Condensation arises because warm air can hold more moisture than cold air. The presence of condensation will be reduced in direct proportion to the increased temperature of the internal walls. When condensation settles on walls and windows, this forms the basis for mould growth.
Mould growth is particularly evident behind furniture where there is insufficient cross flow ventilation present to disperse the natural exhalation being generated by the occupants.
Many domestic and industrial appliances such as gas, oil and kerosene fired stoves, burners and heaters produce large quantities of water as a product of combustion. This problem does not arise with fluid appliances.