Lock-Top Energy Saving Damper


Each Lock-Top Energy Saving Damper fits a Specific Flue Size and Fireplace Size.

You Must Check Size Requirements in the Product Description before Ordering



Traditional dampers are located in the “throat” of a fireplace. They are made of cast-iron and are housed in a low-tech frame work. These cast-iron dampers do not seal well. They have a leaky, rough, metal-to-metal seal. Recent lab studies have shown that even a new throat damper can leak up to $200 of heating and cooling a year. Imagine how much energy an old, rusted out damper leaks!

Lock-Top Energy Saving Dampers seal tightly to save you money. Lock-Tops rubber gasket seals tightly like a storm door for your fireplace, and keeps heating and cooling dollars where they should be…in your home.

Lock-Top Energy Saving Dampers mount on top of your chimney to keep out animals and rain, and easily operates from inside your firebox, sealing tight every time you close it. The Lock-Top damper is constructed of cast aluminum and stainless steel. Stainless Steel is the most popular cap material due to its longevity and flexibility of fuel being burned. This means if you have a wood fireplace and switch to gas logs, the Stainless Steel Cap can handle the change with no concern. A stainless steel cable runs down your chimney flue and easily mounts in the firebox for easy access.

Each Lock-Top Energy Saving Damper is equipped with a unique safety feature that will keep the flue open in case of a chimney fire. As the fire reaches the Lock-top Damper it will melt a lead fastener which will release a safety lock keeping the damper open.

The Lock-Top Energy Saving Damper is available in 6 standard sizes. Each damper is sized to fit specific flue sizes and allow fireplaces with specific cross sectional areas to vent properly. You must pick the appropriate damper for your specific fireplace to vent properly.

Lock-Top Sweep's Ring When installing your Lock-Top Energy Saving Damper, rather than sealing it to the flue tile, an optional Sweep’s Ring can be used. The sweeps ring allows easy removal of the Lock-Top Damper from the flue for cleaning. Just seal the sweep’s ring to the flue, then screw the Lock-Top Base to the sweep’s ring.

When using a Lock-Top Damper on a round flue an RS Adaptor is required. RS Adaptors are available for 6″ through 12″ diameter round flues and work with 8″x8″ and 13″x13″ Lock-Top Dampers. Lock-Top RS Adaptor

Sizing Your Lock-Top Energy Saving Damper

It is imperative that you properly size your chimney top damper. Getting a damper that is too large for the flue tile you are installing it on will prohibit the damper from working. Getting a damper that is too small for your fireplace could cause your fireplace to smoke back into the living area.

Two Steps to Size Your Lock-Top Damper

Step 1

Go to the chimney top and measure the inside dimensions (Width and Length) of the flue tile you will be mounting to. Match those dimensions to the chart below to size your damper.

8″ x 8″ Damper            Fits Inside Flue Sizes–  6″ x 6″ to 9″ x 9″
8″ x 13″ Damper        Fits Inside Flue Sizes–  6″ x 9″ to 9 1/2″ x 12 1/2″
8″ x 17″ Damper        Fits Inside Flue Sizes–  6″ x 14″ to 9″ x 17 1/2″
13″ x 13″ Damper        Fits Inside Flue Sizes–  9″ x 9″ to 12 1/2″ x 12 1/2″
13″ x 17″ Damper        Fits Inside Flue Sizes–  9″ x 14″ to 12 1/2″ x 17 1/2″
17″ x 17″ Damper        Fits Inside Flue Sizes–  14″ x 14″ to 17 1/2″ x 17 1/2″

Step 2

Go to your fireplace and measure the width and height of your firebox opening where you load your wood. Multiply the height x the width. This will give you the cross sectional area of your fireplace. Next, divide this number by 12. This will give you the minimum cross sectional area of the damper you can use. Choose a damper by cross sectional area from the chart below.

8″ x 8″ Damper            Cross Sectional Area 49 Sq. In.
8″ x 13″ Damper        Cross Sectional Area70 Sq. In.
8″ x 17″ Damper        Cross Sectional Area 105 Sq. In.
13″ x 13″ Damper        Cross Sectional Area100 Sq. In.
13″ x 17″ Damper        Cross Sectional Area150 Sq. In.
17″ x 17″ Damper        Cross Sectional Area232 Sq. In.

Additional information

Damper Size

8" x 8", 8" x 13", 8" x 17", 13" x 13", 13" x 17", 17" x 17"


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