When to replace a ski helmet, and how to look after the one you have

Why one crash ends a helmet

Understanding this makes every other rule on the page obvious. A ski helmet is a hard outer shell over a thick layer of expanded polystyrene foam, and the foam is the part that protects you. In an impact it crushes, and in crushing it absorbs energy over a longer time than your skull would, which is what reduces the force reaching your head.

Crushing is permanent. The foam does not decompress and re-set the way a mattress does; it is designed to be sacrificed once, and it has done its job by being ruined. The awkward part is that the crushed region can be entirely invisible under an undamaged shell. A helmet can look brand new and have nothing left in the area that matters.

When to replace, in order of certainty

The five-year question, honestly

Five years is the figure most helmet makers give, and it is worth being precise about what it is and is not. It is not a certification requirement and it is not a hard expiry date derived from published test data. It reflects a combination of real ageing — ultraviolet exposure, sweat, temperature cycling and the slow compression of the comfort padding — and the fact that safety design moves on over five years.

Our reading: treat it as a strong prompt rather than a deadline. A helmet stored properly, worn five days a year, with intact padding and a working fit system, is not dangerous on its sixth birthday. A helmet left in a car every summer for four years might well be worse than one that is seven and lived in a closet. What changes the answer far more decisively is any impact at all.

Cleaning without destroying the foam

1. Take out the pads and ear pads if they come out. Most modern helmets have removable liners specifically so they can be washed.
2. Hand wash the pads in cool water with mild soap. Rinse thoroughly, squeeze rather than wring, dry flat at room temperature.
3. Wipe the shell and the foam with a damp cloth and mild soap only. Nothing else.
4. Air dry completely before reassembling. A helmet reassembled damp is a helmet that smells by December.

Three things to keep away from it entirely: solvents and alcohol-based cleaners, which attack both the shell and the foam and can degrade them invisibly; a dishwasher or washing machine, for the whole helmet; and heat of any kind for drying. Room temperature and time.

Storage, which is where most damage happens

A helmet spends most of its life not being worn, and heat is its enemy. The inside of a car in July is the single worst place you can put one, and it is also the place most helmets end up. Attic storage is nearly as bad.

• Store it dry, in an interior closet, out of direct sunlight.
• Do not stack heavy things on it. Sustained pressure on foam is not what it is designed for.
• Keep the goggles out of the helmet during storage: the strap can compress the liner and the lens gets pressed against the shell. The full summer storage list is here.
• Do not store it with stickers you did not check. Adhesives and solvents in some stickers can attack the shell, which sounds like a myth and is a real maker warning.

What makers actually publish

Warranty terms differ more than most people expect and they are published, so they are worth reading before you buy rather than after something breaks. Across the picks on this site the published spread runs from no stated term at all up to three years, and a warranty covers manufacturing defects rather than crash damage in every case we have read.

Crash replacement is a separate thing: a program where the maker offers a discounted replacement after a documented impact. It is a genuinely valuable feature and none of the helmets we currently list publishes one, which is exactly why it is recorded on every product row as “no published crash replacement” rather than left blank. If a maker adds one, that row and its score change. How the warranty axis is scored is published in full.

Fit changes, and that is a replacement trigger too

The comfort padding inside a helmet compresses with use. After several seasons a helmet that fit snugly can have a few millimeters of extra room, and a helmet that moves is a helmet doing less than it should. Re-run the fit test at the start of each season rather than assuming last year’s answer:

1. Put it on with the chin strap undone.
2. Shake your head firmly side to side and nod.
3. The helmet should move your scalp rather than sliding over it. If it slides, it is too loose.
4. Then check the goggle gap: no exposed forehead between the goggle top and the helmet brow. The gap problem is covered properly here.

If the dial cannot take up the slack any more, replace the pads if the maker sells them, and replace the helmet if not. The full sizing page covers measuring your head properly, which is where most badly fitting helmets started.

Children: growth, not age, is the trigger

A child’s helmet is usually outgrown long before it is worn out, and that is a much more frequent replacement driver than any five-year rule. Measure the head at the start of every season, and do not solve growth by buying two sizes up: a loose helmet is doing a fraction of its job.

Passing a helmet down between siblings is fine if you know its full history — no impacts, stored properly, padding intact, and it still fits the younger child snugly. That is a different situation from buying a stranger’s helmet at a swap, where you know none of those things. Where hand-me-downs work and where they do not goes through this item by item, and the kids size chart by head circumference is the measurement half.