Rechargeable hand warmers, ranked on the hours each one publishes

Who each of these is for, and who should skip them all

• Most skiers: the Ocoopa UT2s. Two warmers in one purchase, a published 5,000 mAh each and over 8 hours on low. One half per glove is the entire argument.
• Anyone buying this as a gift: the Zippo HeatBank 6. It is the only one with a published warranty, and a gift that fails in year two with no warranty is a bad gift.
• A child’s mitten or a stocking: the UT5 Nano. Smaller than a palm, published to 125F, under twenty dollars - and carrying the skip note below, because no run time is published.
• Skip all three if your hands are cold because your gloves are wet. A warmer in a soaked glove warms water. The five fixes for cold hands, in the order they work is the page to read first, and four of the five cost nothing.
• Skip them for a once-a-year trip. A box of disposables costs less than one rechargeable, works straight out of the packet and does not need charging in a hotel room.

What this page ranks on

• 1. Published run time, with the setting it is quoted at. The only figure that answers the question anyone actually has, which is whether it lasts until the last lift. Every run time on this page is quoted on LOW, because that is how the makers quote them.
• 2. Published battery capacity. A cross-check on the run time. A warmer publishing hours but no capacity is a warmer whose hours cannot be sanity checked.
• 3. One warmer or two. You have two hands. A single unit warms one pocket at a time, which is why the split pair wins here.
• 4. Published maximum temperature. Useful, but less than it looks: the top setting is also the setting that empties the battery fastest.
• 5. A published warranty term. This is a lithium battery that lives in a cold pocket. Exactly one of these publishes a term.
• Not “heats in 3 seconds”. Every warmer in this category heats quickly. None of them stays hot for as long as it heats fast.

The three rechargeables, and the disposable they are competing with

Read the last column before the first three. A disposable sachet publishes a longer run time than any battery here, weighs almost nothing, costs about a dollar a pair and cannot go flat on the drive up. What it cannot do is come back tomorrow - and over a season of weekends, that is the whole case for a rechargeable.

The break-even, which is simpler than it looks

A rechargeable only makes financial sense if you ski enough days to use more disposables than it costs. At roughly a dollar a pair, the 39.99 Ocoopa pays for itself somewhere around 40 days of hand warmers - several seasons for a once-a-year family, one winter for a commuter who also uses them off the mountain.

Which is why the real argument for a rechargeable is not money. It is that you always have one: no box to remember, no sachet left in a jacket since last March, no shop at the base charging four dollars a pair. A warmer on a charger by the door is a warmer that comes with you.

The picks

Ocoopa UT2s MagTwins

The pick, and the only one here that answers the two questions that matter at once. Ocoopa publishes 5,000 mAh per half and over 8 hours of heat on low from each half, across four temperature levels up to 136F.

The split is the feature. It is one object in the shop and two warmers on the mountain: a magnetic pair that comes apart, published as 270 degrees of heating surface with the remaining 90 degrees holding the halves together. Every other single-unit warmer in this category warms one hand while the other one waits, which is not how cold hands work.

It also charges a phone - Ocoopa publishes 1.5+ phone charges from one half - and on a cold day a phone at 12 percent is a more urgent problem than a cold thumb. Why cold kills a phone battery, and where to carry it.

Honest cons. No warranty term is published on the product page, which on a lithium cell is the gap that matters. The published hours are on the LOW setting; the top level will not see out a full day. A joined pair separates easily, which is the point and also how one half ends up under a chairlift. And it is the dearest here at a published $39.99.

Zippo HeatBank 6

The one to buy as a gift, because it is the only one with a published 1-year warranty. Zippo publishes a 4,400 mAh battery, up to 6 hours of run time, three heat settings and dual-sided heat up to 120F (50C) - plus battery and heat indicator lights, a neck lanyard, and full dimensions at 4.25 x 1.73 x 0.95 inches and 0.31 lb.

Dual-sided matters more than it sounds. A warmer that heats one face only has to be held the right way round in a glove, by a hand that is already too cold to care. This one does not.

It is also a USB power bank, which is the second-best reason to own it. Zippo publishes charging for phones, cameras and similar - so it earns its pocket space on days nobody’s hands are cold at all.

Honest cons. One unit, one hand: at 6 hours and $34.95 published, two hands means two purchases and $70. 120F is the lowest published top temperature here. Six hours is a half day of skiing, less on the top setting. And it is a long thin brick rather than a palm-shaped one, which suits a jacket pocket better than a glove.

Ocoopa UT5 Nano, and why it carries the skip

The cheapest rechargeable pair here, published as smaller than a palm and heating to 125F (52C) in seconds with intelligent thermal control. At under twenty dollars for two, it is the obvious stocking filler in this category - and the only one of these that genuinely fits inside a child’s mitten rather than beside it.

It carries the skip because Ocoopa publishes no run time and no battery capacity for it at all. On a page that ranks on published hours, a product with no published hours cannot be the pick, and a smaller body holding a smaller battery is a shorter day whatever the unpublished number turns out to be.

Buy it knowing that. For a cold walk to school, a chairlift pocket or a stocking it is a good purchase at the price. For a full day on a mountain, buy the UT2s and accept the extra twenty dollars.

HotHands disposables, which still beat all three on hours

Included deliberately, because a roundup of rechargeables that pretends disposables do not exist is an advertisement. HotHands publishes up to 10 hours on the standard pair - longer than anything with a battery on this page - and they weigh nothing, cost about a dollar and work the moment the packet opens.

What they cannot do is come back tomorrow, and they cannot be charged in a hotel room at eleven at night. If you ski once a year, buy a box of these instead of anything above. The disposable warmers page compares the sizes and run times, including the Super Warmer at up to 18 hours and the insole and toe shapes.

Using one properly, which is most of the result

• Charge it the night before, every time. A rechargeable warmer fails in exactly one way: nobody charged it. Keep it on the charger by the door with the ski bag.
• Start it before your hands are cold. A warmer heats a glove, not a hand. Warming a hand that has already gone white takes far longer than keeping a warm one warm.
• Use the low setting. Every published run time on this page is a low-setting figure. High is for the chairlift, not the whole day.
• Keep it out of the snow. Nothing here publishes a waterproof rating - no IP figure at all - so treat all three as pocket electronics.
• Store it part charged over summer. Lithium cells left flat for six months in a garage come back weaker, and there is no warranty on two of these.

Fix these first, because a warmer is the second thing to try

Cold hands are usually a symptom. Before spending forty dollars on a battery, work through the free causes:

• A wet glove. The commonest cause by a distance, and no warmer fixes it. A dry spare pair in the pack is the real answer - and drying them properly overnight is what stops it happening twice.
• A glove that is too tight. Compression stops circulation and a warmer cannot push blood through a squeezed hand. The sizing page covers the test.
• A cold core. Your body closes down the fingers to protect the middle. A warmer mid layer frequently fixes warm hands - which layer, and how thick.
• The wrong format. A mitten is warmer than a glove at the same insulation, and it has room for a warmer as well. The mittens roundup covers that, and the comparison covers the choice.
• A thin liner. Cheaper than any warmer and it works every day rather than when charged - the glove liners roundup.