Someone somewhere may have an idea. I've been trawling through web sites until I'm thoroughly confused!

The situation is that we have an old oil burner in our future kitchen that is going to be in the way during a "soon to come" phase of our house re-modelling. We have a large oil tank outside to go with it.

We need heat for the central heating system but the hot water and some heat for the central heating may well be coming from our wind turbine installation once we work out where to fit a large tank with immersion heaters and how to fit a bit of kit that switches these in when we are generatng in excess of our normal usage. So it could be a total heat for the house or just a part ot that total that is requred from the burner.

We could buy a new oil burner and put it in the next room (the workshop) without too much problems or plumbing alterations.

Another alternative is to switch to LPG and have a tank for that installed in a different part of the garden.

The oil burner costs more than the LPG burner.

The oil is currently cheaper than the LPG.

It could be useful to have the space clear where the oil tank is and have a shed there in its place. We do have space for a new LPG tank elsewhere.

You can only shop around between LPG suppliers once your initial contract with the first one who installed the tank is complete, so you are stuck with their rates.

You can switch between oil suppliers whenever you want (which we do now).

I'm not considering biomass or wood burners for various reasons and we have ground complications involving water boreholes and land drains when it comes to Ground Source heat pumps.

Any ideas on what is the most cost effective way to go, or pointers to a good way of calculating an accurate forecast of the costs?