R1 (same-basis scenario)
- SI thermal resistance
- 0.176 m²·K/W
- Matching-basis U-value
- 5.678 W/(m²·K)
- US R-value
- 1 h·ft²·°F/BTU
VALICALC · TECHNICAL REFERENCE
R-Value & U-Value Conversion Chart
Compare US R-value, SI resistance and reciprocal U-values for authored examples. Preserve the same assembly basis and units before using a heat-loss input.
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Search within the verified subset. Numeric sizes match complete designations; a nearby size is a candidate, not an exact match.
SELECTED REFERENCE
R1 (same-basis scenario)
- SI thermal resistance
- 0.176 m²·K/W
- Matching-basis U-value
- 5.678 W/(m²·K)
- US R-value
- 1 h·ft²·°F/BTU
All fields & cell provenance
- Authored resistance: Thermal resistance and conductivity definitions — Original reciprocal resistance scenario; unit conversion from dimensional definitions · verified 2026-10-07 · source value R1 (same-basis scenario).
- SI thermal resistance: Thermal resistance and conductivity definitions — Original reciprocal resistance scenario; unit conversion from dimensional definitions · verified 2026-10-07.
- Matching-basis U-value: Thermal resistance and conductivity definitions — Original reciprocal resistance scenario; unit conversion from dimensional definitions · verified 2026-10-07.
- US R-value: Thermal resistance and conductivity definitions — Original reciprocal resistance scenario; unit conversion from dimensional definitions · verified 2026-10-07.
v1.3.0 · verified 2026-10-07
R1 (same-basis scenario)0.176 m²·K/WBack to answer ↑
Explore the verified data
12 matching rows · 12 in this subset
| Authored resistance | SI thermal resistance | Matching-basis U-value | US R-value | Actions |
|---|---|---|---|---|
| R1 (same-basis scenario) | 0.176 m²·K/W | 5.678 W/(m²·K) | 1 h·ft²·°F/BTU | |
| R2 (same-basis scenario) | 0.352 m²·K/W | 2.839 W/(m²·K) | 2 h·ft²·°F/BTU | |
| R3 (same-basis scenario) | 0.528 m²·K/W | 1.893 W/(m²·K) | 3 h·ft²·°F/BTU | |
| R5 (same-basis scenario) | 0.881 m²·K/W | 1.136 W/(m²·K) | 5 h·ft²·°F/BTU | |
| R8 (same-basis scenario) | 1.409 m²·K/W | 0.71 W/(m²·K) | 8 h·ft²·°F/BTU | |
| R10 (same-basis scenario) | 1.761 m²·K/W | 0.568 W/(m²·K) | 10 h·ft²·°F/BTU | |
| R13 (same-basis scenario) | 2.289 m²·K/W | 0.437 W/(m²·K) | 13 h·ft²·°F/BTU | |
| R19 (same-basis scenario) | 3.346 m²·K/W | 0.299 W/(m²·K) | 19 h·ft²·°F/BTU | |
| R30 (same-basis scenario) | 5.283 m²·K/W | 0.189 W/(m²·K) | 30 h·ft²·°F/BTU | |
| R38 (same-basis scenario) | 6.692 m²·K/W | 0.149 W/(m²·K) | 38 h·ft²·°F/BTU | |
| R49 (same-basis scenario) | 8.629 m²·K/W | 0.116 W/(m²·K) | 49 h·ft²·°F/BTU | |
| R60 (same-basis scenario) | 10.567 m²·K/W | 0.095 W/(m²·K) | 60 h·ft²·°F/BTU |
R2 (same-basis scenario)
- SI thermal resistance
- 0.352 m²·K/W
- Matching-basis U-value
- 2.839 W/(m²·K)
- US R-value
- 2 h·ft²·°F/BTU
R3 (same-basis scenario)
- SI thermal resistance
- 0.528 m²·K/W
- Matching-basis U-value
- 1.893 W/(m²·K)
- US R-value
- 3 h·ft²·°F/BTU
R5 (same-basis scenario)
- SI thermal resistance
- 0.881 m²·K/W
- Matching-basis U-value
- 1.136 W/(m²·K)
- US R-value
- 5 h·ft²·°F/BTU
R8 (same-basis scenario)
- SI thermal resistance
- 1.409 m²·K/W
- Matching-basis U-value
- 0.71 W/(m²·K)
- US R-value
- 8 h·ft²·°F/BTU
R10 (same-basis scenario)
- SI thermal resistance
- 1.761 m²·K/W
- Matching-basis U-value
- 0.568 W/(m²·K)
- US R-value
- 10 h·ft²·°F/BTU
R13 (same-basis scenario)
- SI thermal resistance
- 2.289 m²·K/W
- Matching-basis U-value
- 0.437 W/(m²·K)
- US R-value
- 13 h·ft²·°F/BTU
R19 (same-basis scenario)
- SI thermal resistance
- 3.346 m²·K/W
- Matching-basis U-value
- 0.299 W/(m²·K)
- US R-value
- 19 h·ft²·°F/BTU
R30 (same-basis scenario)
- SI thermal resistance
- 5.283 m²·K/W
- Matching-basis U-value
- 0.189 W/(m²·K)
- US R-value
- 30 h·ft²·°F/BTU
R38 (same-basis scenario)
- SI thermal resistance
- 6.692 m²·K/W
- Matching-basis U-value
- 0.149 W/(m²·K)
- US R-value
- 38 h·ft²·°F/BTU
R49 (same-basis scenario)
- SI thermal resistance
- 8.629 m²·K/W
- Matching-basis U-value
- 0.116 W/(m²·K)
- US R-value
- 49 h·ft²·°F/BTU
R60 (same-basis scenario)
- SI thermal resistance
- 10.567 m²·K/W
- Matching-basis U-value
- 0.095 W/(m²·K)
- US R-value
- 60 h·ft²·°F/BTU
How to use this data
RSI=RUS×0.1761101838; matching SI U=1/RSI. Imperial U uses the reciprocal of US R on that same basis. No Heat Loss row is auto-filled.
CHECK THE METHOD
Worked example
R19 corresponds to RSI 3.34609 and matching U≈0.298856 W/(m²·K). This does not make an R19 batt an R19 wall assembly.
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Common lookup questions
What should I confirm before using this lookup?
Material-only resistance is not a whole-assembly rating. Framing, bridges, films, gaps, moisture and installation can change actual R/U; no climate-zone/code target is assigned.
TRACEABLE DATA
Sources, scope & verification
Dataset v1.3.0
Last verified:
12 authored reciprocal comparisons; no material, product or whole-building code values.
Values are curated product facts or generated scenarios. Paid standards, complete catalogs and source diagrams are not reproduced. A verification date applies to this documented subset.
Thermal resistance and conductivity definitions ↗
Type A · US Bureau of Standards · Letter Circular 227: Thermal Insulation, 1927; definitions only
Original equations, chosen scenarios and generated values; no copied tables or drawings.
Full provenance & artifact record
- Source checked
- 2026-10-07
- Use basis
- authored-formula
- Artifact SHA-256
- No retained source artifact hash; see the stated source and verification record.
SI and customary-unit conversions ↗
Type A · NIST · SP 1038, 2006; exact definitions used where available
Original equations, chosen scenarios and generated values; no copied tables or drawings.
Full provenance & artifact record
- Source checked
- 2026-10-07
- Use basis
- authored-formula
- Artifact SHA-256
- No retained source artifact hash; see the stated source and verification record.