The short answer, both ways
On fuel: run time scales directly with how much propane you are carrying and inversely with how hard the heater is working. A 20 lb tank holds twenty times what a 1 lb camping cylinder holds, so the same heater runs about twenty times as long on it. Turn the output down by half and the run time roughly doubles. That relationship is all you need to plan around, and it is more reliable than any single number, because every heater has a different burner.
On service life: a propane heater that is kept dry will long outlast one that is not, and that difference is measured in years rather than months. The burner is a simple thing — a gas orifice, a venturi and some ports. What dies is everything around it, and almost all of it dies of water.
Run time, in the way that is actually useful
Manufacturers publish run times on the listing or in the manual, and those are the figures to trust for your model — we do not estimate them here. What we can give you is how to think about them:
- Fuel quantity is linear. Twenty times the propane, twenty times the hours. This is why running an all-evening heater on 1 lb cylinders is an expensive habit: a hose to a 20 lb tank costs once and pays for itself in a season.
- Output is inverse. A heater on its low setting can run several times as long as the same heater flat out. On most portables the lowest setting is still enough for one person in a small space.
- Cold weather works against you twice. You run the heater harder, and a cylinder in deep cold delivers gas less readily as the pressure drops. A 1 lb cylinder that gave a comfortable evening in October can feel short in January.
- Wind is the hidden cost outdoors. A patio heater in a breeze is heating the neighborhood. A screen, a wall or a corner will do more for your fuel bill than turning it down.
If run time is the deciding factor in your purchase, buy for tank compatibility rather than for output: the heaters that accept a 20 lb tank — directly or through a hose — are in a different class of practicality from the ones that only take disposable cylinders. Our portable propane heater picks note which is which.
What actually fails, in order
We have not run these units for a decade and will not pretend otherwise. What follows is the standard failure order for consumer gas appliances, and it matches what the parts catalogs for these models are full of:
- The piezo igniter. The click-and-spark unit. Cheapest part on the heater, most frequent complaint, and often replaceable with a screwdriver. A heater that will not light from the button but lights from a match has an igniter problem, not a gas problem.
- The thermocouple or oxygen depletion sensor.This is the safety device that holds the gas valve open only while the pilot is lit. When it ages, the heater lights and then cuts out after a few seconds. Annoying, inexpensive, and absolutely not something to bypass — it is the part that stops the heater filling a room with unburnt gas.
- The hose and regulator. Rubber ages, especially in UV. Replace the assembly rather than nursing it, and test connections with soapy water rather than a flame. This is the one failure on the list with a real safety consequence.
- Burner corrosion. The terminal one. Water sitting in the burner assembly rusts the ports and the flame goes ragged, yellow and uneven. At that point the heater is done. This is entirely preventable and it is the reason the next section exists.
How to make one last
- Cover it, or bring it in. A waterproof cover on a patio heater is the single highest-return purchase in this whole category. Portables should live in a garage or a shed over summer, not under a tarp on the patio.
- Disconnect the cylinder for storage. Store tanks upright and outdoors, never in a basement or a living space. Never store a heater with the cylinder attached in an enclosed space.
- Keep the ports clear.Spiders genuinely do nest in burner tubes and venturis — it is the most common cause of a yellow, lazy flame after a summer outside. A brush and compressed air at the start of the season is a five-minute job.
- Replace the hose on age, not on failure. If the rubber is hard, cracked or sticky, it is finished. Hoses are cheap.
- Watch the flame color. A healthy propane flame is mostly blue with a stable shape. Yellow, sooty or lifting flames mean a blocked port, a bad regulator or a starved air supply, and a heater burning like that produces far more carbon monoxide than one burning correctly.
That is the whole maintenance program. There is nothing else, which is both the good news and the reason so many heaters die young — none of it happens by itself.
When a heater is not worth repairing
Igniters, thermocouples, hoses and regulators are all worth replacing: they are inexpensive and they restore the appliance to new behavior. Rusted burner ports, a corroded control valve or a cracked firebox are not. The test is simple — if the fault is in the fuel path or the flame and it cannot be cleaned out, replace the heater. A gas appliance that burns badly is not a cosmetic problem; it is a carbon monoxide problem.
And if you are tired of the whole category, this is the honest moment to mention the alternative: an electric infrared heater has no combustion, no burner, no igniter, no hose and no tank, so almost nothing on the failure list above applies to it. It will not match propane for raw output in an open or drafty space, which is why the comparison is worth reading rather than assuming. But on a covered porch, it is the longer-lived machine.
