I cannot emphasize enough the issue people are dancing around here: HUMIDITY CONTROL. That’s what they mean when they suggest an A/C unit. The three keys to productive TR sessions (only one of which is adequately addressed on TR podcasts) are TEMPERATURE (63-65 Fahrenheit), AIR MOVEMENT (two Laskos and big Tornado in my face), and HUMIDITY (LOW). Humidity, for the uninformed, is not described using “relative humidity” which is a sorry, not-helpful metric. Humidity is best described by DEW POINT. But an A/C unit lowers dew point in a room if you prep the room for the workout–NOT by just turning it on at the start. I have a temperature/dew point sensor in my pain cave, and use a Mitsubishi mini-split (high-volume a/c unit) with remote control. Three fans. Get the room down below 65 degrees to start, giving the mini-split a chance to lower the dew point. Then I go. I don’t ever drip sweat–ever. I sweat a bit, but I cannot recall a drop of sweat coming off me during a session (I’m not a heavy sweater anyway) as I wear a sweat band and I do sweat a bit into my shorts and shirt and socks. But no dripping or puddling or anything like that. My nose runs more than I sweat. Standard warning applies: N = 1.
PS: I have a fourth requirement for anyone who cares: AIR FILTRATION. I get pollen issues in the spring–tree pollen. Thus, I run (always) a high-volume HEPA air filter to remove all the particulates from the air prior to a session. I like my pain cave air clean, cool, dry, and fast.