air conditioning use regulated?

There are regulations, not only for A/C, but also for heating in the winter. Dates vary throughout the country. Maybe on of our Italian corespondents can chime in. The info is out there, I've seen it, but it will be in Italian. If you know how to search only Italian websites, you can probably find it.

I don't know about A/C regulation, sorry.

I can offer a suggestion on the noise issue - download a white noise app, or white noise playlist on a music service/album to your phone or ipad. Plug in your device overnight and play the white noise at a volume sufficient to cover much of the street noise. It works similar to running a fan or A/C and is more environmentally friendly if you don't actually want the A/C, just the noise. It also allows sleep with windows open which can be nice, depending on temperature and breezes.

Test the white noise ahead of time - some are better than others, some are kind of quiet, some are loud and annoying with crickets to distract you. Or maybe you like the cricket ones, it's all about your personal preference and comfort!

A roundabout way of an answer here

https://www.army.mil/article/205653/questions_about_ac_heat_up

Joe--are the regulations the same for rest of Italy as for U,S. Army? That part wasn't totally clear to me. What you linked suggests that a/c can be used after May 15 and 3 consecutive days above 80 degrees. That certainly is something I can live with. I also thought it was interesting that a/c can never be below 74 degrees. The US could learn from this--I find I have to often take a sweater to restaurants and office buildings which is an absolutely waste of energy.

And Mira, your idea of white noise from my cell phone is an excellent one. It will of course will not help with real heat but maybe will allow me to comfortably keep the window open. In any case, I do sleep with a fan on at home for white noise so a substitute might make my brain thing it is night time!

There are no hour rules.

However, you may find rooms where the A.C. doesn't work when the room keycard is not in the slot -- so you can have it on while you are in the room but not chilling empty rooms while you are out.

you may find rooms where the A.C. doesn't work when the room keycard is not in the slot

Easy solution, those "slots" (which turn all the electricity off in the room, including lights, to save energy) are simple, they don't read the card, they just need something thick enough in them. Just put 2 or 3 business cards in them when you leave the room. And hope the maid does not remove them.

I have stayed in hotel rooms in Europe where key is needed to turn on electricity. I have found it only mildly annoying (harder to insert card in slot in dark than to flip on light switch).

I was in Naples and amalfi coast a few years ago in July and a/c in hotel rooms was not an issue. The question is whether it will be a issue in more of a shoulder season of late May.

No issue. Assuming you need AC in May (some years May is very cool and in fact next week they forecast snow at just above sea level) you just turn it on.
There are no rules related to the time of the year when you can turn it on (those rules exist for heating only).
There is a law promulgated in 2013 which prohibits keeping temperature below 24 degrees Celsius (75F) but the law applies only to commercial and office environment (basically at work) not private dwellings. The law was promulgated because of some violent disputes between coworkers on what temperature to keep the office, some didn’t appreciate the freezing cold in July and Italians get passionate during debates, including in Parliament

The key card to insert is not an issue either. I use any card I have in my wallet (AAA, AARP, Airline, Costco, Safeway, CVS) and keep the electricity on while I’m away.

All very interesting but sounds like a/c will not be an issue. People here complain about air conditioning but I think it is mostly centralized so no way to actually fight about it.

As I said, I think 74 would be a good temperature indoors.

For the past few years I have been traveling in Italy in May. Hotel A/C is hit or miss. In some areas there are regulations as to when a hotel can start to use a/c and in others it is up to the hotel.

I am currently traveling in Sicily and Southern Italy. No A/C in Sicily or Apuglia but it is on in Sorrento--where it is in the 50's and not really needed.

Last couple of years in Florence, Lucca, Orvieto in May--no a/c.

I have started to pack one of these fans:

EasyAcc USB Battery Fan

Fits in the palm of your hand but has tremendous power. It won't cool down a room but will cool the area around your head so you can sleep. Three speeds and the top speed will have you freezing. I've used it every night and it helped even when the room was around 78 degrees.

Frank,
A/c sounds more random than I thought and the fan is an interesting back up idea. But it looks like it goes around your neck. How did you use it while sleeping?

When you find a hotel that you’re interested in booking...just ask them if they have a/c, will it be available to you on your dates, is it controlled in your room, can you use it any time of the day or night.

And even then (from personal experience) we arrived into our RS pick Paris hotel with all of the above questions answered and lo and behold...AC was unavailable in the whole hotel because it was being worked on the entire time we were there. It was hot and miserable and super loud st night with the windows opened. And we splurged on that hotel because it had AC.

All a part of travel I guess. We had a ferry strike last year in Greece on the one day we had planned to take the ferry....

We recently were in Rome - sweating at night. Front desk said the AC couldn't be turned on. On day 5 of 7, we returned to a lovely cool room. I guess we hit the magic date.

Beth....look at all the photos. When the lanyard isn't attached, it lays flat the the fan part can be raised and lowered.

We just returned from northern Italy. We were in Venice for the nights of April 17, 18, 19. For the first two days, the heat seemed to be on. On the last night, the air conditioning was on. Our room thermostat seemed useless. Venice was quite warm that week, mid 70's. When we left the window open, the bugs came in- we were close to the canal. The hotel claimed they had to adhere to regulation dates for the heat/Av system. [One week later, after we left, I noticed that the Venice weather was cool and rainy.]

Regarding flying in/out Milan: I just posted this on another topic: If you're using the train to Malpensa, be aware that trains can be canceled at the last minute [they run every 30 minutes]. Add an extra hour for getting to the airport, just in case. [The train trip is 51 minutes.]
Safe travels.