Fireplace Insert or Freestanding Stove?

Same fire, different box

In the U.S. EPA's words, an insert works and performs much like a freestanding wood stove; the difference is that it is built to go inside the firebox of a fireplace that is already there, masonry or metal. The Department of Energy makes the same point from the other side: a well-fitted insert can function nearly as efficiently as a wood stove.

So the choice is rarely about combustion. It is about the house: which room needs heat, what the existing fireplace is, how much floor you can give up and what the chimney will need. The questions below go in the order that usually settles the decision fastest. Our overview of fireplace inserts covers wood, gas and pellet inserts in general. This guide stays with wood and with one question: insert or stove.

Question 1: Where do you actually need the heat?

The Department of Energy calls most wood and pellet appliances essentially space heaters, to be placed in the room where you spend most of your time. That single point decides many cases.

• The fireplace is in the room you live in. Keep going; an insert is a real option.
• The fireplace is in a formal living room nobody uses, and the family lives in a kitchen or den elsewhere. An insert would heat the wrong room. A freestanding stove in the room you use, with its own chimney route, is worth pricing even though it means more construction.
• You want heat on a lower floor or in an addition. Only a freestanding stove can go there, and it will need a chimney. Where there is no masonry chimney, that usually means a listed factory-built chimney installed with its own parts, as described on our wood stove installation page.

If the fireplace room is the right room, the next question is whether the fireplace itself can take an insert.

Question 2: What kind of fireplace do you have?

Wood inserts are built for specific kinds of fireplaces, and their manuals say so. Blaze King's manual for its Princess insert, as one example, states that the insert may not be installed into a factory-built fireplace, must go into a code-complying fireplace, and that no bricks or mortar may be removed from a masonry fireplace to make it fit.

• Masonry fireplace in sound condition: go on to Question 3.
• Factory-built (prefab) fireplace: an insert is possible only if both the fireplace maker and the insert maker allow that combination. Many owners in this position end up with a freestanding stove on its own chimney, a gas appliance approved for the unit, or a replacement fireplace. See factory-built fireplaces: care and limits.
• Masonry fireplace with damage: a cracked firebox, a deteriorated smoke chamber or a failing crown has to be dealt with before any insert goes in, since the insert will hide the firebox from view.

If you cannot tell which kind you have, the clues are listed in masonry vs. factory-built chimneys.

Question 3: Does it fit the opening and the room around it?

An insert has to fit inside the firebox with room for its liner connection. Manuals publish a minimum opening. The Princess insert manual lists a minimum fireplace opening of 25 3/4 inches wide, 23 1/2 inches high and 12.5 inches deep. A shallow or oddly shaped firebox can rule out a model, or every model, before anything else is considered.

The space around the fireplace matters just as much. Insert manuals set clearances to mantels, trim and side walls. The same manual calls for a mantel shelf at least 26 inches above the top of the insert's door flange and side walls at least 17 inches from the flange, with floor protection extending 16 inches in front (in the U.S.) and 8 inches to either side of the door opening. A low wood mantel that was fine for an open fire can be the obstacle for an insert.

A freestanding stove brings its own footprint. Jøtul's manual for its F 400 stove calls for noncombustible floor protection extending at least 16 inches in front of the stove and 8 inches from the sides and back, for a minimum of 42 by 44 inches. Add the stove's clearances to walls and furniture, and a freestanding stove often claims a good share of a small room. These figures are examples from two manuals; your appliance's manual sets its own numbers. Our guide to clearances to combustibles explains how they work.

Question 4: How do you want the heat to reach you?

A freestanding stove stands in the room with its top, sides and back exposed, so it gives off heat in every direction. That radiant heat is what you feel on your face from across the room.

An insert sits inside masonry. Its back and sides face the old firebox, so the useful heat has to come out the front. Inserts are designed around that, and many move warmed room air out through the front with the help of a fan. On the Princess insert the blower is optional and runs on household current, 115 volts. If you want a fan-assisted insert to keep moving heat during a power outage, plan on the blower being off; the fire itself does not need electricity.

The Department of Energy adds a point that applies to both: inserts should be as airtight as possible, because the more airtight they are, the easier it is to control the fire and its heat output. A gap between insert and fireplace, or a surround that does not seal, works against that.

What changes in the room

A third arrangement sits between the two: a freestanding stove set on the hearth in front of the fireplace, venting up the old chimney. It keeps the radiant heat of a stove while using the existing flue. Stove manuals and codes do not accept simply blocking the fireplace opening and ending the stove pipe inside the firebox; the stove has to connect to a liner. See how a wood stove should be vented.

Question 5: What will the chimney need?

The chimney work is often similar for both and is a large part of the project.

• Insert: modern manuals require a dedicated liner from the insert to the top of the chimney. The Princess manual calls for a 6-inch stainless liner listed to UL 1777 (or the Canadian equivalents), continuous from the appliance to the chimney top. It also allows the damper plate to be removed only if that will not weaken the structure.
• Stove on the hearth: the same idea, with the connection made where the stove pipe enters the fireplace or chimney.
• Stove elsewhere: either an existing flue in good condition that the stove alone will use, or a new factory-built chimney.

Whatever the route, the Department of Energy notes that the flue size should match the appliance outlet, because an oversized flue slows the exhaust and increases creosote. Adding an appliance is one of the triggers CSIA lists for a Level 2 inspection. On our visits for a planned stove or insert, we look at the fireplace and chimney with a camera when the flue allows, check the roof and attic when it is safe, and show you photographed findings before anything is put on the schedule. See inspection before a new appliance.

Question 6: How will it be serviced in ten years?

Both appliances need the same yearly attention: inspection, sweeping when deposits call for it, and checks of gaskets, baffles and, on catalytic models, the combustor. The difference is access.

A freestanding stove is open on all sides. The connector can be taken down, the stove can be looked over from every angle, and the chimney connection is in plain view.

An insert hides the old fireplace and the base of the liner. Sweeping is usually done through the liner, often from the top. A close look at the firebox, smoke chamber and liner connection behind the insert may require sliding the insert out, which depends on how it was installed. Ask before installation how the insert can be removed for service, and keep the installation paperwork and the manual with the house records.

If you are also weighing burner types, see catalytic vs. non-catalytic stoves; both inserts and freestanding stoves come in each design.

Questions homeowners ask

Sources

1. U.S. EPA Burn Wise: Choosing Appliances
2. U.S. Department of Energy, Energy Saver: Wood and Pellet Heating
3. Blaze King: Princess insert (PI29) owner's manual (PDF)
4. Jøtul: F 400 Castine installation and operation manual (PDF)
5. Chimney Safety Institute of America: Chimney inspection levels

This guide is general information. It can't diagnose a specific chimney; an inspection can.