A gas log set is the fastest way to bring a dead wood-burning fireplace back to life. No ash, no hauling wood, no waiting forty minutes for the fire to catch. We have been dropping vented gas log sets into masonry fireplaces across Queens, Brooklyn, Long Island and Westchester for over 30 years, and the same questions come up every time: what size, vented or vent-free, which ignition, and natural gas or propane. This guide answers all of them, including the one that trips up New York City homeowners: vent-free logs cannot be installed inside the five boroughs.
The short answer
Measure the firebox (front width, back width, depth, height), then pick a set whose minimum firebox chart you clear with room to spare. In NYC you need a vented set with the damper clamped open. Outside the city, vent-free is an option where local code allows it. Spend the extra money on a safety pilot or electronic ignition with a remote; match-lit sets are cheaper but you will use the fireplace less.
Key takeaways
- Measure first: front width, back width, depth and height. The set's nominal size is the front log length, and the firebox has to clear the manufacturer's minimum chart with room to spare.
- Vented logs give the most realistic flame and send most of the heat up the chimney. Vent-free logs keep the heat but put moisture and odor in the room.
- Vent-free is prohibited in New York City. Inside the five boroughs you install a vented set with the damper clamped open, or a direct vent gas insert.
- A safety pilot with a remote is the sweet spot. Match-lit is cheapest but has no flame failure shutoff; electronic ignition is worth it if you burn several nights a week.
- Burners are fuel specific. Order for natural gas or propane up front, and in NYC expect natural gas.
- Soot on vented logs is normal. Soot on the mantel or furniture is not, and means a damper, draft or dirty burner problem.
In this guide
- How do I measure my fireplace for gas logs?
- Vented or vent-free? (and the NYC rule)
- Match-lit, safety pilot or electronic ignition?
- Natural gas or propane?
- Which logs look most real?
- How much heat will I get?
- Can I use fire glass instead of logs?
- Does the damper have to stay open?
- What about outdoor gas logs?
- What do owners complain about, and what is normal?
- Our recommended models
- Which should you choose?
- Frequently asked questions
How do I measure my fireplace for gas logs?
Everything else depends on four numbers. Clear the firebox of any grate, ash or old logs, then measure in inches:
- Front width: the opening at the face of the fireplace, side to side.
- Back width: the rear wall, side to side. Most masonry fireboxes taper, so this is narrower than the front.
- Depth: floor of the firebox from the back wall to the front edge of the opening.
- Height: from the floor to the lowest point of the opening, which is usually the lintel or the bottom of the damper frame.
Real Fyre's measuring sheet adds a fifth number, the height at the back wall, because some older fireboxes slope.
The sizing rule of thumb: the nominal size of a log set (18, 24, 30, 36 inches) is the length of the front log, not the space it needs. The burner pan, grate and rear logs take more room, and the flame can never lick brick on the sides or back. Every manufacturer publishes a minimum firebox chart; treat it as a hard floor. Hargrove's Stealth series calls for a 30 inch front width, 20 inch rear width, 14 inch depth and 16 inch height for an 18 inch set, and a 36 inch front and 24 inch rear for a 24 inch set. Napoleon's Fiberglow 18 wants at least 22 inches wide, 18 high and 14 deep. The numbers vary by brand, which is why you measure first and pick the model second.
Between sizes, go smaller. A slightly undersized set still looks like a fire. A crammed set looks wrong, soots the side walls, and can overheat the valve.
From our install team
Measure the back width at the depth where the burner will actually sit, not the very back corner. On a tapered firebox that number decides whether a 24 inch set fits or you drop to an 18. Also note where the gas stub comes in (left, right, floor). A set's valve is usually on the right; a left-hand inlet works but needs a flex line.
Vented or vent-free? (and the NYC rule)
This is the first fork in the road, and in New York City it is not a choice.
Vented gas logs burn inside a working wood-burning fireplace with the damper open. They produce the tall, lazy, yellow flame that looks most like wood because the burner is tuned for looks, not clean combustion. The exhaust, including carbon monoxide and some soot, goes up the chimney like wood smoke would, and most of the heat goes with it. Every set in our vented gas log collection is listed to ANSI Z21.60, the standard for decorative appliances in solid-fuel fireplaces, and the instructions require the damper fixed open.
Vent-free gas logs burn with the damper closed. The burner combusts almost completely, the flame is smaller and bluer at the base, and nearly all the heat stays in the room. They are listed to ANSI Z21.11.2, capped at 40,000 BTU per hour of input, and must have an oxygen depletion sensor (ODS) pilot that shuts the gas off if room oxygen drops. They also put water vapor and combustion byproducts into the room. Model codes limit them to 20 BTU per hour per cubic foot of room volume, bar them as the sole source of heat, and cap them at 10,000 BTU in a bedroom and 6,000 BTU in a bathroom.
In New York City, vent-free is prohibited. The NYC Fuel Gas Code treats vent-free logs and fireplaces as unvented room heaters, and the city does not permit them. If someone offers to install a ventless set in the five boroughs, walk away. We sell vent-free logs and fireplaces to customers in New Jersey, upstate, Florida and other places where local code allows them. For NYC, every job we do is vented logs or a direct vent gas insert. Long Island, Westchester and New Jersey customers should check with the local building department, since towns differ.
| Factor | Vented logs | Vent-free logs |
|---|---|---|
| Damper | Fully open, clamped | Closed |
| Flame | Tall, yellow, most like wood | Shorter, cleaner, bluer base |
| Heat into room | Modest; most goes up the flue | Nearly all of it |
| Typical input | 45,000 to 65,000 BTU/h | Up to 40,000 BTU/h by code |
| Soot | Normal on the logs | Should be none; soot means a problem |
| Moisture and odor in the room | No | Yes, some |
| New York City | Allowed | Prohibited |
Match-lit, safety pilot or electronic ignition?
The ignition system is the decision that most affects how often you will actually use the fireplace.
Match-lit. Simplest and cheapest. No pilot, no valve in the firebox. You open the gas key, hold a long lighter to the burner, and adjust the flame with the key. Hargrove's 24 inch Stacked match light set is a good example: no standing pilot and nothing to maintain. The catch is that nothing shuts the gas off if the flame blows out, so match-lit is only for vented sets, and some jurisdictions and co-op boards will not accept it. We steer customers away from it unless budget is the whole story.
Manual safety pilot (millivolt). A standing pilot with a thermocouple sits under the logs. If the pilot goes out, the valve closes. You light the pilot once a season, then turn the fire on and off at the valve knob. The valve generates its own tiny voltage, so it works with no electricity and can run from a wall switch or a basic on/off remote. This is the workhorse, and it is what most of our customers in older masonry fireplaces end up with.
Electronic ignition. Battery or AC powered, no standing pilot. Press the remote, the pilot sparks, the main burner lights. Most electronic kits ship with a variable flame remote. Real Fyre's G46 burner comes with an electronic pilot and on/off remote or an automatic pilot with a variable remote, and Hargrove's Stealth hidden-control burner includes the variable remote on its electronic models. Thermostat mode, timers and app control live in this tier. The remotes and controls collection has replacement transmitters and receivers.
Our opinion after thousands of installs: safety pilot with a remote is the sweet spot for a vented set. Electronic ignition is worth it if you will burn several nights a week or want flame height control.
Not sure what fits your space? Send us your four firebox measurements and a photo of the gas stub and we will tell you which sizes and burners clear the chart. Book a free design consultation and we will help you narrow it down.
Natural gas or propane?
Gas log burners are fuel specific. The orifice, regulator and even the ember material differ between natural gas and propane, so you pick the fuel when you order. Natural gas sets ship with sand under the burner pan; propane sets use vermiculite, which is why Real Fyre sells vermiculite granules marked for propane only. Propane versions of the same set are rated a little lower (Hargrove's Stealth 24 is 55,000 BTU on natural gas and 50,000 on propane).
In the five boroughs nearly every set we install runs on natural gas. FDNY tightly restricts propane cylinders in the city, and most homes already have a gas line. On the East End of Long Island, in parts of Westchester and New Jersey, and in Florida, propane is common and fine, but confirm the tank and regulator can supply the set's rated input along with everything else on the line.
Which logs look most real?
Two things make a gas fire look real: the flame pattern and the logs. The flame comes from the burner (a single pan, a dual burner with an ember bed, or a tiered burner that puts flame between and behind the logs). The logs come down to material and paint.
Refractory ceramic logs are cast from molds of real wood in a dense ceramic that keeps its detail for years. Real Fyre casts its logs from real wood samples with steel rods inside for reinforcement, and the mass keeps radiating heat after the fire is off. Hargrove's stacked sets use refractory materials rated above 2,000 degrees. Heavy, slow to glow, and the standard for a vented set where realism is the point.
Ceramic fiber logs are lighter, heat up fast and glow sooner. Hargrove's Stealth series uses hand-painted ceramic fiber, and most direct vent fireplaces ship with it for the same reason. They are more fragile, so set them once and leave them.
Concrete (cement) logs show up mostly on outdoor sets, like Superior's Giant Timbers outdoor set, because they shrug off weather. Indoors they are the budget tier with softer detail.
Whatever the material, the paint and ember bed sell the look. Pick a log style that matches what you would actually burn (split oak in the Northeast, birch if you like the white look), and know that birch and other light finishes show soot sooner; Real Fyre says so on its own product pages.
How much heat will I get?
Vented log sets are rated by input, how much gas they burn, not how much heat you feel. Expect 45,000 to 65,000 BTU per hour on an 18 to 36 inch set. Hargrove's Stealth line runs 50,000 on the 18 inch, 55,000 on the 24, 60,000 on the 30 and 65,000 on the 36 (natural gas). Napoleon's Fiberglow 18 is rated up to 55,000. Most of that goes up the chimney; what you get is radiant heat off the logs and firebox, pleasant in the room and not much beyond it. Some burners tilt the heat forward (Hargrove calls this Radiant Riser) and they make a noticeable difference without turning a vented set into a furnace.
Vent-free sets are capped at 40,000 BTU by the standard, and most run 19,000 to 36,000 on a variable valve. Because the heat stays in the room, 30,000 BTU in a tight room is a lot, which is why the room-volume rule exists. Size a vent-free set to the room, not the firebox.
Can I use fire glass instead of logs?
For a modern look, skip the logs and put a contemporary burner under a bed of fire glass, fire stones or river rock. The burner is the important part. A log burner is designed to hide under logs and looks sparse under glass, so you want a linear or pan burner built for media and listed for the application. Real Fyre's indoor and outdoor fire glass is tempered to sit in the flame, and mixes well with Fyre Stones or lava coals. Never use aquarium gravel or glass marbles; untempered glass can pop.
The venting rules do not change with glass. A vented contemporary burner still needs the damper open and a working chimney, and a vent-free glass burner is still prohibited in NYC.
Does the damper have to stay open?
Every vented set we sell ships with a damper clamp, and the instructions require it. The clamp bolts to the damper blade so it cannot close past a set opening. The point is carbon monoxide: a vented log fire makes CO, and with the damper closed it comes into the room. The required minimum opening depends on the set's input and the chimney height; Hargrove's manual publishes a table and tells you to add a permanent damper stop if the included clamp does not fit. Glass doors stay open while the logs burn.
The chimney also needs to draft. If the flue is blocked, the cap is clogged, or a bird has moved in, exhaust spills into the room even with the damper wide open. Have the chimney inspected before the first fire on any fireplace coming out of years of disuse. Our crews do this on every install, and a flue that will not draft is the number one reason for "the logs smell" complaints on a brand new vented set.
From our install team
In a co-op or condo, the board will usually ask for the appliance listing, the installer's license, and confirmation that the damper is permanently fixed open. Have the manufacturer's manual handy; it answers all three. Get the approval before the set is ordered, not after it arrives.
What about outdoor gas logs?
An outdoor masonry fireplace takes a gas log set the same way an indoor one does, but the set has to be built for weather: a stainless steel burner, a valve rated for outdoor use, and logs that will not crack when they get wet and then hot. Our outdoor gas log collection includes Carol Rose's 24 inch Wildwood refractory set (also in 30 inch) and Superior's concrete Giant Timbers. Salt air on Long Island and in Florida eats ignition parts, so a simple safety pilot or match-lit valve is often the right call near the water.
What do owners complain about, and what is normal?
Soot on vented logs. The most common call we get, and almost always normal. A vented set burns a deliberately rich yellow flame, and wherever it touches a log it leaves carbon. Real Fyre says on its product pages that the logs will change significantly in as little as one burn, and the Hargrove manual states that the yellow flame produces carbon monoxide and soot. Many owners like the aged look. If you do not, brush the logs cold or mist the hot logs with water and let the soot carry up the flue. Soot on the mantel, ceiling or furniture is not normal: the damper is not open enough, the chimney is not drafting, or the burner ports are clogged with dust and pet hair. Owners on hearth forums whose set gets sootier after years of service get the same advice: clean the burner, replace the ember bed, have the chimney checked.
Smell with vent-free. Vent-free owners frequently mention an odor, especially on the first burns and whenever the room is dusty or someone has been burning candles; the burner is cooking whatever is in the air. They also mention window condensation and a damp feel after long burns, which is combustion water vapor staying in the room. Short burns, a cracked window and a clean set are the standard advice. In NYC it is moot.
Remote reliability. Most remote complaints we service come down to batteries in the receiver (not the handset), a receiver mounted too close to the burner, or a pairing lost after a battery change. Mount the receiver where the manual says, change receiver batteries every fall, and keep the pairing instructions. A replacement variable flame transmitter is the fix when a handset is actually dead.
Our recommended models
The sets we install most, across sizes, burner types and budgets. All are vented except the Hargrove Weathered Oak, a vent-free set for customers outside New York City.
Vented gas log setsAll log setsOutdoor gas logsFire glass and mediaRemotes and controlsVent-free (outside NYC)
Which should you choose?
Choose vented gas logs if:
- You are in New York City, or anywhere you want the most realistic flame.
- The chimney drafts and you are fine with the damper clamped open.
- Ambiance is the goal and heat is a bonus.
- You want the lowest cost path to a working fireplace.
Choose vent-free logs (outside NYC) if:
- Local code and your building allow unvented appliances. Confirm with the town first.
- Heat is the priority and the room is large enough for the 20 BTU per cubic foot rule.
- You can live with some odor, moisture and shorter burns.
Choose a gas insert instead if:
- You want real heat from a sealed glass front with a blower.
- You are in NYC and heat matters; our gas inserts are the vented way to get it.
- The chimney needs a liner anyway.
For most masonry fireplaces in Queens, Brooklyn, Long Island and Westchester we recommend a vented set with a safety pilot and remote: the Real Fyre Charred American Oak on the G46 burner for a standard opening, the Napoleon Fiberglow when budget matters, the Hargrove Stealth if you want some heat off a vented set. Go to a gas insert if heat is the real goal. Choose vent-free only outside the city and only after the local building department says yes.
Frequently asked questions
Can I put gas logs in my existing wood-burning fireplace?
Yes, if the fireplace and chimney work and a gas line can reach the firebox. A vented set is designed for exactly this. Have the chimney inspected first, and in a co-op or condo get board approval before you order.
Are vent-free gas logs legal in New York City?
No. The NYC Fuel Gas Code prohibits unvented room heaters, which is what vent-free logs and fireplaces are. Use a vented log set or a direct vent gas insert instead. We sell vent-free sets only to customers outside the city where local code permits them.
What size gas logs do I need for my fireplace?
Measure the front width, back width, depth and height of the firebox, then compare against the manufacturer's minimum firebox chart for each size. The nominal size (18, 24, 30 inches) is the front log length, and the set needs a firebox well wider than that. When in doubt, go one size smaller.
Do vented gas logs give off heat?
Some. A vented set burns 45,000 to 65,000 BTU per hour, but most of that goes up the open chimney. You get radiant heat off the logs that warms the room near the fireplace. If heat is the goal, look at a direct vent gas insert.
Is soot on my gas logs normal?
On a vented set, yes. The yellow flame deposits carbon wherever it touches a log, and manufacturers say so in the manual. Brush it off cold or leave it for the aged look. Soot on the mantel or furniture is not normal; that means a damper, draft or dirty burner problem.
Does the damper have to stay open with gas logs?
Yes, for a vented set. The instructions require the damper fixed open, and the clamp that comes with the set does that. A vented set burned with the damper closed puts carbon monoxide into the room.
Can I use my gas logs during a power outage?
Match-lit and millivolt safety pilot sets need no electricity at all. Most electronic ignition sets run on batteries in the receiver, so they also work in an outage as long as the batteries are fresh.
Talk to a specialist
Bring your old fireplace back with the right gas log set
We have been designing, selling, installing and servicing fire features and outdoor kitchens for over 30 years across New York City, Long Island, Westchester, New Jersey and South Florida. Send us your firebox measurements and we will spec the set, the burner and the ignition, then install it and clamp the damper ourselves.
Book a free consultationCall 718-326-4328Showroom: 58-30 Maspeth Ave, Maspeth, Queens.
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Written by the NYC Fireplaces & Outdoor Kitchens team. Last reviewed October 2026. We sell, install and service the products discussed here.
Sources:Real Fyre, Choosing the Right Log, Napoleon Fiberglow 18 specifications, Hargrove Stealth burner installation manual, NYC Department of Buildings, 2022 Construction Codes (Fuel Gas Code), International Fuel Gas Code Chapter 6, Sections 602 and 621. Specifications change; always confirm with the manufacturer's current installation manual.