Convert a Gas Insert to a Wood-Burning Insert: What to Know

By Chimney Sweep Directory Editorial Team · Updated 2026-09-07

Gas inserts made sense when gas was cheap and the appeal of a fire without any chopping or ash cleanup was real. But things shift. Gas prices swing. Some homeowners buy a property specifically for the land and want a real wood fire. Others have a gas insert that stopped working and, when they price out the repair, decide it’s time to rethink the whole setup.

The problem is that this conversion is one of the most commonly misunderstood jobs in residential chimney work. Homeowners assume they’re making a simple swap. They’re not. The venting requirements, liner specs, clearances, and even the right to install a wood-burning appliance at all differ fundamentally between gas and wood. Get any of those wrong and you’re looking at a failed inspection, a carbon monoxide hazard, or a chimney fire.

This article goes through what the conversion actually involves, in the order you’ll deal with it: the inspection that has to happen first, the liner work that’s almost always required, the gas line step most people forget, how to pick an insert that will actually pass inspection, and what permits are required. We’ll also flag the regional situations where this project may not be possible regardless of what you’re willing to spend.

Check Your Air Quality District Before You Do Anything Else

This is not the usual disclaimer buried at the end of an article. It belongs first because it can end the project before it starts.

California’s South Coast AQMD and Bay Area AQMD restrict or outright prohibit installation of new wood-burning appliances, including EPA-certified inserts, in many areas. Portions of Colorado, Oregon, and Washington impose similar rules. If your home sits in a Clean Air Act non-attainment area, your local air quality management district may require a variance or exemption even for a certified insert.

Find your local AQMD online and call them directly before you pay for an inspection or get contractor quotes. Some districts have online lookup tools by zip code. This is a 10-minute check that can save you thousands.

Why the Level 2 Inspection Comes First

Once you’ve confirmed your district allows the installation, the first actual project step is a Level 2 chimney inspection. Not a sweep. Not a quick look. A full Level 2 with video scanning of the flue interior.

NFPA 211 Chapter 13 is explicit: a Level 2 inspection is required whenever the appliance connected to a flue is changed or the fuel type is altered. This isn’t optional guidance from the CSIA; it’s a code mandate. The inspection looks for cracks in the flue liner or masonry, deterioration, blockages, and sizing problems that would make the flue unsafe or non-functional for a wood-burning appliance.

The findings matter a lot. Flues that performed adequately for a gas insert may have offset joints, mortar deterioration, or cross-sectional dimensions that won’t work for wood. Wood combustion produces flue gases that can exceed 1,000°F, compared to the much cooler exhaust of a gas appliance. A flue that was marginally acceptable for gas may need significant work before it’s safe for wood. The Level 2 tells you exactly what you’re dealing with before you commit to the full project.

Budget for this inspection separately from the rest of the job. It’s not a line item to skip to save money upfront.

The Liner Question: Why the Old One Almost Never Works

This is the misconception we hear most often. “My gas insert already has a liner. Can’t we just reuse it?”

In almost every case, no.

Gas inserts use aluminum flex liners or low-temperature stainless-steel liners. These are rated for the cooler, less corrosive exhaust of natural gas or propane combustion. Wood is a different animal entirely. Wood combustion produces higher temperatures, creosote, and acidic condensate that destroy a gas-rated liner quickly and can create a fire hazard in the process.

NFPA 211 Chapter 12 requires that liner systems for solid-fuel-burning appliances be listed and labeled specifically for that application. A liner that was acceptable for a gas insert does not meet that standard for wood. The required product is a UL 1777-listed stainless-steel liner, sized to the wood insert manufacturer’s specifications, run continuously from the insert collar to the top of the chimney. ASTM E2558 covers the performance requirements for flexible liner systems, including heat resistance and gas tightness under solid-fuel conditions.

Liner length and the configuration of your chimney (straight runs vs. Offsets) drive cost more than almost anything else on this job. A straight two-story flue runs cheaper than one with a bend. Get quotes from at least two CSIA- or NCSG-certified contractors and ask each one to spec the liner size explicitly in writing.

One more thing: the EPA’s Burn Wise program notes that certified inserts are tested as systems with their manufacturer-specified liners. Installing a different liner than the one the insert was tested with can void the certification and create AHJ approval problems. Your insert manufacturer’s installation instructions govern which liner products are acceptable.

Removing the Gas Insert and Capping the Line

Pulling the existing gas insert out of the firebox is the chimney contractor’s work. Capping the gas supply line is not. That step requires a licensed plumber or gas fitter.

IFGC Section 404 requires that any gas supply line serving a removed appliance be properly capped by a qualified professional. This is not a DIY step and it’s not part of a chimney sweep’s scope of work. If your contractor tells you otherwise, that’s a red flag.

Plan for this coordination explicitly. You may need to schedule the plumber and the chimney contractor on the same day or consecutive days. The gas line has to be capped before the wood insert installation can proceed. Some homeowners are surprised to find they’re managing two separate trades on this project.

The gas insert removal itself includes disconnecting any existing flex liner, pulling the insert unit from the firebox, and inspecting the firebox opening and surround for damage. The firebox dimensions matter for the next step.

Picking the Right EPA-Certified Wood-Burning Insert

Every new wood-burning fireplace insert sold in the U.S. Must meet EPA Step 2 emission standards, which took effect in May 2020 under 40 CFR Part 60, Subpart QQQQ. These are the certified units you’re legally required to buy. The EPA maintains a searchable database where you can verify any model’s certification status before purchase.

Certification matters, but sizing matters just as much, and homeowners get this wrong constantly. An insert has to be matched to your specific firebox opening dimensions and your flue cross-section. Too small and it won’t heat the space or draft properly. Too large and it won’t fit the listing requirements for clearances to combustibles under IRC Section R1006 and UL 1482.

The worst outcome is an oversized insert that the homeowner damps down to avoid overheating the room. Running a wood insert at low-oxygen smolder dramatically increases creosote production. That’s not an efficiency problem; it’s a chimney fire risk.

Have your chimney contractor spec the firebox opening before you shop. Manufacturers publish approved firebox opening ranges for each model. Match those to your actual firebox, not to what looks good in a showroom.

Clearances, Hearth Extensions, and IRC Chapter 10

IRC Chapter 10, Section R1001 specifies minimum hearth extension dimensions for masonry fireplaces. Wood inserts installed into those fireplaces must meet or exceed those dimensions as part of the installation approval. The UL 1482 listing for your specific insert will also specify required clearances to combustibles on sides and top. These govern how close the insert can sit to surrounding framing, mantels, and combustible trim.

Don’t assume that because a gas insert fit the opening without issue, a wood insert of similar external dimensions will pass the same clearances. The listing requirements differ between the two appliance categories. Your installer should pull the actual installation instructions for the insert you’ve selected and confirm the clearances before ordering the unit.

Failing a clearance requirement at final inspection means either modifying the surround or returning the insert. Neither is a cheap fix.

Permits and the Inspection Process

A gas-to-wood conversion requires a building permit in nearly every U.S. Jurisdiction. This is not a like-for-like replacement. Under the IRC, it’s a new solid-fuel-burning appliance installation, and that triggers permit requirements.

The permit application typically requires the insert manufacturer’s installation instructions, liner specifications, and sometimes a site plan or photos of the existing firebox. Your contractor should handle the permit application as part of their scope of work. If they suggest skipping it, find a different contractor.

After installation, a final inspection by the local authority having jurisdiction (AHJ) confirms code compliance and that the installation matches the appliance’s listing. Some jurisdictions layer air-quality permits on top of the building permit, particularly in non-attainment areas that allow wood burning with conditions. In busy permit offices, two to four weeks between application and inspection approval is typical. Factor that into your project schedule.

What This Project Costs and How to Think About It

The cost components are real, and you should understand each one before you call anyone:

• Level 2 inspection before any work starts
• Gas insert removal labor by the chimney contractor
• Gas line capping by a licensed plumber or gas fitter (separate trade, separate quote)
• Liner materials and installation (liner length and flue configuration are the biggest variable)
• Insert purchase price (EPA-certified units span a wide range based on output, brand, and features)
• Permit fees (vary by jurisdiction)
• Final inspection fee if charged separately by your AHJ

Get quotes from at least two CSIA- or NCSG-certified chimney professionals. Ask each contractor to itemize liner specs, liner length, and labor separately from the insert price. That’s the only way to compare quotes fairly.

Regional cost variance is real. Labor rates in the Pacific Northwest and the Northeast run higher than in the Midwest or rural South. Chimney contractors in markets with a lot of insert work (cold-climate regions, mountain communities) tend to have tighter timelines and more competitive pricing. In markets where this work is less common, mobilization costs can push quotes up noticeably.

Finding the Right Contractor for This Work

This is not a job for a general handyman or an uncertified chimney cleaner. The scope involves gas line decommissioning, flue assessment, liner installation, appliance installation to a specific listing, and permit coordination. You need a contractor who is CSIA-certified or holds NCSG credentials, carries proper insurance, and pulls permits as a matter of course.

Certified chimney professionals in Los Angeles who hold CSIA or NCSG credentials will be familiar with your local AHJ’s requirements, which matters because local permit offices interpret model codes differently. A contractor who has done this specific conversion in your jurisdiction is worth paying a slight premium for, because they won’t be learning the local inspector’s preferences on your job.

Ask any contractor you’re considering: “Have you done a gas-to-wood insert conversion in this jurisdiction before?” and “Will you pull the permit?” The answers tell you a lot.

If the Level 2 inspection reveals significant flue damage or sizing issues, the project may need to be staged: repairs or relining first, then insert installation after a re-inspection. Build that possibility into your timeline. Rushing the liner work to hit an installation date is how corners get cut, and a liner job done wrong is the kind of problem you find out about during a chimney fire.

Frequently Asked Questions

Can I reuse my existing gas liner for a wood-burning insert?

Almost certainly not. Gas liners are typically aluminum or low-temperature stainless steel rated for the cooler, less corrosive exhaust of gas appliances. Wood combustion produces flue gases that can exceed 1,000°F along with acidic creosote byproducts. NFPA 211 Chapter 12 requires that the liner be listed and labeled for the specific fuel type, and a gas-rated liner does not meet that standard for solid fuel use.

Do I need a permit to swap a gas insert for a wood-burning insert?

Yes, in almost every U.S. Jurisdiction. A fuel-type change is not a like-for-like replacement under the IRC; it is a new appliance installation that triggers permit requirements and a final inspection by the local authority having jurisdiction. Some localities layer air-quality permit requirements on top of the building permit.

What is a Level 2 inspection and why is it required for this conversion?

A Level 2 inspection includes a video scan of the flue interior to check for cracks, deterioration, blockages, and sizing issues. NFPA 211 Chapter 13 requires it whenever the appliance type or fuel type connected to a flue changes. For a gas-to-wood conversion, the findings directly determine whether the existing flue can support a wood-burning insert at all, and what liner work is needed.

Who caps the gas line when the old insert is removed?

A licensed plumber or gas fitter, not a chimney sweep. IFGC Section 404 requires that any gas supply line serving a removed appliance be properly capped by a qualified professional. Coordinating this trade alongside the chimney contractor is a real project-management step that homeowners sometimes underestimate.

Are wood-burning inserts banned in some areas?

Yes. California’s South Coast and Bay Area air quality management districts, and portions of Colorado, Oregon, and Washington, restrict or prohibit new wood-burning appliance installations, including EPA-certified inserts. Some jurisdictions require a variance if the home is in a Clean Air Act non-attainment area. Check with your local air quality management district before you spend anything on this project.

Does the wood insert have to be EPA-certified?

Yes. Under EPA Step 2 standards effective May 2020, any new wood-burning fireplace insert sold or distributed in the U.S. Must meet emission limits under 40 CFR Part 60, Subpart QQQQ. Only inserts bearing the EPA certification label can legally be sold for residential installation. The EPA maintains a searchable database at epa.gov/residential-wood-heaters where you can verify a specific model.

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