Gas Fireplace Inserts

Natural gas or propane?

Every insert here is built for one fuel or the other. Natural gas runs off a utility line. Liquid propane runs off a tank, burns hotter per cubic foot and uses a smaller burner orifice. The casting, the glass and the log set are usually identical between the two — what changes is the orifice and the regulator. Some models ship with a conversion kit, some are not convertible at all, so buy the fuel your house already runs rather than planning to change it later. The fuel is named on every product page, and where a model is sold both ways you pick it as a variant.

Direct vent or vent free?

A direct vent insert is sealed. It draws combustion air down and pushes exhaust up through a flexible liner inside your existing chimney, so nothing from the fire enters the room. That liner is mandatory, and it is the reason a direct vent installation costs more than the appliance suggests.

A vent-free insert burns room air and vents nothing. No liner, a cheaper installation and more of each BTU stays in the room — but it puts moisture into the house, it is restricted or banned outright in some states and municipalities, and most codes prohibit it in bedrooms and bathrooms. Check your local code before you buy one. Everything on this page is direct vent unless the fit table above says vent free.

Common questions about gas inserts

How much does a gas fireplace insert cost?

Budget $4,000 to $5,500 all in for a direct vent insert. The appliance itself runs $1,959 to $4,738 on this page; the flexible chimney liner kit adds $400 to $900 depending on chimney height; and a licensed installer to run the gas line and drop the liner is typically $600 to $1,500. A vent-free insert needs no liner and lands lower, usually $2,500 to $3,500 fitted. The liner and the labour are the two figures people leave out when they compare unit prices between dealers.

Will an insert fit my fireplace?

Measure the front width, front height and depth of the firebox opening. Most masonry fireplaces built after 1950 take a 25" or 30" insert. The measurement that catches people out is depth — 14" to 15" is the minimum for nearly every model, and shallow prefab boxes often fall short. Measure to the back wall, not to the damper.

Can I run a natural gas insert on propane?

Only if the manufacturer publishes a conversion kit for that exact model, and several on this page do not. A conversion swaps the burner orifice and the regulator, it has to be done by a licensed gas fitter, and doing it with a generic kit voids the warranty on every brand we carry. If your house runs propane, buy the propane version.

What is the difference between a gas insert and a gas log set?

A gas log set sits inside your open fireplace and is mostly decorative: the damper stays open, so most of the heat goes straight up the chimney. An insert is a sealed firebox that replaces the open fire, runs at 70 to 85 percent efficiency and genuinely heats the room. Log sets cost a few hundred dollars, inserts a few thousand. If you want the look, buy logs. If you want the heat, buy an insert.

Do I need a new chimney liner?

For a direct vent insert, yes. A flexible co-linear or co-axial liner runs up the existing flue and every manufacturer here requires it. Budget $400 to $900 for the liner kit depending on chimney height. Vent-free inserts need no liner at all, which is most of their appeal — though they are restricted or banned in some jurisdictions, so check locally before you buy one.

How much heat do I actually need?

Roughly 20 BTU per square foot in a well-insulated house, 30 in an older one. A 27,000 BTU insert comfortably heats a 1,000 to 1,300 sq ft open-plan room. Oversizing is the more common mistake: too much output and you end up running the unit on low, which makes the flame look poor and wastes the money you spent on the bigger model.

Can I install it myself?

The insert itself slides in easily, but the gas line and the liner should be done by a licensed installer, and most jurisdictions require it for the warranty to hold. Expect $600 to $1,500 for installation on top of the unit and the liner kit.

Insert, or a built-in fireplace?

An insert only makes sense if you already have a firebox. If you are opening up a wall or building new, skip this category entirely. A built-in direct vent fireplace costs less installed, vents horizontally straight through the wall, and gives you far more choice of sizes, flame styles and viewing angles.

The honest arithmetic: insert plus liner plus installation typically lands between $4,000 and $5,500. A comparable built-in direct vent fireplace runs $3,500 to $4,500 fitted, because there is no chimney work involved. The insert wins on one thing only — you keep the fireplace and the mantel you already have.

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