A pellet-burning fireplace insert consists of a metal firebox, a door with heat-proof glass, a decorative flange to cover the gap between the insert and the fireplace, and a new metal chimney liner to carry combustion gases and smoke up through your chimney.
A pellet-burning fireplace insert also has a hopper where you pour in the fuel, which is automatically dispensed to the fire. You can easily adjust the intensity of the fire and the rate at which pellets are supplied to produce as much, or as little, heat as you want.
Some models are thermostatically controlled to keep room temperatures even.
Capacity and cost of pellet-burning fireplace inserts
A pellet-burning fireplace insert heats 1,000 to 2,500 square feet, depending on its size. Talk to your insert dealer about the size of your existing fireplace and what heating capacity you can expect from an insert.
Inserts cost $3,000 to $4,000, including installation and a chimney liner.
Cost of pellet fuel
Pellets typically come in 40-pound bags that cost $3 to $5 each, or about $150 per ton. Homes that use a pellet-burning fireplace insert as a primary source of heating can expect to burn 20 to 40 pounds of pellets per day, or 2 to 3 tons of pellets per year.
Advantages of pellet-burning fireplace inserts
- Because pellets are made from forest or farm waste products, you continue to use a renewable form of energy and help provide a market for materials that might otherwise wind up in landfills.
- You get more heat than you do from an equivalent weight of firewood. Pellet inserts are 78% to 85% efficient, while the best wood-burning inserts are 77% efficient.
- Pellets burn cleaner and produce less creosote than wood, so you don’t have to worry as much about having a chimney fire.
- You can heat as long as a couple of days on a single hopper of pellets, so you don’t have to constantly tend the fire.
- Pellet inserts operate at lower temperatures than wood-burning inserts, so the metal parts aren’t as hot—a safety bonus if you have a toddler.
- A pellet insert can go into a prefabricated fireplace—one with a metal firebox (a wood-burning insert is for a masonry fireplace only).
Disadvantages of pellet-burning fireplace inserts
- Unlike gas and wood inserts, a pellet insert needs electricity to run the automatic hopper, at a cost of about $10 per month.
- You’ll spend about twice as much on pellets as you would on hardwood firewood to get the same amount of heat. But pellets are slightly less expensive than natural gas.
- There may be some heavy lifting. Pellets usually come in 40-pound bags, though you may find 20-pounders.
- Pellet stoves contain finicky parts, so you’ll need annual professional maintenance. Expect to pay $75 to $125 for a checkup.
- If you want to use a pellet insert during power failures, install battery backup or buy a home generator.
- Other biomass fuels—such as corn, nutshells, or dried cherry pits—may be available where you live. Look for an insert that can handle an alternative fuel; many types of alternative fuels are cheaper than conventional pellets.
- If you want to see firewood as well as flames, get a unit with ceramic logs that mimic real firewood.
Tax credits for fireplace inserts
There’s a federal tax credit available until the end of 2011 for fireplace inserts that burn wood, pellets or other biomass fuels, and are at least 75% efficient. The tax credit is good for up to $300 and includes installation expenses.
The federal tax credit expires at the end of 2011. However, certain states may provide tax credits for various types of energy-efficiency improvements, including fireplaces.