Chimney liners are made from two different types of materials
based on there use. Chimneys that vent oil furnaces or wood burning
appliances such as wood stoves, require stainless steel liners. This
is because of the higher flu temperatures and corrosive byproducts.
Chimneys that vent gas appliances can save costs and use an aluminum
liner because the the temperatures are not quite as high. Stainless
steel can also be used with gas to increase longevity.