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Btus (th)/hour/square foot/°F to Joules/second/square meter/K Converter (Btu (th)/(h·ft²·°F) to J/(s·m²·K))

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Live Conversion • ISO 80000-5:2019 Certified
1 Btu (th)/hour/square foot/°F = 5.67446717 Joule/second/square meter/K
1 Btu (th)/(h·ft²·°F) = 5.674467 J/(s·m²·K) • 1 J/(s·m²·K) = 0.176228 Btu (th)/(h·ft²·°F)
Btu (th)/hour/square foot/°F to Joule/second/square meter/K: One Btu (th)/hour/square foot/°F is equal to 5.67446717 Joules/second/square meter/K.
Certified Authority Value
5.67446717
J/(s·m²·K)
Exact: 1 J/(s·m²·K) ≡ 0.176228 Btu (th)/(h·ft²·°F)
Btu (th)/(h·ft²·°F)
Btu (th)/(h·ft²·°F)
Swap to Joule/second/square meter/K to Btu (th)/hour/square foot/°F
Swap to Joule/second/square meter/K to Btu (th)/hour/square foot/°F
J/(s·m²·K)
J/(s·m²·K) 5.67446717
Quick Values:
Conversion Formula
To convert Btu (th)/hour/square foot/°F to Joule/second/square meter/K, multiply by 5.67446717
Btu (th)/(h·ft²·°F) × 5.67446717 = J/(s·m²·K)

Calculation: 1 Btu (th)/(h·ft²·°F) × 5.67446717 = 5.67446717 J/(s·m²·K)

Common Btu (th)/hour/square foot/°F to Joule/second/square meter/K Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between Btu (th)/hour/square foot/°F (Btu (th)/(h·ft²·°F)) and Joule/second/square meter/K (J/(s·m²·K)).

Tap any row to calculate
Btu (th)/hour/square foot/°F to Joule/second/square meter/K: Primary Direct Table (15 Steps)
Btu (th)/hour/square foot/°F to Joule/second/square meter/K Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu (th)/(h·ft²·°F) 0.00567447 J/(s·m²·K) 5.674 × 10⁻³
0.01 Btu (th)/(h·ft²·°F) 0.0567447 J/(s·m²·K) 5.674 × 10⁻²
0.1 Btu (th)/(h·ft²·°F) 0.567447 J/(s·m²·K) 5.674 × 10⁻¹
0.5 Btu (th)/(h·ft²·°F) 2.837234 J/(s·m²·K) 2.837 × 10⁰
1 Btu (th)/(h·ft²·°F) 5.674467 J/(s·m²·K) 5.674 × 10⁰
2 Btu (th)/(h·ft²·°F) 11.348934 J/(s·m²·K) 1.135 × 10¹
5 Btu (th)/(h·ft²·°F) 28.372336 J/(s·m²·K) 2.837 × 10¹
10 Btu (th)/(h·ft²·°F) 56.744672 J/(s·m²·K) 5.674 × 10¹
20 Btu (th)/(h·ft²·°F) 113.489343 J/(s·m²·K) 1.135 × 10²
25 Btu (th)/(h·ft²·°F) 141.861679 J/(s·m²·K) 1.419 × 10²
50 Btu (th)/(h·ft²·°F) 283.723358 J/(s·m²·K) 2.837 × 10²
100 Btu (th)/(h·ft²·°F) 567.446717 J/(s·m²·K) 5.674 × 10²
250 Btu (th)/(h·ft²·°F) 1418.616792 J/(s·m²·K) 1.419 × 10³
500 Btu (th)/(h·ft²·°F) 2837.233584 J/(s·m²·K) 2.837 × 10³
1000 Btu (th)/(h·ft²·°F) 5674.467168 J/(s·m²·K) 5.674 × 10³
Joule/second/square meter/K to Btu (th)/hour/square foot/°F: Reciprocal Summary
Joule/second/square meter/K to Btu (th)/hour/square foot/°F Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 J/(s·m²·K) 0.176228 Btu (th)/(h·ft²·°F) 1.762 × 10⁻¹
5 J/(s·m²·K) 0.88114 Btu (th)/(h·ft²·°F) 8.811 × 10⁻¹
10 J/(s·m²·K) 1.76228 Btu (th)/(h·ft²·°F) 1.762 × 10⁰
50 J/(s·m²·K) 8.8114 Btu (th)/(h·ft²·°F) 8.811 × 10⁰
100 J/(s·m²·K) 17.6228 Btu (th)/(h·ft²·°F) 1.762 × 10¹
View Complete 15-Row Joule/second/square meter/K to Btu (th)/hour/square foot/°F Table

Real-World Context & Everyday Benchmarks

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To help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for Btu (th)/hour/square foot/°F (Btu (th)/(h·ft²·°F)) and Joule/second/square meter/K (J/(s·m²·K)):

Btu (th)/hour/square foot/°F References:

  • Heavy masonry uninsulated cavity wall overall U-factor 0.45 Btu (th)/(h·ft²·°F)

Joule/second/square meter/K References:

  • Equivalent to W/(m²·K): Forced water cooling jacket convection 2500 J/(s·m²·K)

Tap any benchmark above to automatically calculate its exact equivalent in Joule/second/square meter/K.

ISQ Dimension: [M T⁻³ Θ⁻¹] Coherent SI Unit: watt per square meter kelvin (W/(m²·K)) Thermodynamics & Heat Transfer

How to Convert Btu (th)/hour/square foot/°F to Joule/second/square meter/K

Converting Btu (th)/hour/square foot/°F (Btu (th)/(h·ft²·°F)) to Joule/second/square meter/K (J/(s·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 (th)/hour/square foot/°F equals 5.674467 Joule/second/square meter/K, while 1 J/(s·m²·K) equals 0.176228 Btu (th)/(h·ft²·°F).

Direct Factor1 Btu (th)/(h·ft²·°F) = 5.674467 J/(s·m²·K)
Inverse Ratio1 J/(s·m²·K) = 0.176228 Btu (th)/(h·ft²·°F)
Conversion ScaleMetric SI to British Imperial / US Customary Bridge
First-Principles SI Derivation ProofNIST SP 811 / ISO 80000 Compliance

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:

Vtarget=Vsource×(ksource→SIktarget→SI)V_{\text{target}} = V_{\text{source}} \times \left( \frac{k_{\text{source} \to \text{SI}}}{k_{\text{target} \to \text{SI}}} \right)
Universal Dimensional Conversion Law (ISO 80000 / NIST SP 811)
1. Source SI Bridge (ksource):1 Btu (th)/(h·ft²·°F) = 5.674467 watt per square meter kelvin (W/(m²·K))
2. Target SI Bridge (ktarget):1 J/(s·m²·K) = 1 watt per square meter kelvin (W/(m²·K))
Step-by-step substitution for Btu (th)/hour/square foot/°F → Joule/second/square meter/K:V(J/(s·m²·K)) = V(Btu (th)/(h·ft²·°F)) × ( 5.674467 / 1 ) = V(Btu (th)/(h·ft²·°F)) × 5.674467
Mathematical FormulaValue in Joule/second/square meter/K = Value in Btu (th)/hour/square foot/°F × 5.67446717Direct computational formula applied for standard conversion.
Worked Example

Evaluating an input of 12 Btu (th)/hour/square foot/°F (Btu (th)/(h·ft²·°F)) produces 68.093606 Joule/second/square meter/K (J/(s·m²·K)). In heavy-duty utility and industrial workloads, 2500 Btu (th)/(h·ft²·°F) equals 14186.167919 J/(s·m²·K).

Inverse check: 1 J/(s·m²·K) = 0.176228 Btu (th)/(h·ft²·°F).

Understanding Btu (th)/hour/square foot/°F and Joule/second/square meter/K

Btu (th)/hour/square foot/°F

Btu (th)/(h·ft²·°F)
Imperial / US

A Btu (th)/hour/square foot/°F (Btu (th)/(h·ft²·°F)) is an imperial and US customary unit for heat transfer coefficient.

Applications & Practical Context

In practical heat transfer coefficient terms, a heavy masonry uninsulated cavity wall overall U-factor equals 0.45 Btu (th)/(h·ft²·°F).

Physical Setup

A physical magnitude of 1 Btu (th)/(h·ft²·°F) corresponds to 5.674467 W/(m²·K) in standard SI measurement.

Conversion to SI Unit: watt per square meter kelvin (W/(m²·K))
1 Btu (th)/(h·ft²·°F) = 5.674467 W/(m²·K)

Joule/second/square meter/K

J/(s·m²·K)
Standard Unit

A Joule/second/square meter/K (J/(s·m²·K)) is a recognized unit for heat transfer coefficient.

Applications & Practical Context

In practical heat transfer coefficient terms, a equivalent to W/(m²·K): Forced water cooling jacket convection equals 2500 J/(s·m²·K).

Physical Setup

A heat transfer coefficient of 1 J/(s·m²·K) yields 1 watt of thermal energy transfer per square meter for each kelvin difference.

Conversion to SI Unit: watt per square meter kelvin (W/(m²·K))
1 J/(s·m²·K) = 1 W/(m²·K)

Domain Metrology & Engineering Applications

Governing Law & Equation

Newton's Law of Cooling (q = h · ΔT)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using surface heat flux transducer plates coupled with surface RTD arrays, and wind tunnel boundary layer calorimeters.

Primary Industry Sectors

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.

Institutional Metrology & Standard Authority:

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].

Multi-Variable Engineering Bridge Convective Thermodynamics & Cooling

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
Vector: [W/(m²·K)] × [K] → [W/m²]
Live Calculated Bridge Equivalent:
1 Btu (th)/(h·ft²·°F) at Forced Air Duct Cooling (ΔT = 25 K) = 141.8617 W/m²
Equals 0.1419 kW/m² • 44.9699 BTU/(h·ft²) • 0.00338831 cal/(s·cm²)
SI Heat Flux
141.8617
W/m²
Watts per Square Meter
Solar / Combustion
0.1419
kW/m²
Kilowatts per Square Meter
US Building Envelope
44.9699
BTU/(h·ft²)
BTU per Hour Sq. Foot
CGS Thermal
0.00338831
cal/(s·cm²)
Calories per Second Sq. Cm
Meteorology
0.2033
Ly/min
Langley per Minute
Furnace Flux
0.00014186
MW/m²
Megawatts per Square Meter
  1. 1. Normalize Input to SI Base Unit (W/(m²·K)):
    h = 1 Btu (th)/(h·ft²·°F) × 5.67446717 = 5.67446717 W/(m²·K)
  2. 2. Apply Engineering Parameter (ΔT):
    Selected condition: Forced Air Duct Cooling (ΔT = 25 K) at ΔT = 25 K
  3. 3. Execute Governing Physical Law in SI Units:
    q" = h × ΔT = (5.67446717 W/(m²·K)) × (25 K) = 141.861679 W/m²
  4. 4. Convert to Standard Engineering Units:
    • W/m²: 141.861679 × 1 = 141.8617 W/m² (Watts per Square Meter) • kW/m²: 141.861679 × 0.001 = 0.1419 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 141.861679 × 0.317 = 44.9699 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 141.861679 × 2.3885 × 10⁻⁵ = 0.00338831 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 141.861679 × 0.001433 = 0.2033 Ly/min (Langley per Minute) • MW/m²: 141.861679 × 1 × 10⁻⁶ = 0.00014186 MW/m² (Megawatts per Square Meter)
Explore Full Heat Flux Density Converter →
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
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Frequently Asked Questions

There are exactly 5.67446717 joules/second/square meter/k (J/(s·m²·K)) in 1 btu (th)/hour/square foot/°f (Btu (th)/(h·ft²·°F)). To calculate larger amounts manually, simply multiply your total number of btus (th)/hour/square foot/°f by the conversion multiplier of 5.67446717.

The mathematical formula to convert btus (th)/hour/square foot/°f to joules/second/square meter/k is: [value] * 5.67446717 = joules/second/square meter/k. Rather than doing the math manually, you can use our high-precision online calculator to process this exact equation instantly without rounding errors.

To perform the reverse calculation from joules/second/square meter/k back to btus (th)/hour/square foot/°f, you must divide your starting value by 5.67446717. Our bidirectional tool automatically computes this inverse equation the moment you type into the joule/second/square meter/k input field.

1 Btu (th)/hour/square foot/°F is larger than 1 Joule/second/square meter/K. Specifically, 1 Btu (th)/hour/square foot/°F equals exactly 5.67446717 joules/second/square meter/k, making it 5.6745 times larger (a difference of 0.75 orders of magnitude). Therefore, quantities expressed in joules/second/square meter/k require a larger numerical value to represent the same physical amount.

Under standard international measurement guidelines, 1 Btu (th)/hour/square foot/°F converts to 5.67446717 joules/second/square meter/k. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.