Thanks for the reply, Kenny. It's a good day here in Wales (at least in our part!), the best we've had for quite a while. Diesel here is £1.179, but £1.109 at the nearest decent sized Asda - but thats about 150mls round trip. I've also noticed a massive difference in 47kg propane bottle prices as you move around the country. All last summer we could buy it for £32 here, but at the same time saw it on sale in Thurso for over £50. I think it's £43 now. I've always cleaned my boiler flue, and there's never been much to clean, so that might indicate the settings aren't too far off. I'll leave it for now. Can't take advantage of the scheme you mentioned, I've 5 yrs to go still! As regards cost comparisons, I suppose what I'm looking for is pence per B.TH.U. If you have any links to sites which do comparisons along those lines, do send me a PM - thanks! Edit - sutherlandtables website (hope that's not breaking any rules - if so please delete) seems to have all the info. - at a price!

Kenny, did you get any further with your research? I'm in a similar position, no mains gas, so around 11 yrs ago bought and installed an oil fired system. Just bought 1000 litres of 28 sec oil, at 47.65p + 5% VAT. Prices I was quoted varied from 47p (delivered 1st week in April - too late!) to 50.95p. I should imagine you would be paying at least a few pence more than that, given your location - I'm in NW Wales. Just wondering whether it would pay to replace my boiler. It runs perfectly well and has done except for replacing the circuit board for the burner once. Was never professionally comissioned, so may not be set up for the optimum economy. What's needed is the cost of producing one standard unit of heat, with different fuels. I was told the other day (but find it difficult to believe) that electric heating would cost me about half what I pay now. Somebody must have some figures, surely?