Teton Altos -18°C/0°F sleeping bag review: affordable comfort for cold UK nights
We took the Teton Altos -18°C/0°F out for back-to-back nights in Snowdonia to see if this budget-friendly down bag could really handle British wild camps. Here’s everything you need to know.
Teton Altos -18°C/0°F sleeping bag
Ideal for: Backpacking, 4-season wildcamping
Not suitable for: Fastpacking, summer camping
The Teton Altos -18°C/0°F is a down-filled mummy sleeping bag designed for sub-zero UK wild camps and budget-conscious backpackers. At just under £226, it’s one of the most affordable options in its class. While its weight (1.574 kg) makes this bag better suited to general camping than ultralight missions, it still compresses down nicely and has standout features like an excellent draught collar, anti-snag zipper and wide shoulder cut. It kept us warm in Snowdonia with temperatures hovering around 4°C and we wouldn’t hesitate to use it again.
The Good
Amazing warmth for the price
Very lofty
Roomy and comfortable
Very smooth zips
Comes with internal pocket
The Bad
Down quality and sourcing is a mystery
Hood is too tight for a pillow
Teton Altos -18°C/0°F sleeping bag review
Teton is a Utah-based outdoor brand best known for making functional kit at a wallet-friendly price point. They’ve built a reputation across the pond for creating gear 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. For anyone after a proper Teton sleeping bag review, we think this one deserves a close look.
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 Thermarest’s Parsec 0F offer better down with verified fill power and RDS certification, but both are substantially more expensive — and realistically sit well outside the bounds of what most casual, infrequent 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 the Teton Altos -18°C/0°F down sleeping bag
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 outing 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 Altos pad on this trip, and it 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 didn’t need to wear any extra layers, didn’t 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 — and a strong first impression of what this bag can do in real British weather.
A closer look at the Teton Sports -18C/0F sleeping bag’s comfort and features
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 doesn’t 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.
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 didn’t snag once, even when operating it half-asleep in the dark. That’s 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’s a small internal zipped pocket for keeping a phone or headtorch 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 didn’t run into damp issues on either trip, but with this sort of protection, you’re less likely to wake up to a soggy bag.
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The hood is the one area we found slightly lacking. It’s perfectly adequate for warmth, but its snug dimensions mean it doesn’t accommodate a pillow — something we usually tuck inside for support. Not a dealbreaker, but worth knowing if you rely on one for neck comfort.
Lastly, you’ll 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 also back the Altos with a lifetime warranty, which adds a reassuring bit of longevity to what is already a well-constructed bit of kit.
While we still wish there were more transparency around the fill quality, there’s no denying the Altos -18°C/0°F is a very capable budget down sleeping bag that’s been smartly built for real-world use.
Field performance in the British cold
Warmth-wise, the Altos -18°C/0°F held up well on both Snowdonia wild camps. We didn’t need to layer up inside it and never felt the chill, even with the zip partly undone. Granted, we haven’t 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’s not ultralight material, but it’s more than packable enough for backpackers who are happy to carry a little extra for more warmth. 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.
Teton Altos -18°C/0°F sleeping bag FAQs
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The Teton Altos -18°C/0°F is rated to 0°F (–18°C), making it a true winter bag on paper. While exact EN/ISO comfort ratings aren’t listed, field testing suggests it’s well suited to UK cold weather conditions down to below freezing, with the potential to go lower with appropriate layering.
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We used the Altos -18°C/0°F on two separate wild camps in Snowdonia with overnight temperatures hovering around freezing. It kept us warm and comfortable both times, even without thermals or extra layers. While we haven’t tested this bag in sub-zero British conditions yet, it’s showing plenty of potential.
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Yes, while not ultralight, the Altos -18°C/0°F packs down to about the size of a football using the included compression sack. At 1.574 kg, it’s heavier than some premium bags, but still very manageable for winter wild camps and general backpacking.
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Absolutely. For around £226, you get a roomy, warm, and well-made down sleeping bag with premium features like a draught collar, snag-free zip and internal pocket. The only trade-off is the unknown quality of the down fill — but otherwise, it’s outstanding value for money as a reliable budget down sleeping bag.
The Teton Altos -18 sleeping bag: Our final verdict
If you’re after a reliable source of warmth for British winter wild camps — and don’t want to fork out over £300 — the Teton Altos -18°C/0°F should absolutely be on your radar. What really stands out here is how consistently warm and comfortable this bag feels, even when conditions are damp and hovering just above freezing. Add to that the generous cut, practical features, solid packability and sensible price tag, and you’ve got one of the best value cold-weather bags we’ve tested. Yes, it’d 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.
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