The comfort rating, not the season name, describes your night
Two bags described as three-season can be ten degrees apart, because the phrase means nothing and the numbers underneath it mean a great deal. Bags tested to EN 13537 or its successor ISO 23537 carry a comfort figure and a limit figure, measured on a heated mannequin rather than on people, and the comfort figure is the one to compare. A third figure sometimes appears at the bottom of the label; it is not a temperature to plan a night around and we do not rank on it. Insulation then splits two ways. Down is rated by fill power, the volume a fixed mass lofts to, and a high fill power alone tells you nothing until you also read the fill weight — the grams actually in the bag. Synthetic is heavier and bulkier for the same stated rating, keeps more loft when damp, and costs less. Around the insulation, read the shell denier, the baffle construction that stops down migrating to one side, and whether the maker states a hydrophobic treatment. Finally the fit: length, shoulder girth and foot box shape decide dead air, and dead air is what the rating assumes. We compare stated comfort and limit ratings and the standard quoted, fill power and fill weight, down or synthetic, shell denier, baffle construction, packed size and weight.
Mummy with hood · synthetic fill · comfort range given as 5 °C to 25 °C · 210 × 73 cm · no standard named
A hooded mummy bag that publishes a comfort range twenty degrees wide, names no standard behind it, and gives neither a weight nor a packed size.
Best for: Warm-weather camping close to the car, where the 210 cm length and the blanket conversion matter more than a carried weight.
≈ 15 €
Mummy · 400 GSM synthetic · comfort +4 °C and limit -2 °C stated · 1.55 kg total · compression sack · no standard named
The only bag here to publish a comfort and a limit figure separately — and, like every other bag in this group, it names no standard behind them.
Best for: Three-season camping where a stated comfort and limit pair matters more than a published packed size.
≈ 23 €
Mummy · 350 GSM double-layer fill · comfort around 0 °C stated · 1900 g · 24 × 30 cm packed · 230 × 82 × 55 cm
A large mummy bag that names a comfort temperature of around 0 °C, publishes weight, packed size and a full cut, and names no standard behind the figure.
Best for: Taller sleepers camping in the cold shoulder seasons, where a 230 cm bag and a stated comfort figure matter more than carried weight.
≈ 70 €
Mummy · 300 g/m² fill · 1550 g · 38 × 23 cm packed · 215 × 85 (55) cm · a pair of unlabelled temperatures
A mummy bag that publishes weight, packed size and a tapered cut, and puts two temperatures in its title without saying which is which.
Best for: Cold-weather camping where a 1550 g bag with a thermal collar and a known taper is what is wanted.
≈ 46 €
Mummy · 300 GSM cotton and hollow-fibre fill · comfort 15 °C to 20 °C · about 1300 g · 35 × 25 cm packed
A three-season mummy bag that publishes weight, packed size and fill density, and puts its comfort range at 15 °C to 20 °C with no standard behind it.
Best for: Spring to autumn trips where about 1300 g into a 35 × 25 cm roll is the constraint that matters.
≈ £49 / 40 €
Mummy with hood · 300 GSM · range given as 8 °C to -5 °C with neither end labelled · DWR outer · pillow included
A hooded mummy bag that publishes a temperature range without saying which end is comfort, and gives neither a weight nor a packed size.
Best for: Cooler-weather camping where the bag is driven to the pitch and a pillow in the box is worth having.
≈ £52 / 45 €
Rectangular · hollow-fibre fill · comfort range 10 °C to 20 °C · S-shaped quilting · 30 × 22 cm packed · 1.35 kg
A rectangular three-season bag that publishes its packed size, its weight and its quilting pattern — and, like the rest of this shelf, names no standard for its comfort range.
Best for: Spring to autumn camping and guest-bed duty, where the blanket conversion and a known packed size matter more than a low limit.
≈ 19 €
Half-rectangular · comfort quoted in Fahrenheit only · side and foot zips · no weight, no packed size, no fill published
A half-rectangular bag whose only figures are two Fahrenheit ranges, with no weight, no packed size, no fill and no fabric published anywhere.
Best for: Warm-weather use where the foot vent and the full opening matter, and where nothing has to be carried far.
≈ £21 / 31 €
Down · 650 fill power · 85 % down content · comfort above 5 °C and limit 0 °C stated · 20D nylon shell · 760 g / 885 g
The only down bag in this group: it publishes a fill power, a down content, a shell denier and a comfort and limit pair — and still names no standard.
Best for: Backpacking in mild conditions where 760 g and a 650 fill power down bag are the reason for the purchase.
≈ £116 / 110 €
This family belongs to the sleeping out kit — see everything that has to work with it.
Prices in these summaries were read on the dates each review gives. The live figure sits beside every product.
