I know it’s a funny sounding title but let me explain. What I mean by the condition of air is what temperature and humidity is best for good sleep. If you have the air too dry then you can dry out your sinuses and have problems. If the air is too humid then you run the risk of mildew forming in your house. Also, keeping the ideal temperature for sleep is the most critical part of all. They say online that 68 F is the best temperature for sleep and I can vouch for it. Keep your room cool, sleep well. I don’t like having the air conditioner blowing on me directly when I sleep because it causes problems with my throat. If I have to room too hot then I end up tossing and turning all night in a hot sweat. I’m a hot sleeper in general, so I like having a fan on and and my thermostat set at 68 F for my best sleep. I also like to take a nice warm shower each night to calm down my body and get it ready for sleep, a little meditation helps too. I have a new thermostat now that can control each room separately so I don’t need to heat up or cool down a room when I’m not using it, this saves a fair amount of money each month. It’s worth spending a few extra dollars on a split air conditioning system, and you will end up saving money within a year of purchasing the unit from less power consumption.