Can I put a gas fireplace into an existing wood-burning firebox?

Usually yes. A gas insert slides into the existing masonry opening and vents through a liner run up the old flue. The chimney has to be sound and correctly sized for the new appliance, which is why the job starts with an inspection rather than a measurement.

What is the difference between direct vent and B-vent?

A direct vent unit is sealed from the room and draws combustion air from outside through a coaxial pipe, which makes it the most efficient and the most flexible to site. A B-vent unit draws air from the room and vents vertically. Direct vent is the default choice for most installations today.

Are vent-free gas fireplaces allowed?

They exist, but some municipalities restrict or prohibit them and they add moisture to the room. We confirm local rules before specifying one and will normally recommend a vented appliance instead.

How long does installation take?

A straightforward insert into a sound existing chimney is typically one to two days. New construction, a new gas line, or a fireplace being sited where none existed will take longer and may involve other trades.

Does a gas fireplace still need servicing?

Yes. Burners, pilot assemblies, glass seals and venting all need annual attention, and the venting still needs inspection. Gas burns cleaner than wood but the appliance and flue are not maintenance free.

Gas Fireplace Installation

Chimney Monkey installs gas fireplaces, inserts and wood-to-gas conversions across Chicago’s North Shore. We start with the existing fireplace or proposed location, gas supply and venting route before recommending an appliance and installation scope.

Discuss a fireplace installation or call 847-994-4388. Tell us whether this is a new fireplace, an insert or a conversion. We will confirm the assessment needed; diagnostic inspections are paid and repair or installation work is quoted separately.

gas fireplace installation

Which installation fits the project?

New gas fireplace: the location, gas supply, clearances and vent termination determine which systems can be installed.
Gas insert: the existing opening and chimney must be assessed for compatibility with the chosen appliance. An insert is not automatically suitable for every masonry or factory-built fireplace.
Gas log conversion: the firebox, venting and appliance requirements determine whether a log set is appropriate.

From assessment to installation

Review the existing conditions, measurements and intended use.
Define the appliance, venting and finish options, then provide a written installation scope and quote.
Install the agreed system, carry out the applicable start-up checks and explain the controls.

For layout and finish ideas, explore fireplace design. For an existing unit that needs diagnosis rather than replacement, see gas fireplace troubleshooting. If the chimney condition is unknown, an appropriate paid inspection helps establish the next step.

Proudly Serving Chicago’s North Shore

Based in Buffalo Grove, Chimney Monkey serves the North Shore and nearby communities listed below. Contact us to confirm service for your address.

Core Service Areas

Specifically, we proudly serve Evanston, Wilmette, Kenilworth, Winnetka, Glencoe, Highland Park, Highwood, Lake Forest, Lake Bluff, Deerfield, Riverwoods, Bannockburn, Northfield, Northbrook.

Extended Service Areas

We also cover Arlington Heights, Barrington, Buffalo Grove, Des Plaines, Glenview, Hawthorn Woods, & Fort Sheridan.

📞 Call Chimney Monkey at (847) 994-4388 and let us take care of your chimney needs!

What a gas fireplace installation involves

A gas fireplace is an appliance, a gas supply and a vent, and the install is only as good as the weakest of the three. We size the unit to the room, confirm the gas line can carry it, work out how it will vent, and then handle the finish so it looks like it belongs in the house rather than bolted into it. Most of our work is on the North Shore, where the housing stock ranges from 1920s masonry to new build, and those two situations need very different answers.

Direct vent, B-vent and vent-free

Direct vent units are sealed from the room and pull combustion air from outside through a coaxial pipe. They are the most efficient, the safest for tightly built houses and the easiest to site, which is why they are our usual recommendation. B-vent units take air from the room and vent vertically, which suits some retrofits. Vent-free units need no flue at all, but they put moisture and combustion products into the living space and some municipalities restrict them, so we check local rules before specifying one.

Converting a wood-burning fireplace

This is the most common job we do. A gas insert fits inside the existing masonry firebox and vents through a liner run up the old flue. The attraction is obvious: you keep the hearth and the surround, lose the mess, and gain a fire that starts with a switch. The catch is that the old chimney has to be sound and correctly sized for the new appliance, so the work begins with a chimney inspection, and any chimney repair gets done before the insert goes in.

Venting and liners

Gas appliances produce cooler, wetter flue gases than wood. Put those into an oversized old clay flue and they condense, which corrodes the liner and can push moisture back into the masonry. Correct liner sizing is not optional detail work, it is the difference between an installation that lasts and one that quietly damages the chimney.

Finishing the job

Surrounds, hearths and mantels are part of the installation, not an afterthought. See fireplace mantel installation. Once the unit is running we set the flame, check the seals and show you how to operate and service it. Annual fireplace cleaning keeps it that way.

Gas Fireplace Work From Our Job Records

These photos come from our own job records across Chicago's North Shore and nearby suburbs: gas fireplaces, inserts and log sets we have installed or serviced, and log sets as we found them. Each caption names the town and street. We don't publish house numbers.