How long does a 20-lb propane tank last on a fire pit, and what does that work out to per evening?
A 20-lb cylinder holds about 4.7 gallons of propane — roughly 430,000 BTU. A 60,000 BTU pit like Napoleon's Uptown drains it in about seven hours at full blast, or four to five three-hour evenings at a moderate flame. Divide what you paid for your last refill by those evenings and you've got your true per-evening cost.
The tank math, straight
Start with 430,000 BTU in the cylinder and divide by how hard you run the burner. Wide open at 60,000 BTU, that's about seven hours — call it two long evenings. At a half flame around 30,000 BTU, closer to fourteen hours, which is where the four-to-five-evenings figure comes from, and most nights are a mix: tall flame early, turned down as the conversation settles in. One wrinkle worth knowing: tanks often feel like they die early because a nearly empty cylinder on a cold night can't keep its pressure up — the flame goes limp before the fuel is truly gone. Anyone who's run a pit through an October evening in the mountains has watched it happen.
When swapping tanks stops being charming
A 20-lb tank is a fine way to find out you love your fire pit — and a tedious way to keep loving it. The upgrade is a permanent fuel supply: a buried, outdoor-rated line from your natural-gas meter if you're on the Asheville or Hendersonville mains, or from your existing propane tank out in Fairview, Candler, or Brevard country. No swaps, no dead cylinder mid-gathering, and the burner gets the steady supply it's rated for, which small cylinders can struggle to deliver in cold weather. In North Carolina, running that line is licensed gas work: we trench, pipe, permit with your county, pressure-test, and meet the inspector.
Per-evening cost in the real world
Whatever a refill or exchange costs you, the honest arithmetic is that price divided by roughly four evenings at a moderate-flame pattern. Plumbed fuel generally undercuts cylinder propane per BTU — which is why patios that get a dedicated line almost never go back to tanks. If you're weighing the upgrade, call (828) 545-0525 for a free assessment; we'll quote the line and the burner as one permitted job.
Related questions
- How much does it cost to run a gas fire pit per hour?
- Is it cheaper to rent or buy a propane tank for a fireplace?
- How much does it cost to set up propane for a fireplace if I don't have natural gas — tank, line, and all?
- How much does a gas fire pit cost?
- How much does it cost to run a gas line to an outdoor fire pit or patio, including trenching?
- How much does a gas fireplace cost installed?
Still deciding? Talk to a real installer.
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