It's the flooding problem most of all. I'm in one of the few Manhattan co-ops that still allows washing machines and dryers and it's a wonderful thing to have it in my apartment. But many landlords, co-op board and condos don't permit them because of the flooding.
A couple of my friends and I made hot ice for our school science fair. We used sodium acetate. This project won first place at my schools science fair!!! Materials: Stove. Pot. A spoon. A glass cup. and Sodium acetate (you can find it online or in certain heat packs). How to do it: You heat water in a pot and put the sodium acetate in the water.
Dry Ice, Liquid Nitrogen, and Liquid Helium can all be safely used (rather than more volatile substances like liquid oxygen) for extreme cooling. In these cases, an aluminum or copper tube sits directly on the CPU (or GPU or RAM) and is filled with the cooling substance of your choice.