intake fan while the existing basement air is evacuated with an exhaust fan at the other end. I have humidistats/thermometers throughout, and once the air exchange is complete, I turn off all fans. My goal is to reduce humidity in the basement, but I don't want it too hot down there either, so on those rare summer days here in Tennessee when we get low RH and moderate temp outside, I suck in outside air to help the dehumidifiers keep the basement dry. The basement has concrete floor, ceiling, and walls, so the drawn-in air gets cooled down. The calculator will help me determine when I should and shouldn't ventilate! The rule of thumb I mentioned is ok, but something in me, curiosity I guess, just wanted to know a bit more. Thanks!

thank you ajpoolshark:)

Bueller? Bueller? Anyone?

Hi, I joined the forum to ask a question that I can't find the answer to on the web. I'm looking for a formula to precisely answer the following question: an air mass with 34% Relative Humidity (RH) and 84°F = what RH if that air is cooled to 72°F? For example, in a basement. I know the Rule of Thumb : Relative humidity doubles with each 20 degree (Fahrenheit) decrease, or halves with each 20 degree increase in temperature, but is there an easy formula to answer precisely? Thanks!