I think an open fire in a home is indefensible nowadays.
As has been said, a stove is
much more efficient (easily three times more efficient!) than an open fire. There are three main reasons for that:
1. An open fire takes five to ten times as much air from the room as a stove, and all that air has to be replaced with cold air from outside, and then heated.
2. An open fire cannot burn as hot as an enclosed fire, so it produces more carbon monoxide because a hotter fire is needed to convert carbon monoxide into carbon dioxide efficiently. When carbon monoxide burns, it produces heat instead of just going up the chimney and being wasted.
3. An open fire usually produces ten to fifty times more particulates (mostly unburnt fuel) than a stove. That's more kilowatt-hours going up the chimney unburnt and it adds to our pollution of the biosphere.
Stoves vary a great deal in price. I don't think it needs to be expensive to do the job. There are stoves designed to burn only wood, and 'multi-fuel' stove which can burn other solid fuels too. There's loads of advice on the Web already. See for example
http://www.findaproperty.com/displaystory.aspx?edid=00&salerent=0&storyid=21213
You will probably need to line the chimney if you plan to fit a stove (you need to keep the flue gas hot and some old chimneys aren't safe with a stove) but in my opinion it's well worth the expense. In the UK there are various regulations that you need to comply with to fit a stove, see for example
http://www.woodburnerwarehouse.co.uk/installing_a_stove.phtml
We have two multifuel stoves and we cook quite a bit on them. It's more fun than using the cooker, and much more convenient and a lot cleaner than an open fire. It's just like having a great bit hot plate really. There's usually at least one kettle on the stove, and in winter we often don't know what to do with all the boiling water despite using it for making loads of hot drinks, washing, washing up, and filling several vacuum flasks and half a dozen hot water bottles.