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

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Live Conversion • ISO 80000-5:2019 Certified
1 Joule/second/square meter/K = 0.17622802 BTU (th)/hour/sq. foot/°F
1 J/(s·m²·K) = 0.176228 Btu (th)/(h·ft²·°F) • 1 Btu (th)/(h·ft²·°F) = 5.674467 J/(s·m²·K)
Joule/second/square meter/K to BTU (th)/hour/sq. foot/°F: One Joule/second/square meter/K is equal to 0.17622802 Btus (th)/hour/sq. foot/°F.
Certified Authority Value
0.17622802
Btu (th)/(h·ft²·°F)
Exact: 1 Btu (th)/(h·ft²·°F) ≡ 5.6744666667 J/(s·m²·K)
J/(s·m²·K)
J/(s·m²·K)
Swap to BTU (th)/hour/sq. foot/°F to Joule/second/square meter/K
Swap to BTU (th)/hour/sq. foot/°F to Joule/second/square meter/K
Btu (th)/(h·ft²·°F)
Btu (th)/(h·ft²·°F) 0.17622802
Quick Values:
Conversion Formula
To convert Joule/second/square meter/K to BTU (th)/hour/sq. foot/°F, multiply by 0.17622802
J/(s·m²·K) × 0.17622802 = Btu (th)/(h·ft²·°F)

Calculation: 1 J/(s·m²·K) × 0.17622802 = 0.17622802 Btu (th)/(h·ft²·°F)

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

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

Tap any row to calculate
Joule/second/square meter/K to BTU (th)/hour/sq. foot/°F: Primary Direct Table (15 Steps)
Joule/second/square meter/K to BTU (th)/hour/sq. foot/°F Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 J/(s·m²·K) 0.000176228 Btu (th)/(h·ft²·°F) 1.762 × 10⁻⁴
0.01 J/(s·m²·K) 0.00176228 Btu (th)/(h·ft²·°F) 1.762 × 10⁻³
0.1 J/(s·m²·K) 0.0176228 Btu (th)/(h·ft²·°F) 1.762 × 10⁻²
0.5 J/(s·m²·K) 0.088114 Btu (th)/(h·ft²·°F) 8.811 × 10⁻²
1 J/(s·m²·K) 0.176228 Btu (th)/(h·ft²·°F) 1.762 × 10⁻¹
2 J/(s·m²·K) 0.352456 Btu (th)/(h·ft²·°F) 3.525 × 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
20 J/(s·m²·K) 3.52456 Btu (th)/(h·ft²·°F) 3.525 × 10⁰
25 J/(s·m²·K) 4.4057 Btu (th)/(h·ft²·°F) 4.406 × 10⁰
50 J/(s·m²·K) 8.811401 Btu (th)/(h·ft²·°F) 8.811 × 10⁰
100 J/(s·m²·K) 17.622802 Btu (th)/(h·ft²·°F) 1.762 × 10¹
250 J/(s·m²·K) 44.057004 Btu (th)/(h·ft²·°F) 4.406 × 10¹
500 J/(s·m²·K) 88.114008 Btu (th)/(h·ft²·°F) 8.811 × 10¹
1000 J/(s·m²·K) 176.228016 Btu (th)/(h·ft²·°F) 1.762 × 10²
BTU (th)/hour/sq. foot/°F to Joule/second/square meter/K: Reciprocal Summary
BTU (th)/hour/sq. foot/°F to Joule/second/square meter/K Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 Btu (th)/(h·ft²·°F) 5.674467 J/(s·m²·K) 5.674 × 10⁰
5 Btu (th)/(h·ft²·°F) 28.372333 J/(s·m²·K) 2.837 × 10¹
10 Btu (th)/(h·ft²·°F) 56.744667 J/(s·m²·K) 5.674 × 10¹
50 Btu (th)/(h·ft²·°F) 283.723333 J/(s·m²·K) 2.837 × 10²
100 Btu (th)/(h·ft²·°F) 567.446667 J/(s·m²·K) 5.674 × 10²
View Complete 15-Row BTU (th)/hour/sq. foot/°F to Joule/second/square meter/K 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 Joule/second/square meter/K (J/(s·m²·K)) and BTU (th)/hour/sq. foot/°F (Btu (th)/(h·ft²·°F)):

Joule/second/square meter/K References:

  • Stationary ambient air natural free convection on vertical wall 5 J/(s·m²·K)
  • Forced air breeze blowing across automotive cooling radiator 50 J/(s·m²·K)
  • Liquid water forced circulation inside heat exchanger pipe 3000 J/(s·m²·K)
  • Nucleate boiling heat transfer in pressurized steam boiler tube 15000 J/(s·m²·K)

BTU (th)/hour/sq. foot/°F References:

  • Stationary ambient air natural free convection on vertical wall 0.88114 Btu (th)/(h·ft²·°F)
  • Forced air breeze blowing across automotive cooling radiator 8.8114 Btu (th)/(h·ft²·°F)
  • Liquid water forced circulation inside heat exchanger pipe 528.68 Btu (th)/(h·ft²·°F)
  • Nucleate boiling heat transfer in pressurized steam boiler tube 2643.42 Btu (th)/(h·ft²·°F)

Tap any benchmark above to automatically calculate its exact equivalent in BTU (th)/hour/sq. foot/°F.

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

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

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

Direct Factor1 J/(s·m²·K) = 0.176228 Btu (th)/(h·ft²·°F)
Inverse Ratio1 Btu (th)/(h·ft²·°F) = 5.674467 J/(s·m²·K)
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 J/(s·m²·K) = 1 watt per square meter kelvin (W/(m²·K))
2. Target SI Bridge (ktarget):1 Btu (th)/(h·ft²·°F) = 5.674467 watt per square meter kelvin (W/(m²·K))
Step-by-step substitution for Joule/second/square meter/K → BTU (th)/hour/sq. foot/°F:V(Btu (th)/(h·ft²·°F)) = V(J/(s·m²·K)) × ( 1 / 5.674467 ) = V(J/(s·m²·K)) × 0.176228
Mathematical FormulaValue in BTU (th)/hour/sq. foot/°F = Value in Joule/second/square meter/K × 0.17622802Direct computational formula applied for standard conversion.
Worked Example

To convert 24 Joule/second/square meter/K (J/(s·m²·K)) to BTU (th)/hour/sq. foot/°F (Btu (th)/(h·ft²·°F)): multiply 24 by 0.176228 to get 4.229472 Btu (th)/(h·ft²·°F). At an industrial engineering scale, 1000 J/(s·m²·K) converts to 176.228016 Btu (th)/(h·ft²·°F).

Inverse check: 1 Btu (th)/(h·ft²·°F) = 5.674467 J/(s·m²·K).

Understanding Joule/second/square meter/K and BTU (th)/hour/sq. foot/°F

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 stationary ambient air natural free convection on vertical wall equals 5 J/(s·m²·K), a forced air breeze blowing across automotive cooling radiator equals 50 J/(s·m²·K), a liquid water forced circulation inside heat exchanger pipe equals 3000 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)

BTU (th)/hour/sq. foot/°F

Btu (th)/(h·ft²·°F)
Imperial / US

A BTU (th)/hour/sq. 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 stationary ambient air natural free convection on vertical wall equals 0.88114 Btu (th)/(h·ft²·°F), a forced air breeze blowing across automotive cooling radiator equals 8.8114 Btu (th)/(h·ft²·°F), a liquid water forced circulation inside heat exchanger pipe equals 528.68 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)

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 J/(s·m²·K) at Forced Air Duct Cooling (ΔT = 25 K) = 25 W/m²
Equals 0.025 kW/m² • 7.925 BTU/(h·ft²) • 0.00059711 cal/(s·cm²)
SI Heat Flux
25
W/m²
Watts per Square Meter
Solar / Combustion
0.025
kW/m²
Kilowatts per Square Meter
US Building Envelope
7.925
BTU/(h·ft²)
BTU per Hour Sq. Foot
CGS Thermal
0.00059711
cal/(s·cm²)
Calories per Second Sq. Cm
Meteorology
0.03583
Ly/min
Langley per Minute
Furnace Flux
2.5 × 10⁻⁵
MW/m²
Megawatts per Square Meter
  1. 1. Normalize Input to SI Base Unit (W/(m²·K)):
    h = 1 J/(s·m²·K) × 1 = 1 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 = (1 W/(m²·K)) × (25 K) = 25 W/m²
  4. 4. Convert to Standard Engineering Units:
    • W/m²: 25 × 1 = 25 W/m² (Watts per Square Meter) • kW/m²: 25 × 0.001 = 0.025 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 25 × 0.317 = 7.925 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 25 × 2.3885 × 10⁻⁵ = 0.00059711 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 25 × 0.001433 = 0.03583 Ly/min (Langley per Minute) • MW/m²: 25 × 1 × 10⁻⁶ = 2.5 × 10⁻⁵ 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 0.17622802 btus (th)/hour/sq. foot/°f (Btu (th)/(h·ft²·°F)) in 1 joule/second/square meter/k (J/(s·m²·K)). To calculate larger amounts manually, simply multiply your total number of joules/second/square meter/k by the conversion multiplier of 0.17622802.

The mathematical formula to convert joules/second/square meter/k to btus (th)/hour/sq. foot/°f is: [value] * 0.17622802 = btus (th)/hour/sq. foot/°f. 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 btus (th)/hour/sq. foot/°f back to joules/second/square meter/k, you must divide your starting value by 0.17622802. Our bidirectional tool automatically computes this inverse equation the moment you type into the btu (th)/hour/sq. foot/°f input field.

1 BTU (th)/hour/sq. foot/°F is larger than 1 Joule/second/square meter/K. Specifically, 1 Joule/second/square meter/K equals 0.17622802 btus (th)/hour/sq. foot/°f, meaning 1 BTU (th)/hour/sq. foot/°F is 5.6745 times larger than 1 Joule/second/square meter/K (a difference of 0.75 orders of magnitude). Expressing measurements in joules/second/square meter/k requires a larger numerical value to represent the equivalent physical magnitude.

Under standard international measurement guidelines, 1 Joule/second/square meter/K converts to 0.17622802 btus (th)/hour/sq. foot/°f. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.