Convert Clo to US R-Value (clo to ft2 F h/BTU)
1 clo = 0.8801308179 US R-value (ft²·°F·h/BTU). 1 ft²·°F·h/BTU = 1.136194733 clo. Example: 15 clo = 15 × 0.8801308179 = 13.20196227 ft²·°F·h/BTU.
Also searched as clo to ft2 F h/BTU, clo in ft2 F h/BTU, clo into US R-value, clo in US R-value, clo to US R-value, clo to US R-value converter and how many US R-value in a clo.
1 clo = 0.8801308179 ft²·°F·h/BTU
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk clo to R (US) converter to paste a column from Excel.
How to Convert Clo to US R-Value
- 1 clo = 0.8801308179 ft²·°F·h/BTU
- 1 ft²·°F·h/BTU = 1.136194733 clo
- Example: convert 15 clo to ft²·°F·h/BTU: 15 clo = 15 × 0.8801308179 ft²·°F·h/BTU = 13.20196227 ft²·°F·h/BTU
Formula
ft²·°F·h/BTU = clo × 0.8801308178726
or ft²·°F·h/BTU = clo ÷ 1.136194733434
Derivation from SI units:
- 1 clo = 0.155 m²·K/W (ISO 7730, ASHRAE 55).
- 1 ft²·°F·h/BTU_IT = 0.09290304 m² × (5/9) K × 3600 s ÷ 1055.05585262 J ≈ 0.17611 m²·K/W.
- 1 clo = 0.155 m²·K/W ÷ 0.1761101836823 m²·K/W per ft²·°F·h/BTU = 0.8801308178726 ft²·°F·h/BTU
Both units are defined exactly, so the factor is exact. Clo definition: clo; US R-Value definition: US R-value.
Worked examples
- A reading of 0.7 clo converts to 0.6160915725 ft²·°F·h/BTU.
0.7 clo × 0.8801308179 = 0.6160915725 ft²·°F·h/BTU - A value of 1.5 clo is 1.320196227 ft²·°F·h/BTU.
1.5 clo × 0.8801308179 = 1.320196227 ft²·°F·h/BTU
Clo to US R-Value conversion table
| Clo | US R-Value (ft²·°F·h/BTU) |
|---|---|
| 0.3 clo | 0.2640392454 ft²·°F·h/BTU |
| 0.5 clo | 0.4400654089 ft²·°F·h/BTU |
| 0.6 clo | 0.5280784907 ft²·°F·h/BTU |
| 0.7 clo | 0.6160915725 ft²·°F·h/BTU |
| 1 clo | 0.8801308179 ft²·°F·h/BTU |
| 1.2 clo | 1.056156981 ft²·°F·h/BTU |
| 1.5 clo | 1.320196227 ft²·°F·h/BTU |
| 2 clo | 1.760261636 ft²·°F·h/BTU |
| 3 clo | 2.640392454 ft²·°F·h/BTU |
| 4 clo | 3.520523271 ft²·°F·h/BTU |
Where it's used
Clo are used for thermal comfort (PMV/PPD) in ASHRAE 55 and ISO 7730, while US R-value appear in US insulation labels (R-13, R-19, R-38). Both measure thermal resistance per unit area (insulation R-value), so the conversion is a fixed factor.
Clo to other thermal resistance (r-value) units
| Conversion | 1 clo equals |
|---|---|
| clo to R (US) | 0.8801308179 ft²·°F·h/BTU |
| clo to RSI | 0.155 m²·K/W |
| clo to tog | 1.55 tog |
| clo to square metre hour degree Celsius per kilocalorie | 0.180265 m²·h·°C/kcal |
Frequently asked questions
How many US R-value are in 1 clo?
1 clo = 0.8801308179 ft²·°F·h/BTU.
How do I convert clo to US R-value?
Multiply the value in clo by 0.8801308179, or divide it by 1.136194733. For example, 15 clo × 0.8801308179 = 13.20196227 ft²·°F·h/BTU.
Is the clo to ft²·°F·h/BTU conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
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".
- 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, "degree Fahrenheit hour square foot per British thermal unit_IT".
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). Convert Clo to US R-Value (clo to ft2 F h/BTU). Retrieved October 29, 2026, from https://scientificconverters.com/thermal-resistance/clo-to-r-value/
IEEE
Scientific Converters, "Convert Clo to US R-Value (clo to ft2 F h/BTU)," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/thermal-resistance/clo-to-r-value/