Chimney Cap vs. Top Sealing Dampers

April 25, 2017

If you’ve ever seen the top of your chimney you’ve probably seen a cap or damper covering the chimney flue. These covers are important for the safety of your chimney as well as keeping pests and other issues from occurring inside your chimney and preventing the elements and nature from making way into your home. Depending on the type of fireplace you may have different options when it comes to a chimney cover. The first thing you should know is what each type does

Chimney Cover (also known as a chimney cap:

A chimney cap has several different ways helping your home. The first is that the cap itself keeps the rain from going into your chimney which prevents water getting into your fireplace and causing moisture damage as well as rust. Most caps will also have a wire mesh that prevents wildlife like chimney swifts or squirrels from making homes inside of your chimney. The mesh is also a spark arrestor that prevents sparks or ash from landing on your roof. The cap itself does not close however and because of this it allows smoke or fumes to escape your chimney during use. The downside to this however is because of the inability to close the cap; air can also travel inside the chimney causing drafts inside your home and heat to escape from outside of your home. The inability for a chimney cover to close does work for gas fireplaces however since gas logs produce carbon monoxide, all gas fireplaces must be open at all times.

Throat Damper:

Mostly all fireplaces aside from gas will have a damper somewhere in their chimney system. The options for dampers vary with where the damper is installed. A lot of homes will have what is known as a throat damper which stops air from either leaving or entering the home. The damper is typically more towards the fireplace itself then the top of the chimney. This damper system does however still allow air to flow into the chimney itself which can cause cool air to circulate in the chimney itself. Because of this a throat damper is not typically considered to be the most energy efficient.

Top Damper:

A top damper works very similar to a throat damper. It still prevents air from entering or exiting the home but the advantage to the top damper is that, it seals air off at the top of the chimney which is more energy efficient. Top dampers are cheaper and easier to have repaired or replaced if need be as well. The only thing is that top dampers are not recommended for gas fireplaces since the damper must always remain open. Top dampers do not always include screens but some models do offer screens/ dampers as one unit for a higher price.

What works best for me?

Before purchasing you should look to see what options are available and what would work best for your home. For this reason it is recommended that you have your wood burning fireplace inspected annually to avoid a buildup of creosote. And your gas fireplace inspected annually to make sure your lines are clean and safe. This will allow you to know if you home is ready for installation of a new cap or damper. If you wish to schedule a cleaning or inspection this year, feel free to call or use our website to schedule your next appointment.