How We Test

Our goal is simple: translate lab ratings into real‑world comfort so you can choose a system that sleeps warm for you. We combine controlled measurements with field nights across climates, then map results into our Real Warmth Index to show expected comfort temperatures by setup and sleeper profile.

Test Philosophy

A sleeping bag never works alone. We evaluate the full sleep system—bag or quilt, pad, shelter, sleepwear, and technique—because drafts, compression, humidity, and ground conduction change the outcome more than a few ounces of down.

Protocols and Instruments

• Environmental ranges: 10°F to 55°F across dry alpine, shoulder‑season wind, and high‑humidity coastal conditions
• Shelter contexts: double‑wall tents, single‑wall shelters, tarps, and bivies; hammock rigs with underquilts and pad alternatives
• Sensors: thermal mannequins and skin‑proximate loggers for neck, torso, hips, and feet; pad surface and ground contact temps; humidity and wind probes
• Fit mapping: shoulder/hip circumference and height ranges to identify compression and gap risks for side sleepers and broad/tall bodies

Real Warmth Index (RWI)

We translate ISO/EN ratings into expected comfort by applying adjustments for pad R‑value, shelter type, humidity, wind, and fit. The RWI outputs a practical range (comfortable, caution, and emergency margins) and notes when a pad upgrade beats a bag swap.

Field Validation

Each product gets a minimum number of nights across contrasting conditions. Hot and cold sleepers validate edges of the range. Hammock and ground tests are run separately, and family testers assess roomy rectangular and double systems.

Moisture and Draft Protocols

We simulate condensation, damp down, and frost events, then measure recovery with venting and active drying. Draft resistance is stress‑tested with zipper guards, baffles, collars, and quilt strap systems.

Ratings and Recommendations

We report:

• Expected comfort temp by system with safety buffer
• Best‑fit body shapes and sleep positions
• When to add liners or clothing and when to step up a rating
• Budget and weight trade‑offs with suggested upgrade paths

Sample Sourcing and Independence

We acquire samples via retail purchase, short‑term loans, or brand‑provided units. Source never affects scores. Retail units are prioritized when feasible. All methodology and updates are documented for transparency.

If you’re a brand or reader with data that challenges our findings, reach out—replication makes everyone warmer.