Natural gas fire pits run on a permanent line at 7 inches water column and cost roughly $0.96 per hour at 65,000 BTU/hr. Propane fire pits use portable tanks at 11 inches water column and cost about $1.87 per hour. The fuels are never interchangeable — orifice sizes differ — and a natural gas trench rarely repays itself under about 1,400 burn hours.
What's in this guide
- Supply pressure
- 7″ vs 11″water column, NG vs LP
- Cost per hour
- $0.96 vs $1.87at 65,000 BTU/hr (U.S. residential average, EIA, 2025 annual average for natural gas and January–March 2026 for propane)
- 20 lb tank runtime
- ~6.6 hours430,000 BTU, our calculation
- Break-even
- ~1,400 hoursburn time to repay a $1,300 line
What is the actual difference between a natural gas and a propane fire pit?
Three things differ, and only one of them is the fuel.
Pressure. Natural gas arrives at a nominal 7 inches water column; propane leaves a tank regulator at a nominal 11. The Prism Hardscapes Moderno Series manual states “7 inches water column” for natural gas and “11 inches water column +/- 1 inch” for propane. The Outdoor Plus fire pit manual lists the same nominal pair, 7.0″ and 11.0″ W.C.
Energy density. The U.S. Energy Information Administration puts one cubic foot of natural gas at 1,036 BTU and one gallon of liquid propane at 91,452 BTU. As vapor, propane carries roughly 2,500 BTU per cubic foot — about two and a half times natural gas in the same volume.
Permanence. Natural gas is a trench and a permit. Propane is a tank you can move. That is the decision you are actually making.
| Factor | Natural gas | Propane (LP) |
|---|---|---|
| Nominal supply pressure | 7″ W.C. | 11″ W.C. (±1″) |
| Energy content | 1,036 BTU/ft³ | 91,452 BTU/gal; ~2,500 BTU/ft³ vapor |
| Volume at 65,000 BTU/hr | ~63 ft³/hr | ~26 ft³/hr vapor (0.71 gal/hr) |
| Orifice at 65,000 BTU | 4.30 mm | 2.49 mm |
| Fuel cost per hour | ~$0.96 | ~$1.87 |
| Up-front infrastructure | $600–$1,300 line + $100–$300 permit | $0, or the cost of an enclosure |
| Runtime before refuel | Unlimited | ~6.6 hr on a 20 lb tank |
| Movable after install | No | Yes |
| Works in a rental | Rarely | Yes |
| Deep cold | Unaffected | Vapor pressure drops |
Pressures from manufacturer manuals; energy content from the EIA; cost per hour and flow rates are Outdoor Heat Direct calculations.
Why can't you just swap the fuel without a conversion kit?
Because the orifice is a hole sized for one specific gas.
A 65,000 BTU/hr burner must pass about 63 cubic feet of natural gas per hour. To make the same heat on propane it passes about 26 cubic feet of vapor — less than half the volume, at higher pressure. So the propane orifice is drilled much smaller: roughly 2.49 mm against 4.30 mm for natural gas on a 65,000 BTU burner.
Feed propane through a natural-gas orifice and you deliver about two and a half times the intended heat: overfiring, soot, a scorched pan, a flame that lifts off the ports. Feed natural gas through a propane orifice and the burner starves. Propane burners also use an air mixer that natural gas burners do not. Our gas conversion kit spells the parts out: natural-gas-to-propane ships an LP air mixing orifice, coupling and propane regulator with hose; propane-to-natural-gas ships a natural gas orifice, coupling and 1/2″ whistle-free hose.
The expensive mistake: ordering the wrong fuel type and planning to “drill it out later.” Warranties are written against the fuel the unit was built and tested for. Prism Hardscapes tells installers to “verify burner orifice is the proper size for the fuel being used” and to consult the factory. A burner run on the wrong orifice for a season is a warranty denial, not a repair claim.
What does each fuel actually cost per hour to burn?
Residential natural gas costs $15.34 per thousand cubic feet (U.S. residential average, EIA, 2025 annual average). At 1,036 BTU per cubic foot that is about $1.48 per therm. Residential propane costs $2.63 per gallon (U.S. residential average, EIA, January–March 2026).
At 65,000 BTU/hr — typical for a 48-inch fire table, and a fair midpoint if you are still working out how many BTU your fire pit needs — that gives $0.96 per hour on natural gas and $1.87 on propane. The gap is $0.91 an hour.
Burn four hours a week across a 26-week season and you use 104 hours: about $100 of natural gas against $194 of propane. A $94 annual difference. That number is the entire economic case, and it is far smaller than most buyers assume.
Not sure which fuel your patio can take?
Send us your run distance from the meter, your burner size and whether you own or rent. We will tell you which fuel makes sense — including when the answer is “stay on propane.”
Ask our fire feature team Read the full buying guideHow long does a propane tank last on a fire pit?
Shorter than people expect, because fire pits are not grills. A 20 lb exchange cylinder holds about 4.7 usable gallons at the 80% fill limit — roughly 430,000 BTU. At 65,000 BTU/hr wide open, that is about 6.6 hours. Two long evenings. That BTU figure is our own calculation (20 lb of propane × 21,548 BTU/lb), not a manufacturer rating.
Throttle to half output, as most people do once the fire is established, and runtime roughly doubles. A wind guard helps, because it holds a visible flame at a lower valve setting.
| Tank | Usable gallons (80% fill) | Approx. BTU | Hours at 65,000 BTU/hr |
|---|---|---|---|
| 20 lb exchange cylinder | 4.7 | 430,000 | ~6.6 |
| 30 lb cylinder | 6.9 | 635,000 | ~9.8 |
| 40 lb cylinder | 9.2 | 846,000 | ~13 |
| 100 lb cylinder | 23 | 2,115,000 | ~32 |
| 120 gal ASME vertical | 96 | 8,779,000 | ~135 |
| 250 gal tank, above or buried | 200 | 18,290,000 | ~281 |
| 500 gal tank, above or buried | 400 | 36,581,000 | ~563 |
Outdoor Heat Direct calculation: usable gallons × 91,452 BTU/gal (EIA) ÷ 65,000 BTU/hr at full output. Tanks fill to 80% by design to leave room for vapor expansion.
A buried 250 or 500 gallon tank changes everything: natural-gas convenience without a meter, refilled on a schedule. It also costs real money to set and is as permanent as a trench. If you are excavating anyway, price both.
What does it cost to run a natural gas line to a fire pit in 2026?
Budget by the foot, then add the fixed costs.
- Gas line, installed: $15–$25 per linear foot typically, up to $50+ on difficult sites.
- Open trench: $5–$15 per foot. Cheap, but it destroys whatever sits on top.
- Directional boring: $12–$25 per foot, $350–$1,000+ total — two to three times trenching, and worth it under a driveway, finished patio or mature planting.
- Permit: $100–$300 depending on jurisdiction.
- Typical all-in for an outdoor gas appliance: $600–$1,300.
Two things blow that budget. Pipe sizing is the first: natural gas needs about 2.4 times the volumetric flow of propane for the same BTU, so a 1/2-inch branch that suits a propane appliance can be undersized for the same burner on natural gas once the run gets long. Sizing is done against the National Fuel Gas Code, ANSI Z223.1 / NFPA 54, not by rule of thumb.
Meter capacity is the second. If your meter already carries a furnace, water heater, range and dryer, adding a 65,000–150,000 BTU/hr fire feature can trigger a utility upgrade. Ask first. Our manuals and guides library has the documents your installer will want, and local fire pit regulations vary more than people expect.
At what point does natural gas actually pay for the trench?
Nobody publishes this, so here it is. At $0.91 saved per burn hour, a $1,300 gas line needs about 1,429 hours of burn time to break even on fuel alone.
| Usage pattern | Hours/year | Annual fuel savings | Years to repay a $1,300 line |
|---|---|---|---|
| Once a month, 3 hours | 36 | $33 | ~40 |
| Twice a month, 3 hours | 72 | $66 | ~20 |
| Weekly, 3 hours | 156 | $142 | ~9 |
| Twice weekly, 3 hours | 312 | $284 | ~4.6 |
| Four nights a week, 3 hours | 624 | $568 | ~2.3 |
| Nightly, 2 hours | 730 | $664 | ~2.0 |
Outdoor Heat Direct calculation at 65,000 BTU/hr full output, national average fuel prices (U.S. residential average, EIA, 2025 annual average for natural gas and January–March 2026 for propane), $1,300 installed line. Scale linearly: a $2,600 line doubles the last column. Excludes convenience and resale value.
Read the top two rows again. Light the fire pit twice a month and the trench never pays back inside the time most people own a house. Light it four nights a week and it clears in two seasons.
So the decision is not economic. The fuel savings are real but small. Natural gas buys you the elimination of a chore. Propane buys you optionality — the pit can move, come with you, or sit unused for a year at no cost.
Where does the propane tank go, and how much ventilation does it need?
Many fire tables have an integrated compartment — a door in the base, a slide-out tray, a hinged panel. Check the spec sheet for tank access when you browse our propane fire pits and fire tables; compartments are sized around a 20 lb cylinder and nothing larger. If your model has none, you need a separate tank enclosure. Ours run $260 to $682.50, from powder-coated and GFRC units up to cast concrete covers. Cylinders also need their own end-of-season routine — our gas fire pit winterizing checklist covers tank storage, valve position and cover fit.
Ventilation is not decorative. Propane vapor is heavier than air, so a leak inside a sealed enclosure turns it into a bowl of fuel beside an ignition source. Requirements are manufacturer-specific. The Fire Boulder Linear Outdoor Fire manual requires “a minimum of 18 square inches of cross ventilation (per side),” with top openings on the side walls within 5 inches of the enclosure top and a bottom opening of at least 1/2 square inch per pound of propane in the tank. Other makers size venting off burner output — roughly 3 square inches per 1,000 BTU/hr.
What we could not confirm: The Outdoor Plus fire pit manuals we reviewed publish no square-inch ventilation figure for their tank enclosures. Get it from the factory before you build anything around one.
Which fuel should you buy? Here is the honest matrix
| Your situation | Buy | Why |
|---|---|---|
| You rent | Propane | No landlord approves a trench. The pit leaves when you do. |
| You light it under 2× a month | Propane | The line never repays itself. Twenty years at that rate. |
| Vacation or seasonal home | Propane | Propane does not degrade in storage, and there is no standing meter charge for a line you use six weekends a year. |
| You burn 3+ nights a week | Natural gas | Payback in two to three seasons, and no more cylinder runs. |
| Pit sits 10 ft from a gas stub | Natural gas | Short run, low install cost, break-even collapses. |
| Pit sits 80 ft across finished hardscape | Propane | Boring under a patio can cost more than the fire pit. |
| You might reposition the pit | Propane | A gas stub fixes the furniture layout permanently. |
| Built-in masonry surround | Natural gas | It is never moving. Take the unlimited runtime. |
| Selling within 3 years | Propane | Buyers rarely pay a premium for a patio gas stub. |
| You already have a 250–500 gal tank | Propane | 281 to 563 hours between fills. Problem already solved. |
Still weighing formats rather than fuels? Our outdoor fire pit collection, the Prism Hardscapes fire tables guide and The Outdoor Plus guide cover shape, material, size and ignition.
Can you convert a fire pit from propane to natural gas later?
Usually yes, in both directions. The Outdoor Plus fire pit manual states that if you choose a different fuel type, “you can convert your fire pit to use either liquid propane or natural gas any time you wish” — swapping the LP air mix fixture for a natural gas orifice, or the reverse.
What changes: orifice, air mixer, regulator, hose. What does not: the pan, the burner body, the media, the enclosure. Consumer-grade table kits sell around $100–$150; a factory-specified kit for a premium gas burner costs more. Ours is $200 either direction.
The non-negotiable part: this is licensed-technician work. An orifice change alters the appliance's certified fuel category, and a mismatched conversion voids warranty coverage on every brand we carry. If you think you may convert someday, say so at purchase — some models and fire pit kits are far easier to convert than others.
Shop by the fuel you actually have
610 natural gas models and 680 propane models, filtered so you never order the wrong orifice. Free shipping on fire pits and fire tables.
Shop natural gas fire pits Shop propane fire pitsNatural gas vs propane fire pit FAQs
Is a natural gas or propane fire pit cheaper to run?
Natural gas, by roughly half. At EIA residential prices (U.S. residential average, EIA, 2025 annual average for natural gas and January–March 2026 for propane) a 65,000 BTU/hr burner costs about $0.96 an hour on natural gas and $1.87 on propane. Across a 104-hour season that is $100 against $194. The $94 annual gap is real but rarely justifies a $600 to $1,300 gas line by itself.
Can I use a propane fire pit with natural gas?
Not without a conversion kit fitted by a licensed gas technician. At 65,000 BTU the propane orifice is about 2.49 mm against roughly 4.30 mm for natural gas, and propane burners use an air mixer natural gas burners do not. Natural gas through a propane orifice gives a starved yellow flame that will not hold a thermocouple.
How long does a 20 lb propane tank last in a fire pit?
About 6.6 hours at full output on a 65,000 BTU/hr burner. A 20 lb cylinder holds roughly 4.7 usable gallons at the 80% fill limit, about 430,000 BTU. Throttling to half output roughly doubles that. This is our own calculation using the EIA figure of 91,452 BTU per gallon of propane.
What gas pressure does a fire pit need?
Natural gas needs a nominal 7 inches water column; propane needs a nominal 11, usually quoted with a plus or minus 1 inch tolerance. Prism Hardscapes and The Outdoor Plus both publish these figures. Low pressure causes weak flames and pilot dropout, so have your installer confirm delivered pressure at the appliance, not at the meter.
How much does it cost to run a gas line to a fire pit?
Typically $600 to $1,300 all-in, at $15 to $25 per linear foot. Open trenching adds $5 to $15 per foot; directional boring under a driveway or finished patio runs $12 to $25 per foot. Permits add $100 to $300. Long runs and loaded meters can push the total well past that range.
Does propane go bad if I do not use my fire pit for a year?
No. Propane does not degrade or lose potency in storage, unlike gasoline or diesel. The cylinder is the limiting factor: U.S. DOT rules qualify most portable cylinders for 12 years from the manufacture date, then require requalification roughly every five years. That stability makes propane the sensible choice for a seasonal or vacation property.
Do I need a tank enclosure for a propane fire pit?
Only if your model has no integrated tank compartment. Many fire tables hide a 20 lb cylinder in the base behind a door or slide-out tray. If yours does not, a matching enclosure keeps the tank out of sight and weather. Ventilation is mandatory either way, because propane vapor is heavier than air and pools in a sealed box.
How much ventilation does a propane tank enclosure need?
Follow your manufacturer's manual, because the figures differ. The Fire Boulder Linear Outdoor Fire manual requires a minimum 18 square inches of cross ventilation per side, top openings within 5 inches of the enclosure top, and a bottom opening of at least 1/2 square inch per pound of propane in the tank. Other makers specify roughly 3 square inches per 1,000 BTU/hr.
Why does natural gas need a bigger pipe than propane?
Volume. Natural gas carries about 1,036 BTU per cubic foot; propane vapor carries roughly 2,500. Delivering 65,000 BTU/hr means passing about 63 cubic feet an hour of natural gas against about 26 of propane, roughly 2.4 times the flow. That is why a 1/2-inch branch adequate for propane often becomes a 3/4-inch line on natural gas.
Which fuel is better for a fire pit on a deck?
Either works, but propane avoids drilling a gas penetration through deck framing. Fuel choice does not change clearance requirements, which come from the manufacturer's manual and vary widely, from 36 to 48 inches at the sides. Check the deck material and the clearance table for your exact model before you pick a location.
Sources. Gas supply pressures: Prism Hardscapes Moderno Series and The Outdoor Plus fire pit installation manuals. Fuel energy content (1,036 BTU/ft³ natural gas, 91,452 BTU/gal propane, 100,000 BTU/therm): U.S. Energy Information Administration. Residential fuel prices: natural gas $15.34 per thousand cubic feet (U.S. residential average, EIA, 2025 annual average) and propane $2.63 per gallon (U.S. residential average, EIA, January–March 2026). Enclosure ventilation: The Fire Boulder Linear Outdoor Fire installation manual. Installation costs: 2026 HomeGuide and Angi contractor cost data. Cylinder requalification: U.S. DOT.
Our own calculations, marked throughout: cost per burn hour, seasonal fuel cost, volumetric flow rates, all tank runtime figures and every break-even number. These assume full burner output at 65,000 BTU/hr and national average fuel prices; local rates will move them.
Not verified: The Outdoor Plus does not publish a square-inch ventilation requirement for its propane tank enclosures in the manuals we reviewed. Contact us and we will request it from the factory.
All gas line work, orifice changes and fuel conversions must be performed by a licensed gas technician in accordance with the National Fuel Gas Code, ANSI Z223.1 / NFPA 54, and local code. Outdoor Heat Direct prices are current at publication and subject to change.