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ISO 23537 comfort vs limit

Comfort and lower-limit values are different outputs of the adult sleeping-bag test.

How to use this answer

For a cold sleeper, prioritize a documented comfort value and add margin. This separates a useful measurement from a broad product label and helps identify which exact variant needs further checking.

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Decision boundary

The listed values describe a product under its stated source conditions. They do not establish personal comfort, safety, stock, or fit in every shelter.

Temperature and fit context

ISO 23537-1:2022 describes adult bag testing under controlled conditions. Product labels and untested claims are not interchangeable with comfort or lower-limit numbers. A sleeping pad, clothing, humidity and individual metabolism change real comfort.

For this question, check: ISO comfort and lower limit where available, maximum user height, shoulder room, fill and actual pad insulation. When a particular specification is absent, keep the decision open rather than treating a missing value as zero or assuming a universal fit.

Compare actual recorded values

The values below come from exact catalog variants. The table is an illustration of which measurements to compare, not a ranking or a recommendation. Open each card for the field source and revision notes.

Exact variantProduct labelComfortListed weight
Western Mountaineering TerraLite — 84 in manufacturer size25°F (-3.9°C)28°F (-2.2°C)2.13 lb (964 g)
Western Mountaineering UltraLite — 78 in manufacturer size20°F (-6.7°C)25°F (-3.9°C)1.94 lb (879 g)
Western Mountaineering VersaLite — 78 in manufacturer size10°F (-12.2°C)21°F (-6.1°C)2.13 lb (964 g)

These records illustrate how the reported measurements and source links are presented; they are not personal field tests or ranked recommendations.

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Before you rely on a number

Recheck manufacturer instructions and the exact year, size and SKU. The October 30, 2026 dataset does not verify real-time inventory, sale prices, field performance or a guaranteed safe temperature. If the key measurement for this question is unavailable, ask the maker or measure your own equipment before committing to a setup.

Sources and further reading

Source pages and product listings can change. Specifications were assembled from the supplied dataset as of October 30, 2026; current availability is not guaranteed.