Tips for Buying a Fireplace Insert - Part 2 of 2

Here's how to turn your masonry-built wood fireplace into a heating powerhouse!
NDI35 gas insert

Does your home have a masonry built, open-burning wood fireplace? If you answered yes, it’s most likely highly inefficient. Explore your options in this two-part blog series! In Part 1, on April 26th, we covered the basics, including “fireplace inserts 101,” and types of inserts. In Part 2 below, we’re digging in deeper with performance, installation and fuel considerations.


What makes a fireplace insert so much more efficient than your open, wood-burning fireplace? In a nutshell, it boils down to design and technology, but here are details.

Gas Fireplace Inserts. Many are AFUE rated (annual fuel utilization efficiency), which means they’re tested to the same standards as furnaces. Direct vent gas fireplace inserts have sealed combustion systems that expel 100% of exhaust outside the home, keeping indoor air safe and clean. Technologies like IntelliFire™ significantly boost efficiencies and heat output.

Wood Fireplace Inserts. EPA-certified wood fireplace inserts can be up to 78% efficient. Today’s burn technologies provide a clean burn, expelling minimal pollutants into the outside air, with some models producing as little as 3.1 grams per hour.

Pellet Fireplace Inserts. Today’s pellet inserts have state-of-the-art technology that produces steady, regulated heat for many hours on a single load of pellets. Due to pellet density and high burn efficiencies, pellet inserts emit minimal low outside air particulates.


The cost of adding an insert, including installation, can be as low as $2,900 for gas and wood-burning units, and $3,200 for pellet-burning inserts (actual costs vary by area of the country and model chosen). For safe and reliable installation, we recommend professional installers certified by the National Fireplace Institute®. They will also obtain necessary permits and arrange required inspections. When choosing an insert, a professional hearth dealer will offer the best guidance.

Gas Fireplace Inserts. The firebox is outfitted with two separate flexible liners (pipes) that are run parallel to each other up the existing chimney, which terminates above the roof. One liner expels the fire’s combustion and the other brings in combustion air needed to feed the fire.

Wood Fireplace Inserts. The firebox is outfitted with a stainless steel, flexible single liner (pipe) that is run up the chimney and terminates above the roof.

Pellet Fireplace Inserts. The firebox is outfitted with a hybrid stainless steel vent system that runs vertically up the existing chimney, terminating to the outdoors above the roof.


Fireplace inserts are available for natural gas/liquid propane, wood, and pellets. When choosing what fuel is right for you, consider fuel cost and availability, desired heat output, and the level of interaction and maintenance you want.

To Summarize…

Gas Fireplace Inserts:

  • Direct vent gas models expel 100% of exhaust outside the home
  • Some gas inserts are AFUE (annual fuel utilization efficiency) rated and tested to the same standards as furnaces

Wood Fireplace Inserts

  • Some models are up to 77% efficient
  • Advanced burn technology allows homeowners to get the most heat out of the wood they harvest or purchase
  • They produce minimal emissions and very low levels of particulates
  • Heating bills can be significantly lowered, especially for those with central furnaces fueled by heating oil or propane
  • Homeowners can efficiently and responsibly burn wood, which is a renewable fuel

Pellet Fireplace Inserts

  • Pellet inserts expel extremely low particulate emissions due to high burn efficiency and the density of the pellet fuel
  • Depending on the size of the stove and the floor plan, it is possible to heat up to 2,500 square feet with a pellet insert
  • According to the Pellet Fuels Institute, burning one ton of pellets instead of oil reduces carbon emissions by nearly 1.5 tons.
  • Pellet inserts help homeowners get closer to “living off the grid” and produce less greenhouse gases than fossil fuel systems

Upgrading your open masonry built wood fireplace with an insert will make your home more efficient, can help to save money, and transform the fireplace into an efficient heating unit.

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