Primus
Primus Ulti Stove System 1.0L
- Weight: 3/10 How much it adds to your pack.
- Fuel use: 5/10 How much fuel it burns to boil a litre in calm air: less fuel to carry.
- Boil speed (calm air): 8/10 How fast the maker says it boils 1 litre in calm air.
Winter and high-altitude camps where fast boils in wind and cold matter
- Fuel
- Gas
- Weight
- 600 g
- Pot size
- 1 L
- Boil 1 L, calm air
- 3:30
- Fuel per litre
- Not published
Packed size 14.4 cm long and 13 cm across Compare with a 2-litre bottle
Shorter than a 2-litre bottle and a bit wider than one. Drawn to scale.
Where to buy
Fresh Air Junkie £214.99 In stock. Free delivery. Free UK mainland delivery under 3 kg. Page shows a compare price of £285.00. Only 4 units left when checked.
View at shop: Fresh Air JunkieAlpinetrek £242.69 In stock. Free delivery. Free delivery from £85. Price includes duties and taxes; page shows a crossed-out £278.95 and a delivery time of 5-7 working days.
View at shop: AlpinetrekPrimus £284.99 In stock. Free delivery. Free delivery over £49, £6 under (Primus UK shipping policy page).
View at shop: PrimusPrices 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
Weight
From maker's figures 3/10How much it adds to your pack. 3: Below average. Fine for some trips, not others.
Primus gives 600 g (specification table), in the 450-649 g band. UKC gives 620 g for burner and pot; Hikers Blog quotes 600 g. Fresh Air Junkie's page lists 500 g, which doesn't match Primus.
Fuel use
Estimate from maker's specs: fuel type (no fuel use figure published) 5/10How much fuel it burns to boil a litre in calm air: less fuel to carry. 5: Does the job. Average for wild-camping gear.
Estimate from maker's specs
Boil speed (calm air)
From maker's figures 8/10How fast the maker says it boils 1 litre in calm air. 8: Clearly better than most.
Primus says 1 litre in 3 min 30 s (210 s): its specification table gives 3:30 without a volume, and its copy says the burner 'boils 1 litre of water in just 3.5 minutes'. That is in the 210-269 s band and right on the line. UKC timed 4 min 00 s for 1 litre at sea level with tap-cold water and a full canister at room temperature, and 2 min 10 s for 0.5 litre indoors (the MSR Reactor took 1 min 46 s). GearJunkie found it about 30 s slower than a Jetboil.
In short
Good for
- Winter and high-altitude camps where fast boils in wind and cold matter
- Solo walkers and pairs who only boil water for drinks and freeze-dried meals
- Exposed pitches: UKC and GearJunkie both found the flameless burner holds in wind that would blow out an open flame
Strengths
- Flameless radiant burner under a heat-exchanger pot: UKC found it as wind-proof as an MSR Reactor
- Primus quotes 1 litre in 3 min 30 s; UKC timed 4 min 00 s at sea level and 2 min 10 s for 0.5 litre
- Remote canister on a hose, so the stove sits low and stable on three folding legs and the canister can be inverted in deep cold (UKC, Hikers Blog)
- Regulated output keeps power steady as the canister empties (UKC)
- Locking handle and lid loop are better than the Reactor's (UKC, Hikers Blog)
- Primus sells it for 'high altitudes and extreme cold' and for melting snow, so we mark it winter-ready from Primus's own words
Weaknesses
- 600 g is heavy for a 1-litre system: UKC weighed 620 g and lists the Reactor 1.0 at 420 g
- The 1.0 L pot holds the burner but not a 100 g canister (UKC, Hikers Blog)
- No igniter, and the pot does not lock to the burner (UKC); good for boiling water only (UKC, GearJunkie)
- Chris Woollard's first Ulti, a 1.0 L, melted in use with a Coleman propane-butane canister. Primus replaced it, and the updated instructions he shows in the box name only its Power Gas or Winter Gas (propane and isobutane); Primus's page says not to use butane gas
- Primus gives no litres-per-canister figure
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (6)
- Primus: Ulti Stove System 1.0L product page (specification table: weight, boil time, size)
- UKC Gear (Dan Bailey): Primus Ulti Stove System - Finally, a rival to the Reactor?
- GearJunkie (Will Brendza): Wind-Resistant, Infrared Stove Thrives in Harsh Conditions: Primus Ulti Stove 1.0 Review
- Hikers Blog: Primus Ulti Stove Review
- Chef Corso (YouTube): The ultimate backpacking stove showdown: MSR Reactor vs Primus Ulti
- Chris Woollard (YouTube): Primus Ulti Replacement Review (his 1.0 L melted with propane-butane gas; replacement 1.7 L unboxed)