Gas fireplace installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What gas fireplace installation is

Gas fireplace installation sets a gas fireplace or insert, runs the gas line, installs the venting, wires any controls and finishes the surround. The installer then tests ignition and the safety shutoffs before the fireplace is used.

Signs you need it

  • You want a fireplace that lights with a switch or remote and needs no wood or cleaning.
  • An existing wood fireplace is being converted to gas, which changes the venting and the gas connection.
  • You are adding a fireplace in a new room or an addition, and there is no gas line near the planned location.
  • The old gas fireplace is past repair, its firebox is damaged or the venting no longer meets its listing.
  • You want a direct-vent fireplace that draws its air from outside and vents through an exterior wall.
  • The gas line in the planned area is too small for the new fireplace, or the gas supply needs a new valve.

What the pro does

  • Check the gas supply, the line size and the location of the shutoff, and confirm the fireplace is listed for the gas type you have.
  • Set the firebox or insert with the correct clearances to combustible materials, and place it on a level base.
  • Run the gas line from the supply to the firebox, with a shutoff valve and a pressure test before the connection is made.
  • Install the venting, either direct vent through an exterior wall or a chimney flue, and set the termination outside.
  • Wire the remote receiver, the thermostat or any wall switch, and connect the power if the unit needs it.
  • Test ignition, the pilot or igniter, the flame pattern and the safety shutoffs, then show the homeowner how to light and shut it down.

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Fireplace size and type, such as a direct-vent insert, a freestanding unit or a built-in firebox.
  • Gas line length and whether a new line or a new valve is needed from the supply.
  • Venting route, including the wall or roof penetration and the termination length.
  • Electrical work for remote receivers, fans or built-in controls.
  • Framing and clearance work needed to fit the unit and meet its listing.
  • Surround and hearth finish, which can range from simple trim to stone.
  • Access to the installation space and the exterior wall or roof for the vent.

What a written quote should spell out

  • The fireplace model and its listing for the gas type and the venting method.
  • Gas line size, length, materials and the shutoff location.
  • The venting method, its length and the termination location.
  • The electrical and control items, listed separately.
  • The clearance dimensions and the surround materials.
  • The ignition and safety shutoff test results, and warranty terms.

Questions to ask before you hire

  • Is this fireplace listed for my gas type, and does the listing match the venting you plan?
  • How will you run the gas line, and what size is it?
  • Will you pressure test the gas line before connecting the fireplace?
  • Where will the vent terminate, and how far is it from windows and doors?
  • Will you test ignition and the safety shutoffs, and show me the results?
  • Who pulls the permit, and will the gas and venting be inspected?
  • What does the warranty cover on the fireplace, the valve and the install work?

Red flags

  • The pro connects a gas fireplace without a pressure test of the gas line.
  • The pro uses a vent that is not listed for the model, or shortens or lengthens the vent without the manufacturer's approval.
  • The pro does not test the safety shutoffs before leaving.
  • The pro cannot show where the gas shutoff is or how the vent terminates.

What you can do yourself

You can clear the room, mark the planned location, and keep the area around the fireplace clear of combustibles during the install. Do not connect or disconnect any gas line, and do not attempt to run or modify a gas connection yourself. Gas line, venting, electrical and ignition work belong to a licensed technician.

Licenses and permits

Gas fireplace installation is commonly done by licensed contractors, and gas line work often requires a licensed trade and a permit with an inspection. Check with your state or local licensing agency for the requirements that apply to your installation.

Gas fireplace installation questions

Can I connect a gas fireplace to my existing gas line?

Only with a licensed installer. The line has to be sized for the fireplace, pressure tested and connected with a shutoff valve. Do not attempt this yourself.

Do gas fireplaces need a chimney?

Not always. Direct-vent models vent through an exterior wall, while others use a chimney flue. The listing for the model tells you which venting is allowed.

Why does the flame look yellow?

A yellow or lifting flame can point to a poor fuel mix, a dirty burner or a venting problem. Turn the fireplace off and call a technician.

Does a gas fireplace produce carbon monoxide?

A properly installed and vented gas fireplace is designed to vent its combustion products outside. A carbon monoxide alarm is still important, and a technician should check the venting and combustion at installation.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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