What is a common issue with unmaintained wood burning stoves?

A common issue with unmaintained wood burning stoves is excessive smoke production. When a wood stove is not properly maintained, it can lead to inefficient combustion of the wood. This inefficiency often results in the release of more smoke into the atmosphere, which can contribute to air pollution and increase the risk of soot buildup within the chimney. In addition to health hazards associated with inhaling wood smoke, excessive smoke can also indicate incomplete combustion, which not only reduces the stove's effectiveness but can also be a safety hazard due to the potential for chimney fires.

The other options do not accurately reflect common issues associated with unmaintained wood burning stoves. Overheating safety mechanisms are designed to prevent dangerous situations, and if maintained properly, these features should function correctly. Improved energy efficiency and increased heat output are typically the results of proper maintenance and regular use of the stove rather than problems arising from neglect.