Hi Pat
No not oil-filled: we have some of those but they cost an arm and a leg to run! The econoheat ones are, I think ceramic panels that radiate heat Apparently they cost about the same as a normal light to run. In Spain they sell for about 79 euros, but we bought English ones at - http://www.tlc-direct.co.uk/Manufacturers/Jeeves/Slim_Heat/ . The only difference is that the Spanish ones have an on/off switch whereas the English ones don't, and they cost us about £30 each.
We've got two in our living room, one in our bedroom and a small one in each of the bathrooms. We've got them on timers which we bought in Aki for less than 4 euros each.
Bye
Irene