Mountain Equipment
Mountain Equipment Helium 800 (Regular)
Best use
- Made for
- Backpacking and wild camping, Winter mountain
- Not for
- Bikepacking
Why these labels
- Backpacking and wild camping: The maker states this use, and the published specs do not rule it out.
- Winter mountain: The maker states this use, and the published specs do not rule it out.
- Bikepacking: Bulky for bike bags: packs to 17.9 litres
From the maker's stated use and the published specs.
- Summer wild camp: 5/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 7/10 UK hills in spring and autumn. Wind, rain, and nights near freezing.
- Winter camp: 8/10 UK winter or high ground. Below freezing, strong wind, possibly snow.
- Weight: 5/10 How much it adds to your pack, compared with the whole market.
Comfort -8 °C, limit -15 °C (ISO 23537).
Winter camps and high ground in the UK where the forecast is below -5 °C
- Comfort
- -8 °C
- Limit
- -15 °C
- Fill
- 700 fill down
- Weight
- 1.23 kg (Regular)
Packed size 17.9 L, 31 cm long and 24 cm across Compare with a 2-litre bottle
About as long as a 2-litre bottle and about two and a half times as wide. Drawn to scale.
Where to buy
Mountain Equipment £400 In stock. Free delivery.
View at shop: Mountain EquipmentUltralight Outdoor Gear £339.99 Out of stock. Regular size, 1 left when checked.
View at shop: Ultralight Outdoor GearPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Warmth
From maker's figures 10/10How cold a night you can sleep comfortably through. 10: The best you can buy for this.
Maker's comfort figure of -8 °C (limit -15 °C, extreme -36 °C) is colder than -5 °C. The maker names EN 13537/ISO 23537 but not the edition; its own 'Good Night's Sleep' figure of -16 °C is not used.
Room inside
Estimate: only 1 review about room inside (fewer than the 3 we need, so never above 8) 6/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 6: A bit better than average.
Only one German test says the current cut is somewhat roomier than before. No reviewer describes room for side sleepers. The maker gives a maximum inside width of 78 cm; the Helium GT 800 is the extra-wide option.
Weight
From maker's figures 5/10How much it adds to your pack. 5: Does the job. Average for wild-camping gear.
The maker's 1,230 g for the Regular sits in the 1,000–1,299 g band (one shop lists 1,215 g, same band).
Packed size
From maker's figures 1/10How much room it takes in your rucksack. 1: A real weak point.
Maker's packed size 31 x 24 x 24 cm: 31 x 24 x 24 = 17,856 cm³, so 17.9 L, in the 13 L+ band.
What reviewers say (out of 10)
Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score
Comfort to sleep in*
Estimate: only 1 review about comfort to sleep in (fewer than the 3 we need, so never above 8) 8/10How comfy the shape, hood and fabric feel; not the temperature rating.
1 review on comfort to sleep in, e.g. "die dicke, bequeme Kapuze und der selbsteinrastende Magnetverschluss am Wärmekragen".
In short
Good for
- Winter camps and high ground in the UK where the forecast is below -5 °C
- Trekkers and alpine users who want a lot of warmth for about 1.2 kg
- Cold sleepers who want the lab comfort figure to be -8 °C, not just the limit
Strengths
- Comfort -8 °C and limit -15 °C: among Mountain Equipment's warmest bags
- 795 g of 700+ fill duck down for 1,230 g all in
- Full-length Gemini zip baffle (140 cm zip), integrated draught collar and five-baffle hood, per the maker
- Waterproof roll-top stuff sack and a cotton storage cube in the box
Weaknesses
- Packs to about 17.9 L, a lot of rucksack space
- The down is not water-resistant treated, so a wet bag loses warmth
- Too warm for most UK summer nights
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (4)
- Mountain Equipment: Helium 800 product page (ISO 23537 ratings, weight, packed size)
- Ultralight Outdoor Gear: Helium 800 spec table (shop; weight 1,215 g, down treatment)
- Outdoor Magazin: Mountain Equipment Helium im Praxistest (Helium 800)
- Outdoor Magazin: Mountain Equipment Helium im Praxistest (Helium 800, 2-week test, 2023 redesign)