You need to appreciate that an open fire, when drawing correctly, should suck massive volumes of air up the flue, which is what ensures that all the smoke goes the right way. A big open section flue or a cold flue or a dirty or blocked flue won’t draw as well as a hot, small-section, smooth flue, which is why you can get downdrafts and smoking into the room. As the combustion temperature increases so does the power of the rising column of hot gases, which actually creates a slight pressure drop within the room. You need to admit fresh air to replace what the flue is sucking out or you’ll get poor performance and smoking.
The simple answer is to replace the open fire with a wood-burner or a multi-fuel. I think the latter is more flexible because you can burn a wider variety of fuels and with experience you can create a bed of glowing embers, on which to burn your nice dry logs, creating very hot temperatures and nice clean combustion. A wood burner looks nice because it is usually bigger with a better view of the fire but a couple of logs sitting on a grate won’t burn particularly well; you need to create that hot bed of embers to get the best combustion. The best advice I got was to err on the side of a smaller stove, which you will burn harder and therefore hotter and cleaner. Nothing looks worse than an oversize stove, shut down and smoking up the glass. Something like a Dovre 250 is ideal for most houses.
With an open fire, over 80% of the heat goes up the flue. With a stove it’s about the opposite of that and you won’t get those smells and soot in the room. Find a good chimney sweep and make friends with him – he will advise on the best stove for you, where to get it and the best solution for the flue, whether it needs lining or not to create that smooth column of rising hot gases. He will install everything correctly and make provision for sweeping.
If you’re in the North West, Ian at Acorn Chimneys is excellent and Milligans in Burnley are first class for fuel, stoves, stove spares and friendly advice.