One of the most important features, if not the most important feature, of modern wood burning stoves is their ability to be airtight, to be able strictly to control the intake of air into their combustion chambers. Older stoves, such as the beloved potbelly and Franklin stoves, were notoriously loosely fitted, making it impossible to allow only very little air into the stove.
At first blush it may sound just fine to have a stove that lets a lot of air in and cannot be set to strictly limit air intake. After all, fires need oxygen in air in order to burn fuel (such as firewood) and more air means more fire and, thus, more heat and light. And more is better, right? Actually, no.