Guide
Constant-air vs sealed vs helium inflatables
A constant-air inflatable stays up as long as its blower runs; a sealed-air inflatable is inflated once, closed with valves and needs no socket; a helium inflatable floats, because one litre of helium lifts 1.02 g. The choice depends on available power, how long it must stand and whether it has to fly. For the Buttonscarves giant bag, Digital Inflatables combined constant air and sealed air.
Contents · 6 sections
What is the difference between constant-air, sealed-air and helium inflatables?
A constant-air inflatable is fed all the time by a blower that replaces the air escaping through the seams; a sealed-air inflatable is inflated once and closed with valves; a helium inflatable is sealed too, but filled with a gas lighter than air.
Constant air suits large volumes and complex shapes, because the blower keeps the pressure up despite leaks. It is usually how player entrance tunnels work, like the custom inflatable sport tunnel.
Sealed air suits more compact objects that must stand without a cable or any noise. Both can be combined: the Buttonscarves giant luxury bag, 14 m by 8.5 m high and fully lit, uses constant air and sealed air.
Does the blower have to run all the time?
Yes for a constant-air inflatable, which deflates as soon as the blower stops; no for a sealed-air or helium inflatable, which is inflated and then unplugged.
A constant-air inflatable therefore needs a socket nearby, or a generator. The canton of Graubünden, for example, lends an inflatable arch 8 m wide and 6 m high for events, provided a 230 V power connection is available.
Without a socket, sealed air solves the problem: the Haut-Bugey Agglomération totems and arch are inflated with a small 12 V pump, with no 220 V socket.
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Request a quoteHow long do inflatables stay inflated?
A constant-air inflatable stays inflated as long as its blower runs. A sealed-air or helium inflatable slowly loses pressure or gas through its valves and seams, so it is checked and topped up during the display.
Helium adds a running cost, because the gas is lost when the inflatable is deflated. According to the USGS, the base price of Grade-A helium was about $14 per cubic metre in 2024, before surcharges, and helium is seldom recycled in large-volume uses.
For Mosaert, the label founded by Stromae, Digital Inflatables made a 6 m giant cloud filled with helium, installed in Montmartre, Paris.
How much power does a blower use, and is it noisy?
Power depends on the volume to keep up: for the 2 m and 4 m diameter moons made for WAY agency, Digital Inflatables specifies a blower of only 120 watts.
A blower can be heard: for its inflatable park in summer 2026, the town of Pont-Audemer asks for blower noise to be reduced as far as possible with anti-noise covers.
Near the audience, move the blower away or hide it behind the set while keeping its air intake clear. Where silence matters, in a theatre or a shop window, sealed air and helium avoid any fan noise.
What happens to an inflatable in a power cut?
A constant-air inflatable starts to deflate as soon as its blower stops; a sealed-air or helium inflatable is not affected.
For inflatable play equipment, the UK HSE asks for this to be tested before each use by switching the blowers off: the inflatable must deflate slowly enough for users to get out safely, and the non-return flap on the blower outlet is checked daily.
For a large volume open to the public, plan emergency power: the 20 m Fondation PlanetSolar dome has a dual pressure system and emergency power.
When should you choose helium, and which rules apply?
Helium is for objects that must float above an audience or a street; then the gas price, wind on the tethers and the rules for captive balloons all come into play.
In Switzerland, the OACS ordinance bans flying a captive balloon of up to 40 m³ within 3 km of the runways of a civil or military aerodrome, unless air traffic control or the aerodrome manager grants an exception.
The operator also needs liability insurance of at least 1 million francs, except for a captive balloon with a payload under 0.5 kg and a volume under 30 m³.
In the United States, 14 CFR Part 101 covers moored balloons more than 6 feet in diameter or holding more than 115 cubic feet of gas, which may not fly within 5 miles of an airport boundary or more than 500 feet above the surface. Local rules are to be checked with the city or the venue.
The guide to inflatable projection spheres covers the same choice for a sphere that hangs, stands or floats.
Full specifications
| Buttonscarves giant bag | constant air and sealed air, fully lit |
|---|---|
| Haut-Bugey Agglomération sealed totems | inflated with a small 12 V pump, no 220 V socket |
| Mosaert cloud | 6 m, filled with helium |
| Fondation PlanetSolar dome | dual pressure system, emergency power |
| Helium lift | 1.02 kg per cubic metre, envelope included |
| Captive balloon in Switzerland | up to 40 m³: not within 3 km of the runways of an aerodrome |
Frequently asked questions
Do inflatables need to stay plugged in?
Yes if they are constant-air, because the blower makes up for lost air. A sealed-air inflatable is inflated and then unplugged, like the Haut-Bugey Agglomération totems, inflated with a small 12 V pump.
How much electricity does an inflatable blower use?
For the WAY agency moons, Digital Inflatables specifies only 120 watts; a larger structure needs a more powerful blower.
What happens to a constant-air inflatable in a power cut?
It slowly deflates. For a large volume open to the public, emergency power takes over, as on the Fondation PlanetSolar dome.
How much does a cubic metre of helium lift?
1.02 kg, envelope included, so less is left for the object and its fittings.
Where are helium captive balloons banned in Switzerland?
Within 3 km of the runways of a civil or military aerodrome, for a captive balloon of up to 40 m³, unless air traffic control or the aerodrome manager grants an exception.
Sources
- Fedlex, ordinance on special category aircraft fedlex.admin.ch
- Cornell, moored balloon rules law.cornell.edu
- UCSB Physics, helium lift web.physics.ucsb.edu
- USGS, helium pubs.usgs.gov
- HSE, inflatable play equipment hse.gov.uk
- Town of Pont-Audemer, call for projects ville-pont-audemer.fr
- gr.ch, inflatable arch gr.ch
- Digital Inflatables Instagram post instagram.com
- Digital Inflatables projects page digital-inflatables.com
Drafted with AI assistance from the company’s verified facts, reviewed and approved by Jodoc Elmiger, founder and managing director of Digital Inflatables.
