Using the electric field was indeed possible when megawatt TV stations were still a thing. You could light a tiny bulb or ccfl tube with it. Though at those frequencies you'd need a seriously long loop to heat water. I've been told farmers next to the TV tower would do it with their perimeter fence.
But these days with DVB the big several megawatt VHF towers covering a whole region have been replaced with smaller base stations running only 10-20kW and usually covering the local city area only.
In my country it was just few years ago with this tower.
I don't know sum of power of all transmitters (looks like it was secret information), but I knew few engineers, worked at radio stations and TV channels, who have their equipment installed there, and they talked about tens Kilowatts each one.
So, I think, when analog TV used, total transmission power exceed megawatt, now, yes, they use DVB, and I hear moderate numbers, about 20kW on each base station.
Must say, digital changed world, it give much clearer reception, but lost magic.
But these days with DVB the big several megawatt VHF towers covering a whole region have been replaced with smaller base stations running only 10-20kW and usually covering the local city area only.