Difficult. We have oil warm air heating. When we moved here in 1986, we assumed we would have to shell out for a new heating system, but managed to sort this system out. And CLKD, it doesn't create a draught! It's great and very efficient in drying washing in the winter. My sister had gas warm air heating, which was not efficient. Our boiler is enormous, but housed in the large garage and heating engineers (chosen with care) seem determined to keep it going. Apparently, they don't make them like they did in the old days! (40 years old). But one day it will stop never to go again and then we will have to make a decision on what kind of heating system to install, so I will be interested in your research. We don't have access to gas, but do have room for a tank.