At least in the United States, air conditioning / heating tends to be too noisy. Often, I stop to turn it off for the night just to have a quiet sleep. This is a problem both in the middle class hotels and in the cheap hotels. I do not know if 5 star hotels have the same problem because I have never stayed at any of these hotels.
What is the reason behind this common problem? Are customers supposed to tolerate noise or sleep without heating / cooling?