Highlander Serenity 450 Mummy Sleeping Bag: a great value, 4-season synthetic bag

A wonderfully warm cocoon for winter camping adventures, the Serenity 450 is a quality sleeping bag at an unbeatable price

Highlander Serenity 450 Mummy Sleeping Bag: wild camp
(Image: © Alex Foxfield)

Advnture Verdict

A great value synthetic bag that is well equipped for winter camping. Wonderfully insulated and capable even when wet, it will keep you warm even when it’s just beyond freezing outside. Its size and weight make it less appealing than a premium down bag for sustained backpacking, but for single night wild camping or year-round car camping, it’s a solid option.


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    Suitable for winter camping

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    Retains thermal qualities when wet

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    Cozy, snug and warm

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    Internal security pocket

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    Great value


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    Large packed size

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Highlander is a Scottish brand that makes high performing yet affordable products for the mountains. Its testing ground, the wilds of the Scottish Highlands, can be a brutal place in winter, demanding respect from those who venture into their icy embrace. It is not a place for sub-standard gear.

Its Serenity 450 bag is a great value synthetic mummy bag that’s warm enough to take up into the hills during the shoulder seasons and even into winter. I ventured out on wild camping trips in Wales’ Brecon Beacons National Park during late fall to put its toastiness to the test.

Highlander Serenity 450 Mummy Sleeping Bag: product photo

I ventured out on wild camping trips in Wales’ Brecon Beacons National Park during late fall to put its toastiness to the test (Image credit: Highlander)

Highlander Serenity 450 Sleeping Bag: first Impressions

Immediately obvious is the rather large pack size. Heavily insulated winter bags are naturally larger than their 2- or 3-season counterparts and synthetic insulation is less compressible than down, so takes up more space. However, the stuff sack features four compression straps to make things as compact as possible.

As well as being less compressible, polyester doesn’t share down’s magical warmth to weight ratio, so you need more of it to achieve a winter-ready sleeping bag. This means synthetic bags are usually heavier, which is certainly true of the Serenity’s 2kg (70.5 oz), almost twice as heavy as some down winter bags. It got me wondering how practical it would be for a wild camping trip.

Despite all of this, the Serenity does have the advantage of being only a fraction of the price of a premium down bag, so it’s perhaps more prudent to put it in the ring with other synthetic winter bags. In such a bout, the Serenity holds its own in terms of weight and pack size.

Highlander Serenity 450 Mummy Sleeping Bag: stuff sack

The stuff sack features four compression straps to make things as compact as possible (Image credit: Alex Foxfield)

Enough about what’s on the surface, let’s get inside. It’s certainly a cozy bag but perhaps not quite as plush feeling as some winter bags. However, it only takes a minute or two to get that lovely sensation that its loft is holding onto your heat. The mummy shape helps to make it feel delightfully snug; you get the sense that there’s no wasted space.


List price: £80 (UK)
Style: Mummy
Weight: 2kg / 70.5oz
Length: 220cm / 86.6in
Pack size: 41 x 26 x 26cm / 16 x 10 x 10in
Max user height: 171cm / 5ft 7in
Fill: 450gsm SFX spiral polyester hollowfibre
Comfort: -4°C / 24.8°F
Limit: -10°C / 14°F
Best for: Winter camping and wild camping all year round


The 450 in its name corresponds to the grams per square meter (gsm) of its spiral polyester hollowfibre insulation. This is the highest loft in Highlander’s range of sleeping bags, though their more expensive Echo 400 and Echo 350 bags are even warmer. Nevertheless, with a comfort rating of -4°C (24.8°F), the Serenity has what it takes to cope with those cold summit wild camps. The shell and lining are also made from polyester.

An advantage of the insulation used here is that it still holds onto its warmth when wet, so even if you have a condensation nightmare, at least you’ll still be warm. If you do get it a little wet while you’re out there, there are two fabric loops at on the bottom of the bag, so you can hang it out to dry in front of a bothy’s roaring fire – or perhaps somewhere less obviously romantic, like on the drying rack when you get home.

Highlander Serenity 450 Mummy Sleeping Bag: bag laid out

The Serenity holds onto its warmth even when wet (Image credit: Alex Foxfield)

The full length two-way zip is accompanied by an insulated side baffle to keep the warmth in. There are draw cords on both the hood and the shoulder baffle, so things can be tightened up if things get truly Baltic. Also on the inside by your chest is an internal security pocket, which is fastened by a Velcro tab. This is useful for items like a phone or headlamp (see our guide to the best headlamps for some good options).

In the field

First off, let’s revisit the weight and pack size and the bag's suitability for wild camping. I opted to take the Serenity out in a large 65-liter backpack and it took up the whole bottom third of the pack. This just left enough room for my tent and other winter camping essentials, and I was comfortable on the trails as I made for my designated wild camping spot.

Nevertheless, I wouldn’t want to tackle technical terrain for days on end with such a load. So, I’d say the Serenity is a great option for a one-night winter wild camp but not something you’d want to haul over multiple summits on a three-day expedition. Leave that to the lightweight down bag crew. However, you could probably bring it along for on a long-distance trail, provided the gradients and elevation change weren't too stark.

Highlander Serenity 450 Mummy Sleeping Bag: wild camp shot

It's warm enough to sit out in when morning comes around (Image credit: Alex Foxfield)

Access and egress have been well thought through. The stuff sack’s compression straps and buckle are all oversized, which makes them easy to manipulate, tighten and loosen when wearing your best hiking gloves. Likewise, the bag’s two-way reversible zippers feature large pull tabs too, so it was always easy to open and close it up and the zips are also snag proof. If I was ever feeling too warm, I could unzip a little to regulate the temperature inside.

Come the night, I was as comfortable as can be expected on wild camping trips. I experienced one morning that was almost frosty, my phone reliably informing me that it was 6°C in the valley, so it must have been close to freezing up high. In the bag, I wouldn’t have known necessarily, as I was happily cozy and warm, my misting breath the main hint that things were somewhat chillier on the outside. At the end of the day, that’s all you can ask for in a sleeping bag.

Alex Foxfield

Alex is a freelance adventure writer and mountain leader with an insatiable passion for the mountains. A Cumbrian born and bred, his native English Lake District has a special place in his heart, though he is at least equally happy in North Wales, the Scottish Highlands or the European Alps. Through his hiking, mountaineering, climbing and trail running adventures, Alex aims to inspire others to get outdoors. He's the former President of the London Mountaineering Club, is training to become a winter mountain leader, looking to finally finish bagging all the Wainwright fells of the Lake District and is always keen to head to the 4,000-meter peaks of the Alps. www.alexfoxfield.com