Nowadays wood stoves and fires have extremely high outputs and very good combustion rates. The models are well thought out and ensure the wood is burned as efficiently and cleanly as possible. This, unfortunately, cannot be said of the open fire. But why is that?
The first big difference lies in the fact that all contemporary wood stoves and fires are closed, simply by equipping them with a glass window/door. You may perhaps think this will be at the expense of heat output. But nothing is further from the truth! Because the stove is closed, the temperature in the combustion chamber actually rises.
In addition, many models are extra insulated with rear vermiculite walls and the flue gases are fed away via an ingenious labyrinth. This maintains a high combustion temperature and all released matter is burnt to the optimum. This results not only in far cleaner combustion but also in full enjoyment of the heat emitted.
To illustrate: An open fire attains just 15% output as much of the heat is lost via the flue. A contemporary wood stove or fire attains an average output of between 60 and 80%. In addition, the emissions from an open fire as opposed to a good wood stove are many times higher. When both are used to heat a room, the open fire appears to have 15x higher CO emissions than the wood stove, and 50 x more particulate emissions than the wood stove.