There is a growing interest in using geothermal energy, where you can use just plain water to heat your home.
What you need is a system of pipes that are filled with water or if the location dictates anti freeze, this will then go into the ground in a loop and the heat generated through the ground, it is not going to be a lot, so there is a need to add a little heat boost to it.
The water is finally run through an electric heat pump, but because the water is sort of luke warm the amount of electricity needed to heat it, it works out something like for every one unit of electricity you put in, you get three units of heat, producing four units in all.
The science may be a bit “Way out” at the moment, but figures do speak for themselves.
Source [Sensor Metrics]