Fireplace inserts compared: wood, pellet, gas or electric

What a fireplace insert does

A fireplace insert is a closed heater that slides into the firebox of a fireplace you already have, so the fireplace actually heats the room.

• A wood insert is a wood stove adapted to fit a masonry firebox, and it performs about like a freestanding stove¹².
• A pellet insert burns compressed wood pellets fed from a hopper and can use your existing chimney³.
• A gas insert converts a wood-burning fireplace to natural gas or propane⁴.
• An electric insert sits in the opening and needs neither a chimney nor a vent pipe⁵.

Whether a wood insert beats an open fireplace or a freestanding stove is covered in Wood stove inserts: are they worth it?

The four types side by side

Heat output and efficiency

Wood. Certified stoves burn cleaner and are more efficient than older ones², and Canada's wood-burning code of practice puts pellet stoves at about the same efficiency as advanced wood stoves¹. Watch the label: ads often quote combustion efficiency, while overall efficiency (the heat that actually reaches the room) may be 10 to 20% lower¹⁰. Size matters too: match the insert to the space you want to heat².

Pellet. EPA-certified pellet stoves usually reach 70 to 83% efficiency, with heating capacities from 8,000 to 90,000 Btu per hour across models³.

Gas. Gas fireplaces and inserts in Canada carry a Fireplace Efficiency (FE) rating, and models on the market range from 30 to 70%⁶. Some models are more than twice as efficient as others, so compare the EnerGuide labels before you buy⁴

Fuel cost and availability

Fuel prices swing by region and season, so compare your own local prices rather than a national average.

• Wood is often the cheapest fuel to run: natural gas and propane cost more than wood⁵. It costs least if you cut your own or buy locally by the cord; check how big a cord of wood is before you pay, or look for roadside firewood stands.
• Pellets come in bags you buy ahead and keep dry. Buy pellets certified under a recognized program: PFI in the US, CANPlus in Canada³.
• Natural gas is only an option where there is a gas line on your street. Elsewhere a gas insert runs on

When the power goes out

• Wood needs no electricity to burn. That is why Montreal and Quebec City both let residents use a wood appliance, certified or not, during a power outage of more than three hours (in Quebec City, the appliance must have been declared to the city)¹¹¹².
• Pellet inserts need power for the auger that feeds the fire and the fans. Some models offer a backup battery, and gravity-fed models that need no electricity exist but are less common³.
• Gas inserts with a standing pilot keep working in a power failure⁹. If you want electronic ignition to save the pilot's gas, choose one with a battery backup so it still lights during an outage⁴.
• Electric inserts stop when the power does⁵.

For backup heat in winter storms, wood is the surest choice, then gas with a standing pilot or battery backup.

Venting and installation

• Wood. An insert needs a chimney liner. In Canada, a rigid or flexible liner must meet the ULC-S635 standard, and the insert itself must meet ULC-S628⁸. A certified technician should choose the liner type and diameter⁸.
• Pellet. A pellet insert can vent through your existing chimney³. Follow the maker's venting instructions, and plan for an electrical outlet nearby.
• Gas. The existing chimney must be relined with an approved vent when a gas insert goes in⁹. Direct-vent units are sealed and take no room air for combustion⁹. Vent-free gas fireplaces are not approved in Canada because of indoor air and moisture problems⁹, and the EPA does not support them for the same indoor air reasons². You also need a gas line or a propane tank, installed by a licensed gas fitter.

Maintenance and cleaning

• Wood is the most hands-on: carrying wood, emptying ashes and having the chimney swept every year⁸. A catalytic combustor can last more than six seasons with good care, or fail in as little as two years without it, and non-catalytic baffles and internal parts wear out too¹³.
• Pellet inserts must be cleaned regularly to run safely and efficiently, with a professional cleaning at least once a year³.
• Gas inserts should be inspected before their first use and serviced regularly⁹. CAA-Québec advises having the burners cleaned once a year by a professional⁵.
• Electric inserts need little more than an occasional bulb change⁵.

Emissions and regulations

United States. Since May 15, 2020, new wood stoves must emit no more than 2.0 grams of particles per hour when tested with standard test cribs, or 2.5 g/h when tested with cordwood¹³. Pellet stoves must meet the same limits¹⁴.

Canada. The CSA B415.1-10 standard limits particles to 2.5 g/h for catalytic appliances and 4.5 g/h for non-catalytic ones¹. Quebec has banned the manufacture, sale and distribution of non-compliant wood heating appliances since 2009¹⁵.

Towns can go further. In Montreal, a solid-fuel appliance may be used only if it emits less than 2.5 g/h of particles, whatever the fuel, pellets included. During a smog warning even certified appliances may not be used, while gas and electric fireplaces are not solid-fuel appliances at all¹¹. Quebec City allows only certified wood appliances, already forbids installing new decorative wood fireplaces, and will ban their use from September 1, 2030¹². Check your own town's rules before you choose.

Ambiance

• Wood gives the full experience: the crackle, the smell and the flames you tend yourself.
• Gas gives a steady flame at the push of a button, but no smell of burning wood and no crackling logs⁵.
• Pellet gives a real fire, but it is not the best choice if all you want is ambiance⁵.
• Electric can still create a pleasant atmosphere⁵, with a flame effect made of light.

Which one suits whom

• Choose wood if you have a steady firewood supply and somewhere to store it, want heat that does not depend on the grid, don't mind hauling wood and ashes, and your town allows it.
• Choose pellet if you want to burn wood with as little tending as possible, have dry storage for bags, and either have backup power or can live without the insert during outages.
• Choose gas if you have a gas line or are happy with propane deliveries and want heat with almost no work; pick a standing pilot or battery backup if outages are common.
• Choose electric if you mostly want the look, your chimney cannot be used, you live in a condo or a town that restricts burning, or you only need a little extra heat in one room.

Still deciding on wood? Our guide to choosing a wood stove covers sizing, certification and features that apply to wood inserts too.

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