Even though we have central heat and air, I have small window units in the bedrooms so we don't have to cool the whole house down to 68 while sleeping. I sleep in daytime so the fan noise blocks outside racket. When it's really cold out and I don't want to circulate cold air I have a small Pelonis heater sitting on my headboard that has a fan only setting...it makes similar noise to the window AC so it helps me sleep too. Normally I don't hear it thunder with the fan and wearing ear plugs.