Btus (IT)/hour/square foot/°F to Watts/square meter kelvin Converter (Btu/(h·ft²·°F) to W/(m²·K))
Btu/(h·ft²·°F) × 5.67826926 = W/(m²·K)
Calculation: 1 Btu/(h·ft²·°F) × 5.67826926 = 5.67826926 W/(m²·K)
Common Btu (IT)/hour/square foot/°F to Watt/square meter kelvin Calculations
Quick-lookup reference table showing calculated equivalents for standard increments between Btu (IT)/hour/square foot/°F (Btu/(h·ft²·°F)) and Watt/square meter kelvin (W/(m²·K)).
| Conversion & Equivalent Value | Scientific Notation |
|---|---|
| 0.001 Btu/(h·ft²·°F) 0.00567827 W/(m²·K) | 5.678 × 10⁻³ |
| 0.01 Btu/(h·ft²·°F) 0.0567827 W/(m²·K) | 5.678 × 10⁻² |
| 0.1 Btu/(h·ft²·°F) 0.567827 W/(m²·K) | 5.678 × 10⁻¹ |
| 0.5 Btu/(h·ft²·°F) 2.839135 W/(m²·K) | 2.839 × 10⁰ |
| 1 Btu/(h·ft²·°F) 5.678269 W/(m²·K) | 5.678 × 10⁰ |
| 2 Btu/(h·ft²·°F) 11.356539 W/(m²·K) | 1.136 × 10¹ |
| 5 Btu/(h·ft²·°F) 28.391346 W/(m²·K) | 2.839 × 10¹ |
| 10 Btu/(h·ft²·°F) 56.782693 W/(m²·K) | 5.678 × 10¹ |
| 20 Btu/(h·ft²·°F) 113.565385 W/(m²·K) | 1.136 × 10² |
| 25 Btu/(h·ft²·°F) 141.956732 W/(m²·K) | 1.42 × 10² |
| 50 Btu/(h·ft²·°F) 283.913463 W/(m²·K) | 2.839 × 10² |
| 100 Btu/(h·ft²·°F) 567.826926 W/(m²·K) | 5.678 × 10² |
| 250 Btu/(h·ft²·°F) 1419.567316 W/(m²·K) | 1.42 × 10³ |
| 500 Btu/(h·ft²·°F) 2839.134632 W/(m²·K) | 2.839 × 10³ |
| 1000 Btu/(h·ft²·°F) 5678.269264 W/(m²·K) | 5.678 × 10³ |
| Reciprocal & Equivalent Value | Scientific Notation |
|---|---|
| 1 W/(m²·K) 0.17611 Btu/(h·ft²·°F) | 1.761 × 10⁻¹ |
| 5 W/(m²·K) 0.88055 Btu/(h·ft²·°F) | 8.806 × 10⁻¹ |
| 10 W/(m²·K) 1.7611 Btu/(h·ft²·°F) | 1.761 × 10⁰ |
| 50 W/(m²·K) 8.8055 Btu/(h·ft²·°F) | 8.806 × 10⁰ |
| 100 W/(m²·K) 17.611 Btu/(h·ft²·°F) | 1.761 × 10¹ |
Real-World Context & Everyday Benchmarks
Tap to load into converterTo help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for Btu (IT)/hour/square foot/°F (Btu/(h·ft²·°F)) and Watt/square meter kelvin (W/(m²·K)):
Btu (IT)/hour/square foot/°F References:
- Standard modern residential double-pane window U-factor 0.28 Btu/(h·ft²·°F)
- Still interior air film natural convection on drywall surface 1.46 Btu/(h·ft²·°F)
- Winter 15 mph wind exterior building wall surface air film 6 Btu/(h·ft²·°F)
Watt/square meter kelvin References:
- Stationary ambient air natural free convection on vertical wall 5 W/(m²·K)
- Forced air breeze blowing across automotive cooling radiator 50 W/(m²·K)
- Liquid water forced circulation inside heat exchanger pipe 3000 W/(m²·K)
- Nucleate boiling heat transfer in pressurized steam boiler tube 15000 W/(m²·K)
- Dropwise pure steam condensation on chilled titanium surface 50000 W/(m²·K)
How to Convert Btu (IT)/hour/square foot/°F to Watt/square meter kelvin
Converting Btu (IT)/hour/square foot/°F (Btu/(h·ft²·°F)) to Watt/square meter kelvin (W/(m²·K)) is a core calculation in Heat Transfer Coefficient, which quantifies the proportionality constant between the heat flux and the thermodynamic driving temperature difference. This calculation navigates the boundary between the International Metric System (SI) and British Imperial / US Customary engineering standards. In contemporary metrology, Imperial units are defined in terms of exact SI standards via international agreements—notably NIST SP 811 and the 1959 International Yard and Pound Agreement. Exactly 1 Btu (IT)/hour/square foot/°F equals 5.678269 Watt/square meter kelvin, while 1 W/(m²·K) equals 0.17611 Btu/(h·ft²·°F).
Mathematical Conversion Derivation via Coherent SI Base Unit
Under the International System of Quantities (ISQ), dimensional conversion between non-SI units is rigorously resolved by bridging through the coherent SI base unit (watt per square meter kelvin (W/(m²·K))) without arbitrary rounding:
1 Btu/(h·ft²·°F) = 5.678269 watt per square meter kelvin (W/(m²·K))1 W/(m²·K) = 1 watt per square meter kelvin (W/(m²·K))V(W/(m²·K)) = V(Btu/(h·ft²·°F)) × ( 5.678269 / 1 ) = V(Btu/(h·ft²·°F)) × 5.678269Value in Watt/square meter kelvin = Value in Btu (IT)/hour/square foot/°F × 5.67826926Direct computational formula applied for standard conversion.To convert 50 Btu (IT)/hour/square foot/°F (Btu/(h·ft²·°F)) to Watt/square meter kelvin (W/(m²·K)): multiply 50 by 5.678269 to get 283.913463 W/(m²·K). At an industrial engineering scale, 100 Btu/(h·ft²·°F) converts to 567.826926 W/(m²·K).
Inverse check: 1 W/(m²·K) = 0.17611 Btu/(h·ft²·°F).Understanding Btu (IT)/hour/square foot/°F and Watt/square meter kelvin
Btu (IT)/hour/square foot/°F
Btu/(h·ft²·°F)A Btu (IT)/hour/square foot/°F (Btu/(h·ft²·°F)) is an imperial and US customary unit for heat transfer coefficient.
Applications & Practical Context
In practical heat transfer coefficient terms, a standard modern residential double-pane window U-factor equals 0.28 Btu/(h·ft²·°F), a still interior air film natural convection on drywall surface equals 1.46 Btu/(h·ft²·°F), a winter 15 mph wind exterior building wall surface air film equals 6 Btu/(h·ft²·°F).
A physical magnitude of 1 Btu/(h·ft²·°F) corresponds to 5.678269 W/(m²·K) in standard SI measurement.
1 Btu/(h·ft²·°F) = 5.678269 W/(m²·K)Watt/square meter kelvin
W/(m²·K)A Watt/square meter kelvin (W/(m²·K)) is the official base standard unit for heat transfer coefficient.
Applications & Practical Context
In practical heat transfer coefficient terms, a stationary ambient air natural free convection on vertical wall equals 5 W/(m²·K), a forced air breeze blowing across automotive cooling radiator equals 50 W/(m²·K), a liquid water forced circulation inside heat exchanger pipe equals 3000 W/(m²·K).
A heat transfer coefficient of 1 W/(m²·K) yields 1 watt of thermal energy transfer per square meter for each kelvin difference.
1 W/(m²·K) = 1 W/(m²·K) (Base Standard)Domain Metrology & Engineering Applications
Newton's Law of Cooling (q = h · ΔT)
Rigorously quantified in laboratory and field settings using surface heat flux transducer plates coupled with surface RTD arrays, and wind tunnel boundary layer calorimeters.
Applied across industrial heat exchanger rating, nuclear reactor cooling loop simulation, electronics forced-air cooling, and architectural U-value certification under international metrology standard ISO 80000-5:2019, ASME PTC.
Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-5:2019, ASME PTC and the BIPM SI Brochure (9th Edition). Governed by Newton's Law of Cooling (q = h · ΔT) under ISO 80000 dimensional vector [M T⁻³ Θ⁻¹].
Heat Transfer Coefficient to Convective Flux Bridge (W/m² • kW/m² • BTU/(h·ft²) • cal/(s·cm²))
Calculate Newton’s law of cooling convective heat flux q" = h × ΔT across convective film temperature drops, bridging heat transfer coefficient [M T⁻³ Θ⁻¹] with heat flux [M T⁻³].
q" = h × ΔT
[W/(m²·K)] × [K] → [W/m²]
-
1. Normalize Input to SI Base Unit (W/(m²·K)):
h = 1 Btu/(h·ft²·°F) × 5.67826926 = 5.67826926 W/(m²·K) -
2. Apply Engineering Parameter (ΔT):
Selected condition: Forced Air Duct Cooling (ΔT = 25 K) at ΔT = 25 K -
3. Execute Governing Physical Law in SI Units:
q" = h × ΔT = (5.67826926 W/(m²·K)) × (25 K) = 141.956732 W/m² -
4. Convert to Standard Engineering Units:
• W/m²: 141.956732 × 1 = 141.9567 W/m² (Watts per Square Meter) • kW/m²: 141.956732 × 0.001 = 0.142 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 141.956732 × 0.317 = 45.0001 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 141.956732 × 2.3885 × 10⁻⁵ = 0.00339058 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 141.956732 × 0.001433 = 0.2035 Ly/min (Langley per Minute) • MW/m²: 141.956732 × 1 × 10⁻⁶ = 0.00014196 MW/m² (Megawatts per Square Meter)
| Engineering Substance / Operating Standard | Parameter Value (K) | Reference State / Condition | Typical Industrial & Engineering Application |
|---|---|---|---|
| Natural Air Convection (ΔT = 15 K) | 15 |
ΔT = 15 K (15°C) | Still room air room heating surface delta |
| Forced Air Duct Cooling (ΔT = 25 K) | 25 |
ΔT = 25 K (25°C) | Forced fan ventilation heatsink airflow |
| Forced Liquid Water Cooling (ΔT = 30 K) | 30 |
ΔT = 30 K | Pumped liquid cold plate or engine jacket |
| Nucleate Boiling Heat Transfer (ΔT = 50 K) | 50 |
ΔT = 50 K | Boiler evaporator tube wall boundary |
Frequently Asked Questions
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