When you are considering installing a chimney liner, be sure to plan to include proper insulation in your design. You or your installer may be tempted to cut corners by putting a chimney liner inside the flue without insulating it, since it is cheaper and easier to do it that way, but the benefits of chimney liner insulation far outweigh the small cost of doing it properly. Chimney liner insulation offers benefits in terms of improved system safety, increased appliance efficiency and reduced maintenance costs.

Insulation is a key safety factor in your chimney design. A well insulated chimney liner will prevent intense heat from penetrating your chimney’s masonry structure and possibly leaking into your house or attic where it could ignite combustible structural materials. In the event that a creosote buildup inside your flue ignites and causes a chimney fire, an insulated liner is more likely to keep the fire contained inside the flue so it doesn’t spread to your house.

Proper insulation is a critical component of your chimney system design. An insulated flue will keep the combustion gases from cooling off before they are vented out the top of the chimney. A flue with no insulation will be much colder at the top of the chimney than at the bottom, especially in the portion of the chimney that sticks out above the insulated parts of the house. With no insulation, combustion gases will cool off significantly before they are vented outside the building.

Adequate chimney liner insulation will improve the draft of your fireplace or woodstove and thereby increase your system’s fuel efficiency. A chimney liner that is not insulated will not draw as well due to the colder gases near the top of the flue. An insulated chimney liner will also improve your home’s energy efficiency when you are not burning fuel, since the liner will keep cold air from infiltrating through the outside of the chimney and falling down the flue into your house.

Just Like Your Home's Attic, Your Chimney Liner and Chimney Need Insulation

If your chimney was built inside your house so that it is completely surrounded by insulated space, you may be able to use less insulation for your chimney liner near the bottom of the flue, but you will still need to insulate the liner in the portion of its run that extends above your home’s roof or inside an un-insulated attic. If your chimney is placed on an outside wall of your house, then it is crucial that your chimney liner insulation run all the way from the bottom to the top of the flue.

By keeping combustion gases hot until they leave your house, your insulated chimney liner will have less moisture and creosote condensing inside it. This means that your liner will have less creosote deposited inside it and it can be cleaned less frequently than it would need to be if it was not insulated. Less moisture and creosote condensation will not only make cleaning easier and cheaper, but it will also extend the life of your liner since it will be exposed to less corrosive conditions than a liner without insulation would see.

Include the cost of insulation and adequate space for insulation in your chimney liner design. Insulation is a small investment that will pay for itself many times over by making your chimney system safer, more efficient and cheaper to operate.