When I bought a portable air conditioning system last month to help save money on energy bills, I did not expect the portable air conditioning system to be as noisy as it was! Every time I was running the portable air conditioning system while sleeping, whenever it would turn off or turn on, it would jolt me and wake me up! If the portable air conditioning system was running while I was sleeping, I would zone out on the white noise and drift off to sleep. But then it would shut off and wake me up! The same when it would turn on following going to sleep in quiet sounds. I couldn’t take it anymore and I took it back to the store. I told them it was too darn noisy and that I wanted my money back. It was then the store manager said to me that it shouldn’t have been noisy at all, and that I most likely had a faulty portable air conditioning system unit. He then asked me if I would try another one to see if it did the same thing, and if it did, he said I could return the portable air conditioning system for a full cash refund. I agreed because I wanted to try to save on the use of my central air conditioning system. And would you believe it? The store manager was right! This different portable air conditioning unit was smooth and all. It made a little noise naturally, but no more than my central air conditioning system when it turns on. I never ended up returning it.