NACS strongly recommends that chimneys using the following fuels are cleaned:

Smokeless Fuels: At least once a year

Bitumous Coal: At least twice a year

Wood: Quarterly when in use

Oil: At least once a year

Gas: At least once a year

Biomass: At least once a year

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It is recommended a Stainless Steel Flexible Flue Liner is installed to avoid chimney fires. These types of liner can be suitable for all fuels.