Pick your size, then trim to fit.

Each size covers a range of shoe sizes. You cut them down to match your boot exactly. It takes about five minutes, and you only do it once.

1. Use your old insole as a template. Pull the insole out of the boot you'll wear them in. Lay it on top of the HearthFoot insole, heels lined up.
2. Trim along the guidelines. The cut lines are printed on the bottom. Cut to the line that matches your old insole, a little at a time. Only cut along the printed lines. The heating element sits in the forefoot, so never trim past the marked area.
3. Slide them in. Swap them in where your old insoles were. They should sit flat, with no bunching at the toe or heel.

Tight boots? The forefoot is about 5 mm thick and the heel about 8 mm. Always take your old insoles out first. Wearing both stacks up height and squeezes your toes, and tight toes get cold faster.

Cold feet end the day early. That is the whole problem.

You stamp your feet on the job site. You wear two pairs of socks and your boots get too tight. By lunch, your toes are numb. Thicker socks and foot warmers only get you so far. We built these around the three things that actually go wrong.

• Heat where the cold hits first. Your toes go numb before anything else. They're furthest from your heart, and they sit right on the cold ground. The carbon fiber heating runs across the whole forefoot — right under your toes and the ball of your foot.
• Change the heat without taking your boots off. Three settings: Low, Medium and High. Switch between them with the wireless remote from up to 15 m away. Start on High to warm up, drop to Low to save battery.
• Heat that lasts the whole shift. Up to 8+ hours on Low, from a battery built into each insole. No packs clipped to your ankles, no wires up your leg. Work boots, hiking boots, ski boots or everyday trainers.

Built to switch itself off. Overheat protection cuts the power if the insoles get too hot. Short-circuit protection is built in too.

What are they made of?

Three layers, from the top down:

• Breathable EVA foam — cushions your foot and lets moisture out
• Thermal insulation with carbon fiber heating — heats the forefoot and keeps the warmth in
• Non-slip base — stops the insole sliding around inside your boot

About 5 mm thick at the forefoot and 8 mm at the heel. Each insole weighs about 120 g.

Wet and snow

Rated IPX4, so they handle splashes, sweat and damp boots. They are not waterproof. Don't submerge them, and don't wear them in boots that are full of water.

How do I care for them?

• Turn them off first. Never clean them while they're switched on or charging.
• Wipe, don't wash. Use a damp cloth with a little mild soap. No washing machine, no soaking, no running water.
• Dry them slowly. Take them out of your boots and let them air dry at room temperature. Keep them away from radiators, heaters and boot dryers.
• Don't fold or crush them. Bending the forefoot hard can damage the heating element.

What's in the box

• 1 pair of HearthFoot™ Heated Insoles
• 1 wireless RF remote control
• 1 dual USB charging cable
• 1 user manual

Between seasons. Store them flat and dry, out of your boots. See the Battery & Remote tab for how to look after the batteries while they're stored.

One battery built into each insole.

Each insole has its own 2,000 mAh rechargeable lithium-polymer battery (3.7V). You get up to 8+ hours of heat on Low. Medium and High use more power, so the heat lasts a shorter time.

Charging

• About 3 hours to a full charge.
• USB-C, 5V/1A. The dual cable charges both insoles at once from one USB plug.
• 500+ charge cycles. That's several winters of daily use.

The remote

• Wireless RF — works from up to 15 m (50 ft) away.
• Press to cycle through Low, Medium and High. No need to reach your feet or take your boots off.

Battery care

Charge them fully before your first use. Putting them away for summer? Charge them to about half, then top them up every couple of months so the batteries stay healthy.

Charge them overnight. Plug them in when you take your boots off. They're full by morning and ready for the whole day.