Filling with Helium
Foil balloons last for 3 to 5 days and are refillable.
Latex balloons filled with helium typically float for only 6 to 12 hours. The gas escapes through small pores in the latex. Treated with a product called Hi-Float – a glue like gel that makes the latex less porous and helps lock the helium in, they will last for over a week. If using in our metallic confetti balloons, remove the confetti first, fill with Hi-Float first and rub. Can't be used with tissue paper confetti as it wettens the paper.
Helium gas is sensitive to extreme temperature changes. This means that:
Helium balloons might appear deflated in cold air – to resolve the problem, simply put your balloon somewhere warm and it will expand again
You need to remember to keep your balloon away from extreme heat however, as this could cause the helium to expand and the balloon to burst.