When you buy something like a portable space heater or a portable air conditioning system, the last thing you expect is for them to be noisy. Well, this was unfortunately the case with both the portable air conditioning system and portable space heater I bought for my home. I found myself not being able to use them at night while I was trying to sleep because they were way too noisy when they would turn on and off. So I could only use them in the day time hours to reduce the use of my central heating and air conditioning system unit. In the day and evening while I am awake and at home, I will turn off the thermostat completely and have just the portable space heater or portable air conditioning system running, depending on the time of year it is of course. My original plan though was to run the portable space heater and the portable air conditioning system at night while I was sleeping to cut back on energy use of the central heating and air conditioning system unit. I am not sure if it is the brand of portable HVAC equipment I bought that makes the difference with the noise level of these things or not, but it is something I may look into at some point when I have some time to read more information about heating and air conditioning products that are portable online. The answer has got to be out there somewhere! Until then, I will keep things as they are.