Don’t Burn a Hole in Your Pocket: How to Maximize Fireplace Efficiency

Nothing can compare to the feeling of cozying up next to the fireplace, bundled in blankets, with a mug of warm cocoa in cold weather. But this happy little bubble can easily burst when you get your utility bill for the month. Your fireplace may be an energy guzzler without your knowledge.

How is Fireplace Efficiency Measured?

The U.S. Environmental Protection Agency cites two different types of efficiencies for wood-burning appliances, namely combustion efficiency and overall efficiency.

  • Combustion efficiency – The percentage of how well the wood burning device converts the fuel source into useable heat. This doesn’t reflect how much of the produced heat is actually used or transferred to the house.
  • Overall efficiency – The percentage of heat that transfers to space that needs heating as the fuel source burns. This varies depending on factors, such as appliance installation (e.g., chimney height, outside height), operation, and wood moisture, among others.

Overall efficiency is a better measure compared to combustion efficiency because it determines how much of the heat produced from the fuel source is used. Combustion efficiency doesn’t take into account the heat that gets lost due to different reasons. Some manufacturers advertise their fireplaces by saying “90 percent efficient,” but most of the time, they’re pertaining to combustion efficiency.

The problem with older fireplace models is that drafts pull a significant amount of heat out the chimney, because of the hot air’s tendency to rise as it expands. This causes the room to become cooler. If you use centralized heating with a burning fireplace, the heater will work harder to maintain the temperature in the entire house. So even though the fireplace is combustion efficient, it may not rate high in terms of overall efficiency.

Use the Right Wood

wood in the fireplace

Wood moisture is an important factor in fireplace efficiency. Freshly cut wood may contain up to 100 percent moisture, which means the water content weighs more than the wood itself. Building a fire from wet or green wood is less efficient than dried or seasoned wood because much of the energy is spent on warming water to steam. Properly seasoned firewood should contain 20 percent moisture or less.

Dry wood also burns more completely, resulting in a safer and cleaner fire. Wet wood may not completely burn, producing dirty smoke that can form creosote in the chimney. Creosote buildup requires regular and thorough chimney cleaning, otherwise, it can ignite and cause a chimney fire.

Install Fireplace Doors and Inserts

Glass doors can reduce the amount of air that goes out the chimney, making the fireplace more energy efficient. Glass doors are beneficial when you want to keep a fire burning for the night and you need to leave the damper open. But if you’re going to close the damper, keep the glass door open because it can block radiant heat.

Inserts are easy to install into open fireplaces, so you don’t have to change your whole fireplace just to make it more energy efficient. Properly fitted inserts give you a higher level control over the intensity of the fire. Inserts are usually made from steel or cast iron so they provide more insulation to the fireplace and the whole house.

Hopefully, with these tips, you can still enjoy the warmth of your fireplace without worrying too much about your utility bills. Energy efficiency isn’t only beneficial for you and your wallet, it’s also a way to be kinder to the environment. Look into the other parts of your home that may be guzzling energy so you can address the issue immediately.

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