How Long Do Mylar Balloons Last With Helium

How Long Do Mylar Balloons Last With Helium? Answered

Last Updated on April 23, 2024 by Kimberlee Johnson

Mylar balloons provide a fantastic addition to celebrate any occasion. Yet, have you pondered how long helium-filled mylar balloons last?

With that, let’s dive into the factors that affect the longevity of helium-filled mylar balloons and offer tips on how to make them last as long as possible. 

So, if you’re wondering how long your mylar balloons will last with helium, read on.

How Long Do Helium-Filled Mylar Balloons Last?

Unicorn helium mylar balloon

Helium-filled mylar balloons can last 3-5 days, depending on the environment, how the balloons are taken care of, and the amount of helium used to fill the balloons.

Sometimes, the helium will slowly leak out of the balloons, but the mylar material will prevent the balloons from deflating. 

Besides, the mylar material will help to protect the balloons from the elements, such as wind [1], rain, and extreme temperatures, which will help them to last longer. 

Regardless of the material benefits, you must keep the balloons away from sharp edges and other objects that can puncture the mylar material to extend the balloon’s life.

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What Causes Mylar Balloons to Deflate?

Mylar balloons are made of a special metalized film designed to retain helium and keep the shape of the balloon. 

Unfortunately, like all balloons, Mylar balloons will eventually begin to deflate over time. One of the reasons is that its material is not elastic and can tear easily if not handled properly. 

When a Mylar balloon is filled with air or helium, it can be expected to deflate over time as the air molecules escape through the plastic film. 

The rate of air loss depends on how thick the film is and how well it seals, as well as the temperature and humidity of the environment. 

Plus, when a Mylar balloon is exposed to sunlight, the ultraviolet rays can cause the plastic film to degrade, leading to loss of helium and eventual deflation. 

How Can Mylar Balloons Be Prevented From Deflating?

Storing mylar balloons in a climate-controlled room away from direct sunlight and sharp objects is essential to prevent mylar balloons from deflating. 

Aside from that, it’s essential to check the helium level regularly and fill the balloons as necessary. 

You should also avoid tying mylar balloons to objects or surfaces that could puncture the balloons, such as sharp edges or branches.

In addition to proper storage, properly sealing mylar balloons can help prevent them from deflating. 

“A man should have duties outside of himself; without them, he is a mere balloon, inflated with thin egotism and drifting nowhere.”

Thomas Bailey Aldrich, American Writer

To do this, you should tie a knot at the end of the balloon and use a heat sealer to seal the knot. 

It keeps the helium from escaping, thus preventing the balloon from deflating. 

And when inflating the balloons, you should be careful not to overfill them and use the right amount of helium. 

Overfilled balloons can burst or deflate quickly, so you should be mindful of the amount of helium used.

Find out how you can keep the helium balloons from deflating here.

Is It Possible For Helium To Escape From Mylar Balloons?


Yes, helium can escape from mylar balloons. 

Mylar balloons’ thin, metallic film is not airtight; therefore, helium can escape through the tiny holes and gaps in the mylar material. 

While this occasionally happens due to flaws in the fabric, it more commonly happens at the balloon’s stem or the seams.

Hence, as the helium inside the balloon leaks out, the balloon will slowly deflate. 

The deflation rate depends on the size of the holes and the balloon size. Smaller balloons with larger holes will deflate faster than larger balloons with smaller holes.

Is It Okay To Fill Mylar Balloons With Just Air?

Yes, it is perfectly safe to fill mylar balloons with just air. Mylar balloons are made of a thin, flexible, metallic foil material that is both lightweight and durable. 

These balloons are designed to hold different types of gas, including helium and air. The mylar material is also non-toxic and safe for children and pets.

But how can you blow up foil balloons with helium?

Is It Safe To Leave Mylar Balloons In A Cold Car Overnight?

No, the mylar balloons won’t last as long if you leave them in the car overnight because the temperature will deteriorate them. 

Plus, the mylar material can become brittle in cold temperatures, which can cause the balloons to become weak and tear easily.

But to ensure the safety of the balloons, it is best to bring them inside when temperatures drop. 

If the balloons remain outside, tie them securely to a sturdy object so they cannot move or be blown away.


How should a Mylar balloon be properly disposed of?

Mylar balloons should be deflated by cutting them open to release the remaining helium or air and disposed of in the regular trash. 

Never release a Mylar balloon into the environment, as it can become a hazard to wildlife [2]. But what are other ways to properly dispose of helium balloons?

What kind of balloons work best in hot weather?

The so-called bubble balloons work best in hot weather because they are more durable and less likely to burst than other balloons.

The thick, elastic-plastic they’re made of means they won’t crack under stress or melt in the sun.

Which brand of balloons do experts use?

Experts typically use Qualatex latex balloons, the industry standard in professional balloon decorating.

Do helium balloons hold up better in the heat or the cold?

Helium balloons hold up better in cold weather, as the lower temperatures prevent the helium from expanding and dissipating quickly. 

Key Takeaways

Mylar balloons can provide a festive and fun atmosphere for any occasion. Proper care and maintenance allow these balloons to last for weeks when filled with helium. 

However, it is essential to remember that helium will eventually seep out of the balloons, so be sure to check the balloons periodically and refill them as needed. 

Plus, if you put in some extra effort, your mylar balloons will keep your celebration afloat for a long time. 


Kimberlee Johnson
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