It is one of the most frequently asked questions in ballooning: do hot air balloons use helium? The answer is no — and the distinction matters more than you might think. Hot air balloons and helium balloons are fundamentally different machines, based on different principles, using different technology, and offering very different flying experiences.
The confusion is understandable. Both types of balloon float in the sky, both use a large fabric envelope, and both rely on the principle of buoyancy. But the way they achieve that buoyancy could hardly be more different. Let us untangle the two and explain exactly what makes a hot air balloon fly.
The Short Answer: Heated Air, Not Helium
A hot air balloon flies using ordinary air — the same air you are breathing right now — that has been heated by a propane burner. When air is heated, it becomes less dense than the cooler air surrounding it. This density difference creates an upward buoyant force, and the balloon rises.
There is no helium, no hydrogen, and no special gas of any kind inside the envelope. Just air, warmed to roughly 100 degrees Celsius above the ambient temperature. When the pilot wants to climb, they fire the burner to add heat. When they want to descend, they open a valve at the top of the envelope to release some of the hot air. It is elegant, controllable, and remarkably simple.
Where the Confusion Comes From
The mix-up between hot air balloons and helium balloons likely stems from several sources.
First, party balloons — the small, brightly coloured ones that float to the ceiling — are filled with helium. They are many people's first and most frequent encounter with anything balloon-shaped that floats, so it is natural to assume the big balloons work the same way.
Second, the word "balloon" is used for both types of aircraft, even though they are quite different. In aviation terminology, a hot air balloon is formally called a Montgolfiere (after the Montgolfier brothers who invented it in 1783), while a helium or hydrogen balloon is called a Charliere (after Jacques Charles, who launched the first gas balloon the same year). But in everyday language, both are simply "balloons."
Third, weather balloons and scientific balloons — which you might see in news footage rising into the stratosphere — typically do use helium. This reinforces the association between balloons and helium in the public mind.
The history of ballooning is a story of these two parallel technologies evolving side by side, often in competition with each other.
Montgolfiere vs Charliere: Two Types of Balloon
Understanding the difference between the two main types of balloon is straightforward once you know what to look for.
Montgolfiere (Hot Air Balloon)
- Lift gas: Heated ambient air
- Heat source: Propane burner mounted above the basket
- Envelope: Open at the bottom to allow heated air in and cooler air out
- Flight duration: Typically 1 hour (limited by fuel)
- Altitude control: Burner to ascend, parachute valve to descend
- Used for: Commercial passenger flights, sport flying, festivals
This is what you see at balloon festivals, on tourist flights, and in virtually every commercial ballooning operation worldwide. The balloons are large, colourful, and have a visible flame burning intermittently above the basket.
Charliere (Gas Balloon)
- Lift gas: Helium (or historically, hydrogen)
- Heat source: None required — the gas is naturally lighter than air
- Envelope: Sealed (no opening at the bottom)
- Flight duration: Hours to days (no fuel consumed for lift)
- Altitude control: Release gas to descend (irreversible), drop ballast to ascend
- Used for: Long-distance and record flights, scientific research, military (historically)
Gas balloons are far less common than hot air balloons. You are unlikely to encounter one outside of specialised competitions or scientific launches. They can stay aloft much longer than hot air balloons because they do not need to burn fuel to maintain lift, but they are more expensive to operate and less controllable.
Rozier (Hybrid Balloon)
There is a third type worth mentioning: the Rozier balloon, named after Jean-Francois Pilatre de Rozier, who was one of the first people ever to fly in a balloon in 1783. A Rozier balloon combines both systems — a sealed helium cell for baseline lift and a hot air cone for altitude control.
Rozier balloons are used almost exclusively for ultra-long-distance flights, including circumnavigations of the globe. They are extremely rare and not used in commercial passenger operations.
Propane: The Fuel That Makes It All Work
If hot air balloons do not use helium, what do they use? The answer is liquid propane (LPG) — the same fuel used in barbecue grills and camping stoves, though in considerably larger quantities.
How the Propane System Works
The propane is stored as a liquid under pressure in aluminium or stainless steel cylinders, typically mounted inside the basket. A standard commercial balloon carries 2 to 4 cylinders, each holding approximately 40 to 45 litres of liquid propane.
The journey from liquid propane to hot air involves several steps:
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Liquid supply: Propane flows from the cylinder through a flexible hose to the burner assembly, which is mounted on a frame directly above the passengers' heads.
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Vaporiser coil: Before reaching the burner jet, the liquid propane passes through a vaporiser coil — a length of metal tubing that wraps around the burner flame area. The heat from previous burns warms the coil, converting the liquid propane into gas. This is important because gaseous propane burns far more efficiently and cleanly than liquid.
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Metering valve: The pilot controls the flow of propane through a metering valve, usually operated by a squeeze handle or blast valve. This gives precise control over the intensity of the flame.
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Ignition: The vaporised propane exits through a jet and is ignited by a pilot light (a small, constantly burning flame) or by a piezoelectric igniter. The resulting flame is directed upward into the open mouth of the envelope.
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Heat output: A typical balloon burner produces 3 to 5 million BTU (British Thermal Units) of heat energy — roughly equivalent to the output of 1,000 domestic gas hobs running simultaneously. The flame is impressively loud and produces a visible column of fire that can reach 3 to 5 metres in length.
For a more detailed look at the complete system, our guide on how hot air balloons work covers every component.
Fuel Consumption
A typical one-hour commercial flight consumes approximately 100 to 150 litres of liquid propane across all cylinders. This works out to roughly 2 to 3 litres per minute of active burning, though the burner is not running continuously — it fires in short blasts of 2 to 10 seconds, with pauses of 30 seconds to several minutes between burns depending on conditions.
Pilots carry more fuel than they expect to need, maintaining a safety reserve for unexpected situations such as needing to stay aloft longer to find a suitable landing site or to navigate around obstacles. Most flights land with at least 20 to 30 per cent of their fuel remaining.
Dual Burner Systems
Most commercial balloons are equipped with dual independent burner systems — two complete burner units, each with its own fuel supply line and controls. This redundancy means that if one burner system fails, the other can sustain the flight safely. Each burner can be operated independently or together, giving the pilot additional flexibility in managing heat output.
Why Propane Won
Propane is not the only fuel that could theoretically power a hot air balloon burner, but it has become the universal choice for several compelling reasons.
Cost
Propane is inexpensive. The fuel for a typical one-hour balloon flight costs a fraction of what the equivalent amount of helium would cost for a gas balloon. This is a significant factor in making commercial balloon rides affordable for passengers.
Availability
Propane is available virtually everywhere in the world. From rural Morocco to the Australian outback, you can find propane. This makes ballooning practical in regions where exotic gases would be impossible to source.
Controllability
This is perhaps propane's greatest advantage. The pilot can increase lift by burning more propane and decrease lift by burning less (or not at all). The response is predictable and proportional. With a gas balloon, releasing helium to descend is irreversible — once the gas is gone, it is gone. Propane gives the pilot continuous, repeatable control over altitude.
Safety
Propane is flammable, obviously, but it is well understood and safely handled. In the open-air environment of a balloon basket, propane disperses quickly if there is a leak. The fuel systems are designed with multiple safety features: pressure relief valves, blast valve springs that default to "off," and fuel shut-off valves on each cylinder.
Storability
Propane remains stable in its cylinders indefinitely. There is no degradation, no evaporation, and no special storage requirements beyond keeping the cylinders out of direct sunlight (which is standard practice). Helium, by contrast, slowly diffuses through almost any container and is notoriously difficult to store long-term.
Why Not Helium?
If you are still wondering why commercial balloon operators do not simply use helium, here are the decisive factors.
Expense
Helium is a non-renewable resource, extracted from natural gas deposits. Global supplies are limited, and prices have risen substantially over the past two decades. Filling a commercial balloon envelope (2,800 cubic metres) with helium would cost thousands of pounds — and that helium would be lost to the atmosphere after a single flight.
Non-Renewable
Unlike propane, which is produced as a byproduct of natural gas processing and petroleum refining, helium cannot be manufactured. Once released into the atmosphere, it rises to the upper atmosphere and eventually escapes into space. The world's helium reserves are finite, and there is increasing pressure to conserve them for critical applications such as MRI scanners, semiconductor manufacturing, and scientific research.
Loss of Control
As mentioned above, a gas balloon pilot who releases helium to descend cannot get it back. The only way to regain altitude is to drop ballast (sandbags carried for this purpose). Once the ballast is gone, the pilot can only descend. This one-way nature of gas balloon control makes them far less practical for the repeated, predictable flights that commercial passenger operations require.
No Advantage for Short Flights
Helium's main advantage is endurance — a gas balloon can stay aloft for hours or days without burning fuel. But commercial passenger flights last only an hour, and the propane fuel for that hour is cheap and light. There is simply no benefit to using an expensive, irreplaceable gas for a flight that a few litres of propane can handle perfectly well.
What About Hydrogen?
Hydrogen was used in the earliest gas balloon flights, beginning with Jacques Charles's ascent in 1783. It is lighter than helium and was historically cheaper and easier to produce (through chemical reactions with acids and metals).
However, hydrogen is extremely flammable. Several catastrophic balloon accidents in the eighteenth and nineteenth centuries were caused by hydrogen igniting, and the Hindenburg disaster of 1937 — while involving an airship rather than a balloon — cemented hydrogen's reputation as too dangerous for passenger-carrying lighter-than-air craft.
No modern commercial balloon operation uses hydrogen. The risk simply is not worth the marginal lift advantage over helium, let alone over heated air.
The Environmental Angle
Hot air balloons are sometimes praised as one of the more environmentally gentle forms of aviation, and there is some truth to this. A one-hour flight consumes approximately 100-150 litres of propane, producing roughly 150 to 230 kilograms of CO2. For comparison, a short domestic flight on a commercial airliner produces roughly 250 kilograms of CO2 per passenger.
A balloon carrying 12 passengers produces total emissions comparable to just one airline passenger — meaning the per-person footprint is quite modest. And because balloons operate at low altitude in the lower troposphere, their emissions do not have the amplified warming effect associated with high-altitude jet emissions.
That said, ballooning is still a fossil-fuel-powered activity. Some operators are exploring the use of bioLPG (propane derived from renewable sources) as a path to lower-carbon flight, though this is not yet widespread.
Ready to See Propane Power in Action?
Now you know the truth: hot air balloons fly on heated air and propane, not helium. And that is precisely what makes them so controllable, so affordable, and so wonderfully accessible for passengers of all ages.
A sunrise flight over the Palmerie lets you experience the full magic of propane-powered flight — the impressive roar of the burner, the gentle rise into the morning sky, and an hour of silent floating over the Marrakech landscape with the Atlas Mountains on the horizon.
Browse our price guide to find the right flight, or read our first-time flyer tips to know what to expect from takeoff to landing. We look forward to showing you how a little hot air can take you to extraordinary places.