Comfort & Air
Humidity, ventilation and airflow: dehumidifier sizing, ASHRAE 62.2 whole-house fresh-air CFM, air changes per hour, duct CFM and register count at 400 CFM/ton, and psychrometrics — dew point and heat index.
Dehumidifier SizeSize a dehumidifier in pints per day from your room area and dampness level, using labeled reference bands. Free, no signup, formula and example shown.Ventilation CFM (ASHRAE 62.2)Calculate whole-house ventilation airflow with the ASHRAE 62.2 formula from your floor area and bedroom count. Free, no signup, formula and example shown.Air Changes per HourWork out air changes per hour (ACH) from airflow in CFM and room volume in cubic feet. Free, no signup, with the formula and a worked example shown.Duct CFM / RegistersEstimate total supply airflow and how many registers a system needs from its tonnage at 400 CFM per ton. Free, no signup, formula and example shown.Dew PointCalculate the dew point in °F and °C from air temperature and relative humidity with the Magnus formula. Free, no signup, formula and example shown.Heat IndexFind the heat index or feels-like temperature from air temperature and humidity using the NWS Rothfusz formula. Free, no signup, with a worked example.
Every Comfort & Air tool is calculated server-side — visible immediately — with its formula, a worked example and a reference table. Background reading is in the guides.