But for much much shorter periods of time as Microwaves heat considerably faster.

However, heating the water in central heating pipes or immersion heaters still seems feasible. Industrial units that do similar jobs can raise the temperate of liquids from 30c to 200+c in a high flow rate system, with only a few feet of exposure, ie in a matter of seconds. These are 100Kw systems tho, but I would still think that, when scaled down, this method would be more effecient that electric heater coils which require direct contact with water and can only heat the water they touch. It requires convection to take the heat away from the coil, where as microwave can heat it a)quicker and b) evenly.

Yes but in that short period of time a lot more enegy is used, give me a second and I will hunt out the facts, its something like heating your microwave for ten minutes uses the same amount of energy as ..... So it wouldn't work out cost effective at all

Yeah, I'm doing the same. There has to be a very good reason why it isn't being done. Cost might well be that very good reason.

i no that to cook the same food over a year a gas or electirc oven costs £16 when a microwave is only £6.40

Well I know for a fact that heating water is more efficiently done in a kettle than in microwave have that in front of me but cant find anything on the net

It seems that microwaves are used quite considerably in industry for heating and drying purposes (with one of the core reasons being that they are cheaper). Still looking....

Where did you here that? Cause it says microwaves use more or less the same amount of energy as a conventional oven wikipedia

Just remembered, we have a really good "science" type fella on our own forums. I shall ask him to see if he can shed some light on it...

I wish it really was that cheap