Part of what I intended is they use accurate thermometers. The accuracy is very very high (my cheaper LOL one is +/- 0.02ºC . Many many times better than what is commonly used.) When they say 81 they mean 81 accurately. The typical range is +/- 2º I do not believe this is good enough 81º not 79º as a max. They are using very accurate instruments. Knowing temps are accurate is critical in this kind of a set up. I use an RTD platinum thermometer. I have it re-calibrated every year so I know it is correct. I would not attempt with out KNOWING what the temps actually are and that is expensive. I spend a massive amount on instrumentations for my work and know how poor most cheap thermometers are.

I am sure VPI know the temps accurately and can maintain them. I can't speak to commercial or home HVAC systems I work with lab grade gear and I can assure you that room temps can be controlled accurately. I don't know if they do, but they have good instruments.