I have been told that I should install a chimney liner because I have a fuel burning furnace. Is this really neccessary?
Code requires that chimneys of fuel burning appliances (including furnaces and water heaters) be lined except in certain cases. Over the years, older, unlined chimneys have deteriorated just from age. The newer, high efficiencies furnaces lose less heat up the chimney and the cooler exhaust temperatures will further damage the chimney. When we have an earthquake the weakened chimneys area the ones that are damaged.