Men's sizes

Top

Pants

Women's sizes

Top

Pants

Close to the body, not tight.

The heat works best when the panels sit against you. So both pieces are cut close, with enough stretch to stay comfortable all day. These are body measurements. Measure yourself, not your clothes. Allow ±0.5–0.75" (1–2 cm).

1. Measure your chest. Stand relaxed. Wrap a soft tape under your arms, around the fullest part of your chest. Keep it level across your shoulder blades. Snug, not tight.
2. Measure your sleeve. Bend your arm slightly. Measure from the centre back of your neck, over your shoulder, down the outside of your arm to your wrist.
3. Measure your hips and waist. For hips, stand with your feet together and measure around the fullest part of your hips and seat. For waist, measure around your natural waist, just above your hips, without pulling the tape tight.
4. Pick your sizes. Choose the top by your chest and the pants by your hips. Wearing them under jackets and trousers? Stay true to size. Wearing them over thick clothing? Size up. We've updated our size labels based on customer feedback. If you've ordered before, check the charts again. Your size may have changed.

Between sizes or an athletic build? Size up. Because the fit is close, the next size won't feel baggy. For the pants, the elastic waist will adjust, but the hip won't. Still not sure? Email us your measurements and we'll tell you which sizes to get. And if they don't fit, our 60-Day Fit Guarantee covers free size exchanges.

Head-to-toe warmth, without the bulk.

Icy commutes. Long shifts outside. Freezing stands and chairlifts. Stacking thick layers keeps some of the cold out, but you end up bulky, stiff and still cold somewhere. The HearthLayer set puts heat against your whole body, under whatever you already wear.

• Warm in 30 seconds. 28 ThermoSphere™ heat panels in total. 16 in the top cover your core, elbows and back. 12 in the pants cover your waist, hips, thighs and calves.
• Top and pants, controlled separately. Each piece has its own button and power bank. Run your top on High and your pants on Low, or the other way round.
• All day on one charge. Up to 12 hours on Low. Two 10,000 mAh power banks are included, one for each piece.
• No bulk. The panels are ultra-thin, flexible carbon, built into stretch fabric. No stiff wires. Both pieces slip under coats, workwear and snow gear without bunching.

Where it works best: commuting, outdoor work, early walks, spectating, camping, motorcycling, skiing, and staying warm at home without turning up the heating. During hard runs or intense training, most people heat up fast. Use Low or switch off while active, then turn it up on breaks.

Try it for 60 days. If it's not for you, our 60-Day Money-Back Guarantee has you covered.

Built to stay safe. Both pieces run on 5V USB — the same voltage as charging your phone. Built-in sensors keep the heat steady and adjust it automatically if it gets too hot. FCC certified.

What is it made of?

• Soft stretch polyester — a close-to-body fit that moves with you
• 28 ThermoSphere™ carbon panels — ultra-thin and flexible, 16 in the top and 12 in the pants
• Sealed, insulated heating elements and wiring — so the electronics survive the washing machine
• Internal power bank pockets — low-profile, at the hem of the top and the waistband of the pants, with short routed cables

How do I wash it?

• Take both power banks out first. Unplug them and remove them from the pockets every time.
• Machine wash cold. Zip up the pockets, put both pieces in a laundry bag, and use a gentle cycle.
• Line dry only. No tumble dryer.
• Skip the harsh stuff. No bleach, no ironing, no dry cleaning. They can damage the heating panels.

What's in the box

• 1 HearthLayer™ Heated Baselayer Top with 16 ThermoSphere™ panels
• 1 pair of HearthLayer™ Heated Baselayer Pants with 12 ThermoSphere™ panels
• 2 10,000 mAh power banks (one for each piece, up to 12 hours of heat)
• 2 USB cables for charging your power banks

Wear it every day. Both pieces are machine washable, so you can treat them like any other base layers. Just remember: power banks out before they go in the wash.

Two power banks included, one for each piece.

Every set comes with two 10,000 mAh power banks, so the top and pants can run at the same time. That gives you up to 12 hours of heat on Low. Medium and High use more power, so the heat lasts a shorter time.

How to turn it on

1. Plug in the power banks. Connect one to the cable in the pocket at the hem of the top, and one in the pocket at the waistband of the pants.
2. Hold each button for 3 seconds. The light comes on and you feel the warmth within 30 seconds.
3. Press to change the level. Each press cycles through Low, Medium and High. The light colour shows your setting. The top and pants change separately.

Power

• 5V USB. Low voltage, no mains electricity, no exposed wiring.
• Works with any standard 5V USB power bank. Handy if you want spares for longer days.
• Automatic temperature control. Sensors watch the heat and adjust it so it never goes past your chosen level.

Charge them overnight. Plug both power banks in when you take the set off. They're ready for the whole day by morning.