Climate control is a major issue that needs to be addressed when choosing a hotel.
The first thing you have to check before booking a hotel is whether there is Air-Condition in the room. But even if there is Air-Condition in the room, you are still not in the safe zone.
If the Air-Condition is too old, it may not function properly. It may be noisy or not strong enough. The newer types of Air-Condition nevertheless, with electronic control and high end technology, are ideal.
But (yes there is another but), even if the room has Air-Condition and it is the latest technology, again there is another thing that could go wrong.
Believe it or not, there are hotels which turn off centrally the Air-Condition after midnight, in order to save money. This practice is not only inhumane but deceptive because at the time of booking, when you check for a room and you see the Air-Condition sign, you assume that it will be continuous service and you will be able to control it. You might not be aware that this practice occurs but it does.
Some hotels in Rome for instance, are using this practice which is utterly deceptive.