Wild CampingTeton SportsSleeping Bag

Teton Altos –18°C/0°F sleeping bag review: affordable comfort for cold UK nights

A roomy, warm and budget-friendly winter sleeping bag with smart features and solid cold-weather performance.

✓  RecommendedTeton Altos –18°C/0°F Weight1.574 kgLimit rating–18°C/0°FPrice~£226 The good✓  Amazing warmth for the price
✓  Very lofty — expands fast and evenly
✓  Roomy and comfortable cut
✓  Very smooth anti-snag zip
✓  Internal zipped pocket
✓  Draught collar and zip baffle
✓  Water-resistant shell
✓  Lifetime warranty
The not-so-good✗  Down quality and sourcing unclear
✗  Hood too snug for a pillow
Check price on Amazon →

At a glance

Overview

Teton is a Utah-based outdoor brand best known for making functional kit at a wallet-friendly price point. They have built a reputation across the pond for creating kit that performs far better than the price tag suggests, particularly for campers and budget-conscious adventurers. While not a household name in the UK yet, products like the Teton Altos range are starting to turn a few heads here — especially among those searching for a budget down sleeping bag that delivers real-world performance.

The Teton Altos –18°C/0°F down sleeping bag is their cold-weather mummy bag, built to keep you warm down to 0°F (–18°C). That makes it ideal for UK winter wild camps, bivvies and backpacking in the colder months. It comes in at a claimed 1.564 kg (our scales said 1.574 kg) and compresses to about the size of a football. It retails at £226 at time of writing, which puts it well below competitors with similar temperature ratings.

To put that in context: Mountain Equipment’s Glacier 300 is lighter (890 g) and uses 700-fill ethically sourced down, but costs £350. Sierra Designs’ Nitro 0 and Therm-a-Rest’s Parsec 0F offer better down with verified fill power and RDS certification, but both sit well outside what most casual or beginner campers are willing to spend. That makes the Altos –18°C/0°F one of the best-priced down sleeping bags on the market right now — and it does a lot for the money.

How we tested

We tested the Teton Altos –18°C/0°F over the course of two separate wild camps in Snowdonia, each offering a slightly different challenge. The first took us to a sheltered valley just beneath the Glyderau range. The wind was low, the air was damp, and the overnight temperature dropped to around freezing. We paired the Altos with the matching Teton pad on this trip, which gave us a fair sense of how the sleeping bag performs in cool and clammy conditions. Despite the chill, the bag lofted quickly and retained heat well through the night.

The second trip involved a higher camp near the summit of Moel Siabod, pitched just below a rocky outcrop with minimal protection from the elements. Winds were more noticeable here, and with clear skies the temperature dropped to around 2°C. This time we used the Therm-a-Rest NeoAir XTherm underneath, which helped maximise insulation from the ground. We did not need to wear any extra layers, did not cinch the draught collar tight, and still stayed warm and comfortable all night long. Between the roomy cut and steady warmth, it made for two genuinely restful nights under canvas.

Features and performance

Comfort, fit and loft

One of the first things we noticed pulling the Altos out of its sack was the generous shape. At 5′9″ ourselves, we had room to spare — not just in terms of length, but across the shoulders too. For anyone tall, broad or prone to tossing and turning through the night, this extra space is a real plus. It does not taper too aggressively, which makes it feel more forgiving than the usual straightjacket-style mummy cut. You can shift position without waking yourself up or getting tangled in fabric.

Once unstuffed, the bag lofts up beautifully. It expands fast and evenly, giving you a reassuring sense of insulation straight away. We did spot a few loose feathers on first use — nothing major, and not something that worsened across both nights we tested. Still, something to keep an eye on long term.

Zip, draught collar and features

Zipping in for the night, you really start to appreciate some of the bag’s smarter design details. The two-way zip glides smoothly from top to bottom and did not snag once, even when operating it half-asleep in the dark. That is not something we can say for many bags, regardless of budget. Alongside the zip runs a chunky down-filled baffle, which works exactly as it should — sealing in warmth and preventing cold spots. Further up, a draught collar wraps softly but snugly around the neck, offering another line of defence when the temperature drops.

Storage is nicely thought through too. There is a small internal zipped pocket for keeping a phone or head torch battery warm overnight — an essential touch for UK winters. The water-resistant shell fabric is another confidence booster, especially when camping in condensation-prone corners of the country. We did not run into damp issues on either trip, but with this sort of protection, you are less likely to wake up to a soggy bag.

The hood is the one area we found slightly lacking. It is perfectly adequate for warmth, but its snug dimensions mean it does not accommodate a pillow — something we usually tuck inside for support. Not a dealbreaker, but worth knowing if you rely on one for neck comfort.

You will also find three hanging loops stitched into the foot of the bag — a simple but genuinely useful addition for drying it out at home or in a bothy. Teton back the Altos with a lifetime warranty, which adds a reassuring bit of longevity to what is already a well-constructed bit of kit.

“For the weight, warmth and features you get at this price point, it’s really hard to complain. As a budget down sleeping bag, this one punches well above its weight.”

Field performance in the British cold

Warmth-wise, the Altos –18°C/0°F held up well on both Snowdonia wild camps. We did not need to layer up inside it and never felt the chill, even with the zip partly undone. Granted, we have not tested it in proper sub-zero conditions yet, but based on its loft, cut and thermal features, we think it would hold its own through a typical British winter.

We also appreciated how well this bag packed down. At around the size of a football, it is not ultralight material, but it is more than packable enough for backpackers who are happy to carry a little extra for more warmth. While we still wish there were more transparency around the fill quality, there is no denying the Altos –18°C/0°F is a very capable budget down sleeping bag that has been smartly built for real-world use.

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Our verdictOne of the best-value cold-weather sleeping bags we’ve tested.If you are after a reliable source of warmth for British winter wild camps and do not want to fork out over £300, the Teton Altos –18°C/0°F should absolutely be on your radar. What really stands out is how consistently warm and comfortable this bag feels, even when conditions are damp and hovering just above freezing. Add the generous cut, practical features, solid packability and sensible price tag, and you have got one of the best-value cold-weather bags we have tested.Yes, it would be great to have more clarity on the down fill. But for most UK-based adventurers looking for a dependable budget down sleeping bag, this one hits the mark.Check price on Amazon →

FAQs

What are the Teton Altos –18°C/0°F sleeping bag’s temperature ratings?Rated to 0°F (–18°C), making it a true winter bag on paper. Exact EN/ISO comfort ratings are not listed, but field testing suggests it handles UK cold weather down to below freezing well, with more to give when layered up.

How warm is the Teton Altos –18°C/0°F in real-world conditions?We used it on two wild camps in Snowdonia with overnight temperatures hovering around freezing. It kept us warm and comfortable both times, without thermals or extra layers. While we have not tested it in sub-zero British conditions yet, it is showing plenty of potential.

Is the Teton Altos –18°C/0°F easy to carry in a backpack?Yes. While not ultralight at 1.574 kg, it packs down to about the size of a football using the included compression sack — manageable for winter wild camps and general backpacking.

Is the Teton Altos –18°C/0°F worth the money?Absolutely. For around £226, you get a roomy, warm, well-made down sleeping bag with a draught collar, snag-free zip, internal pocket and lifetime warranty. The only trade-off is the unknown quality of the down fill — but otherwise, outstanding value for money.