Hi Ellen.
I would not advise putting in a wood burner unless you have the time to look after it (by which I mean, loading the fuel and chopping the wood). It is a cheap way of heating your house if you have a ready supply of logs, but what you save in money you will spend in backache, chopping them all summer. It sounds romantic until you actually have to do it. Believe me, I've tried.
I suspect most people with woodburners actually buy pre-prepared wood, which of course is not so cost effective. You still have to load them regularly, of course.
Neither would I advise installing oil or LPG. They may appear comparatively cheap today, but think of it this way: now you are in the rare and privileged position of actually getting to choose how you heat your house, do you really want to choose a fossil fuel? Not only is it environmentally disastrous, it is only going to get more expensive. What seems the cheap option today could be costing you a small fortune in even 5 years from now.
Our house currently has two heat sources; a solid-fuel rayburn, which heats our hot water cylinder by convection, and a coal open fire with a back boiler, which also heats the cylinder by convection but additionally supplies a pumped radiator system. It works well but is a pain, as you have to shovel coal three times a day, and is filthy. Coal is also quite pricey, especially when you can be burning a tonne per month in the dead of winter! The rayburn is a hassle as it's not even in the kitchen any more (the house has been extended) so it's been drained and is up for sale.
As my DW has already posted, we are installing a ground-source heat pump. This draws heat from the ground, concentrates it and feeds it into a cylinder, from where hot water for the taps and radiators is drawn. The science of it is exactly the same as your fridge freezer, which extracts heat from the inside of the cabinet and expels it via that mass of pipes on the back. They get quite hot don't they!
The heat pump is a far more efficient option than a 'wet electric' system. Wet electric would require upwards of 12kW to heat a three-bed semi. A heat pump could do it on about 5kW. So unless your house is tiny, or you don't mind a huge - and I do mean huge - leccy bill, steer well clear of electric boilers.
The biggest downside of installing a heat pump is the high up-front cost. Our system will come in at about £12,000 (although we will only pay £8,000 as there is a 30% grant at the moment, and our cost would be lower if we had sufficient land for trenches to bury the heat collectors - as it is, we have insufficient depth of soil, so have to have a 100m vertical borehole, which is double the cost of 200 metres of 2-metre-deep trench).
Anyway, it's a lot to invest in your heating unless you plan to live there a while and get some of it back in fuel savings. Remember that once it's in, the running costs are absolutely tiny, so you will get that money back. The standard estimate is 10 years; comparing with your current coal system it could be 5 years or less.
The other caution is that there are comparatively few companies supplying heat pumps and even fewer installers. We are having to deal separately with the heat pump supplier (who is also designing and specifying the system), the borehole excavator (and you need planning permission to have that sort of machinery in your garden), the electrician and the plumber. It is all very doable, and I would say extremely well worth doing, but you need to be ready to do the legwork.
If you want more information on heat pumps, our supplier is reputed to be one of the best. Have a look at Invisible Heating Systems' website . Their main business is underfloor heating (which works very well with heat pumps) but they do heat pumps as well. It used to be the case that you couldn't really have a heat pump unless you put underfloor heating in as well, but technology has moved on and now there are models that can get your rads up to 60 degrees c, so you would not have to rip out the existing plumbing and lift your floorboards. All you might have to do is increase the size of the radiators (replacing single panel with double, for example).
If you do opt for a heat pump, I'd be happy to share more details of what we've had to plan and consider over this summer. Ask me by email though, I think I've already posted enough of an essay in this thread. shepherds . house [ a t ] virgin . net