Clo
The clo measures the thermal insulation of clothing: 1 clo (0.155 m²·K/W) keeps a resting person comfortable at about 21 °C. Summer clothing is about 0.5 clo, a business suit 1 clo.
Symbol: clo
Quantity: thermal resistance per unit area (insulation R-value)
SI relation: 1 clo = 0.155 m²·K/W (exact)
Derivation: 1 clo = 0.155 m²·K/W (ISO 7730, ASHRAE 55).
Exact: yes, by definition
Typical uses
- Thermal comfort (PMV/PPD) in ASHRAE 55 and ISO 7730
- Clothing and textile insulation
- Sleeping-bag and outdoor-gear ratings
Convert clo to other units
| Conversion | 1 clo equals | Reverse |
|---|---|---|
| clo to RSI | 0.155 m²·K/W | RSI to clo |
| clo to R (US) | 0.8801308179 ft²·°F·h/BTU | R (US) to clo |
| clo to tog | 1.55 tog | tog to clo |
| clo to square metre hour degree Celsius per kilocalorie | 0.180265 m²·h·°C/kcal | square metre hour degree Celsius per kilocalorie to clo |
Open the R-Value Converter (US R to RSI, m²·K/W) to convert any value between all units.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "clo".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Clo. Retrieved October 29, 2026, from https://scientificconverters.com/units/clo/
IEEE
Scientific Converters, "Clo," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/units/clo/