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A 1 lb disposable cylinder fits occasional use, a few hours at a time, like a weekend camping trip or an evening in the garage. A 20 lb refillable tank fits regular use, longer sessions, or a heater running for hours at a stretch. The right choice comes down to how often and how long you actually run the heater, not the heater’s BTU rating alone.
The Quick Rule of Thumb
If you use the heater a handful of times a season, for an hour or two at a time, a 1 lb cylinder is simpler and requires no extra hardware. If you run the heater regularly, for several hours at a time, or as a primary heat source for a garage or workshop, a 20 lb tank with a hose-and-regulator kit is more practical and considerably cheaper per hour of use.
Why BTU Rating Alone Doesn’t Decide This
A higher-BTU heater burns through a 1 lb cylinder faster than a lower-BTU one, but that affects how long a cylinder lasts, not which tank size is the right choice. Our how much does it cost to run a propane heater answer covers the cost side of that math. The tank-size decision is really about your use pattern: frequency and session length matter more than the heater’s rating by itself.
When 1 lb Cylinders Make Sense
Simplicity is the main advantage. No hose, no regulator, no refill logistics — just screw on a cylinder and go. This fits infrequent use well: hunting trips, tailgating, the occasional cold evening in a garage. Our 1 lb propane bottle run time guide has the hour-by-hour numbers by BTU rating.
When a 20 lb Tank Makes Sense
Cost per hour drops significantly once you’re buying propane by the pound at refill-station rates rather than paying the per-cylinder markup on disposables. A 20 lb tank also means far fewer trips to swap or refill fuel during a long session. This fits regular garage use, extended camping trips, or any situation where a heater runs for several hours at a time on a consistent basis. Our 20 lb propane tank run time guide covers the numbers, and our 1 lb vs. 20 lb tank comparison covers the full head-to-head decision for indoor heater setups specifically.
Can Every Heater Use Both Sizes?
No. Some heaters, like the Mr. Heater Little Buddy, are built exclusively for 1 lb cylinders with no larger-tank option. Others, like the Big Buddy, can run on either a 1 lb cylinder or a 20 lb tank with the right hose kit. Check your specific model’s fuel connection options before assuming you can switch tank sizes.
The Bottom Line
Match the tank to how you actually use the heater. Occasional, short sessions favor a 1 lb cylinder for its simplicity. Regular or extended use favors a 20 lb tank for its lower cost per hour and fewer refill trips. Check whether your specific heater model supports both before deciding.