Make Your Fireplace Energy Efficient

A pile of burning money.
  • 2-4 hours
  • Beginner
  • 150-300
What You'll Need
Wire brush
Large heavy-duty drop cloth
What You'll Need
Wire brush
Large heavy-duty drop cloth

Fireplaces are a beautiful and fairly inexpensive way to heat a home. They create a wonderfully cozy atmosphere and a dry heat that is a necessity in the winter months. Regrettably, they are also a giant hole in the house. If not properly maintained and used, they can literally suck the heat out of a room when not in use. Even worse, a neglected chimney is a safety hazard. Every fall it is essential to prepare the seasonally used fireplace or wood stove. Simple maintenance ensures peak efficiency.


The first step in preparation for lighting a fire will always be to inspect all the components of the fireplace. Fireboxes and chimneys come in two forms: masonry and prefabricated or factory made. Each type has specific areas of weakness that must be evaluated annually.

Masonry Fireplaces

A masonry fireplace tends to be the most durable and therefore longest lasting option with one major concern: they weigh an average of six to seven tons. This burden on the home, foundation, and ground beneath make them prone to settling. Settling is dangerous because smoke and even flames can escape from a lit fire via cracks in the mortar and fireproof tile to the more combustible materials in the home. In addition, an unlit fireplace suffering from this same issue will allow a multitude of drafts into the home via hairline cracks.

Compounding the problem is the constant expansion and contraction of the heating

Compounding the problem is the constant expansion and contraction of the heating/cooling brick within the firebox. The interior of the firebox can be inspected with a flashlight and any cracked or crumbling mortar must be repaired. Inside the home, check all seams between the firebox and facing materials for any signs of settling. This is the fireplace's weakest point and if the home has a settling issue, it will usually appear here first.

Finally, inspect all of the mortar inside and outside the home, paying special attention to any places joining the materials between the house and stone. Certified chimney sweeps are able to provide this service for a fee and inspections are generally part of their annual cleaning package.

Prefabricated Fireboxes

Prefabricated fireboxes bring their own set of concerns. Again, any seams connecting the fireplace and chimney need to be inspected for signs of separating. Proper installation is key to avoiding many problems with factory units.

Fireboxes and chimneys are built and sold together for proper fit and safety. They must be installed with their matching counterpart. If a homeowner suspects improper assembly, calling a certified chimney sweep is the best way to find out for sure and they will be able to provide directions to move forward.

Next, examine and measure all clearances. These are the small spaces between the

Next, examine and measure all clearances. These are the small spaces between the metal firebox, chimney, and any other house materials. A small grate or trapdoor allows for easy viewing of the firebox while chimney clearances need to be viewed from the attic. All clearances must be at least 2" to provide optimal fire protection.

Create Airflow

Both masonry and prefabricated fireplaces demand quality airflow and workable or tight flue damper seals. Ensuring airflow after almost nine months of no use generally means removing any critters that have moved in and made a home. However, burning wood and/or coal causes soot and creosote to build up on all surfaces within the fireplace.

Removing all these increases efficiency and safety, but also cuts down on the general wear and tear a fireplace is exposed to. For example, animal feces and creosote are both very acidic when mixed with water. Over time condensation and rain will cause this mixture to breakdown seals and mortar.


Cleaning is the simplest and fastest way to increase a fireplace's energy efficiency. Again, a certified chimney sweep can do an inspection and cleaning all at once. Another advantage of hiring a chimney sweep is that they are able to remove all sweepings from the home safely and dispose of them. However, if the homeowner is willing the process is not complicated.

Before beginning, check the state and county regulations for proper disposal of soot and ashes. Some states will not allow this to be collected with the trash or taken to the local waste disposal area.

Prepare the room containing the fireplace by placing a heavy-duty drop cloth on the floor around the fireplace to cover approximately six to eight feet out from the hearth. Move all furniture away from the opening and block all pets from the room.

The nature of a chimney requires a "top-down" approach. Any bird nests, tree debris, and build-up needs to be brushed out with a stiff wire brush. Draw as much as possible from the top of the chimney, but allow gravity to pull the rest into the firebox for sweeping away later. Cleaning the chimney will permit the smoke of a fire to rise quickly and smoothly to the great outdoors. (For more detailed information on cleaning a fireplace, visit our guide.)

While on the roof, take the time to make sure the rain guard is clean and in proper working order. Once debris is loosened it must be removed. Otherwise, it raises the risk of a chimney fire. Next, sweep away any debris from the smoke shelf.

Brush all walls of the firebox and sweep out remaining ash and fragments. If available, use an industrial vacuum for a thorough clean out. Throughout the season, keep a wary eye on the amount of soot build-up in the firebox. Different types of wood create soot faster than others. Once the buildup reaches a depth of 1/4", it is time to repeat the cleaning process.

Per Use Maintenance

Tempered glass doors and an air exchange system ensure the warm air is directed into the room, while sealing off the remainder of any drafts when a fire is lit. At the beginning of the season, make sure the doors are clean and seal properly, and that the fan in the system is in good working condition. Once the fire is well established, close the doors and turn on the fan.

A flue is the best way to seal off the large gaping hole in the roof when the fireplace is not in use. It is a flap just inside the chimney that opens and closes with a simple lever. When the weather begins to cool, check to ensure the lever rotates easily and the damper seals are not in disrepair. A flue damper and seals can be brushed and wiped down in a similar manner as the firebox.

When the fire dies out, close the flue completely to prevent the warm air from t

When the fire dies out, close the flue completely to prevent the warm air from the house escaping. Alternatively, do not ever start a fire with the flue closed. This is extremely dangerous and will quickly "smoke out" the entire house. If it is difficult to start a fire with the damper completely open, it can be permitted to be halfway closed, as long as it is left wide open when the fire catches.