The "problems" start, IMO, for those who continue to hold the belief that there is a major difference between between heating and "air conditiong."

Since they both make an inhabited space more comfortable, climate-wise, what is the difference?

Whether or not one is "more necessary" than the other seems to be a matter of personal opinion. You can die from extreme cold as well as from extreme heat.

Do they have AC? yes, and they will tell you they do.

Will you actually receive the service? Aye, there's the rub.

To give the hotel managers the benefit of the doubt, maybe they don't understand the concept of a thermostat. (My mother doesn't, no matter how many times I've tried to explain.)

If the thermostat is set for 78 degrees F (or whatever is felt to be a reasonable compromise between comfort and energy use) there is no need to 'turn off' the AC - it will turn itself off unless room temps rise above this value, no matter what the season of the year.

I have no problem with governments urging citizenry to keep thermostats set relatively high (or, in the case of heating, low) but the idea that the calendar month somehow magically dictates what is appropriate, regardless of current conditions or the location of the room (those under the roof tend to have more variable temperatures than elsewhere) is insane.

A source of information is Fodor's books. I purchased the German 2006 and was delighted to see the extensive details about the hotels they recommend...including a/c, no a/c or on some floors.

Of course, you can always ask when you book online if going through their site.

You just need to ask the specific hotels. In Paris and Venice our 3-star hotels both had air con. They were normal independent local hotels not part of any chain.

We have found lots of hotels in France with ac but they seem to turn them on according to the calendar (May to September in some cases) not the heat...