Contura stoves have a combustion efficiency that puts them below the permitted limits, provided that you light properly. A wood burning stove is CO2 neutral, because the carbon dioxide produced during the efficient combustion of bioenergy is taken up in the corresponding quantity as new trees are growing.
Always light using dry wood and let the wood lie indoors for at least one day before burning.
Logs are best stored in a woodshed with good air circulation. Split logs dry quicker than unsplit.