Unlined and Direct Connect fireplaces
When inserts were first introduced, many of them were installed without accompanying flue liners, or with partial liners (called “Direct-Connect”) which only went part of the way up the chimney. These installations are no longer considered safe and in many areas it is no longer permissible to install inserts in this way.
When an insert has no liner, or a partial liner, it cannot be cleaned in the normal way (by putting a brush into the chimney through the insert). Doing so would cause ash and creosote to fall behind the insert, where it would build up and potentially ignite. Inserts without full liners must be removed from the firebox before the chimney can be swept, so the sweep can have access to the areas behind the insert and to the top of the insert itself.
Since inserts are usually made of cast iron and often weigh between 400-800 pounds, pulling an insert is a job requiring two technicians and some heavy machinery. Many chimney sweeps will not touch an unlined insert due to the amount of work involved in cleaning it. Others charge extra to service unlined and partially lined inserts.
Barnhill Chimney Company recommends installing a full-length liner for all inserts, and can retrofit stainless steel liners for previously installed inserts which lack them. We use heavywall flexible stainless steel liners, which will not deteriorate even when in contact with corrosive creosote, provide a smooth flue interior which does not promote creosote buildup, and come with lifetime warranties.
A lined insert is much safer, since the smooth walls of the liner do not promote creosote buildup in the flue, and creosote is much less likely to accumulate in inaccessible areas behind the insert. It is much easier to clean, since it does not need to be pulled each time. Lined inserts also burn more efficiently, putting out more heat per cord of wood. The best part is that the liner will pay for itself in just a few chimney sweeps!