Personally, I started off wanting to disagree with your statement. But I had to do some research to make sure myself.
I know this is going to be a long post, but its important that we don't just make blanket statements.
First, a word on the wax melting. If your wax is melting you must be using some pretty dang hot water (or just some old or bad wax). When I talk about hot water I'm not talking about 211 degree water (just below boiling point) but just water that is hot to the touch.
What can happen with using hot water is any grease or oils that may be on the floor can soften and be spread while your moping (since oil and water don't mix well). But Hot water will dry much faster during the times when the hall or area will need to be used soon.
There are cases for both hot and cold water uses. For example I have always heard hot water enhances (speeds up) chemical reactivity in most cases which means using less chemicals to get the job done and shorter time cleaning since the cleaning chemical is reacting better (or doing the job faster because its excited due to the heat). Thats why it was always believed that hot water was better.
But with todays society going green, new chemicals are being created to use cool water as energy savers (again not having to heat the water up).
In other cases cold water is better for cleaning oils, greases etc.... With the added bonus of not having to pay to heat the water.
There is a great article, (well debate) or discussion here:
http://www.ogs.state.ny.us/bldgadmin/envir...terCleaning.rtfIt's a little long but there are a lot of supporting arguements for cold water use.
And here is a link as to why hot water is better for cleaning:
http://www.newton.dep.anl.gov/askasci/gen01/gen01759.htmBasicly it states that hot water has increased dissolving abilities - (due to entropy) even without soap, small amounts of some greases will dissolve in water.
In hot water, the amount that will dissolve can be ten times higher.
* melting - some greases are low-melting waxes, and being melted makes it easier for the soapy water to penetrate, detach, and surround them. Even things that are not quite melted at least get softer.
So it should definitly not be a cold water only when cleaning the floor issue.
And really, if you find that your wax is melting, something else is wrong with that situation. There must be another problem.
For the radiator situation: any water left on a waxed floor surface will disolve the wax. There are many situations when we had leaks, toilet, roof, pipe etc.... where water had ruined the wax and it had all been cold.
Again sorry for being so long winded.