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

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Live Conversion • ISO 80000-5:2019 Certified
1 BTU (IT)/hour/sq. foot/°F = 5.67826333 Joule/second/square meter/K
1 Btu/(h·ft²·°F) = 5.678263 J/(s·m²·K) • 1 J/(s·m²·K) = 0.17611 Btu/(h·ft²·°F)
BTU (IT)/hour/sq. foot/°F to Joule/second/square meter/K: One BTU (IT)/hour/sq. foot/°F is equal to 5.67826333 Joules/second/square meter/K.
Certified Authority Value
5.67826333
J/(s·m²·K)
Exact: 1 J/(s·m²·K) ≡ 0.1761101839 Btu/(h·ft²·°F)
Btu/(h·ft²·°F)
Btu/(h·ft²·°F)
Swap to Joule/second/square meter/K to BTU (IT)/hour/sq. foot/°F
Swap to Joule/second/square meter/K to BTU (IT)/hour/sq. foot/°F
J/(s·m²·K)
J/(s·m²·K) 5.67826333
Quick Values:
Conversion Formula
To convert BTU (IT)/hour/sq. foot/°F to Joule/second/square meter/K, multiply by 5.67826333
Btu/(h·ft²·°F) × 5.67826333 = J/(s·m²·K)

Calculation: 1 Btu/(h·ft²·°F) × 5.67826333 = 5.67826333 J/(s·m²·K)

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

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

Tap any row to calculate
BTU (IT)/hour/sq. foot/°F to Joule/second/square meter/K: Primary Direct Table (15 Steps)
BTU (IT)/hour/sq. foot/°F to Joule/second/square meter/K Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu/(h·ft²·°F) 0.00567826 J/(s·m²·K) 5.678 × 10⁻³
0.01 Btu/(h·ft²·°F) 0.0567826 J/(s·m²·K) 5.678 × 10⁻²
0.1 Btu/(h·ft²·°F) 0.567826 J/(s·m²·K) 5.678 × 10⁻¹
0.5 Btu/(h·ft²·°F) 2.839132 J/(s·m²·K) 2.839 × 10⁰
1 Btu/(h·ft²·°F) 5.678263 J/(s·m²·K) 5.678 × 10⁰
2 Btu/(h·ft²·°F) 11.356527 J/(s·m²·K) 1.136 × 10¹
5 Btu/(h·ft²·°F) 28.391317 J/(s·m²·K) 2.839 × 10¹
10 Btu/(h·ft²·°F) 56.782633 J/(s·m²·K) 5.678 × 10¹
20 Btu/(h·ft²·°F) 113.565267 J/(s·m²·K) 1.136 × 10²
25 Btu/(h·ft²·°F) 141.956583 J/(s·m²·K) 1.42 × 10²
50 Btu/(h·ft²·°F) 283.913167 J/(s·m²·K) 2.839 × 10²
100 Btu/(h·ft²·°F) 567.826333 J/(s·m²·K) 5.678 × 10²
250 Btu/(h·ft²·°F) 1419.565833 J/(s·m²·K) 1.42 × 10³
500 Btu/(h·ft²·°F) 2839.131667 J/(s·m²·K) 2.839 × 10³
1000 Btu/(h·ft²·°F) 5678.263333 J/(s·m²·K) 5.678 × 10³
Joule/second/square meter/K to BTU (IT)/hour/sq. foot/°F: Reciprocal Summary
Joule/second/square meter/K to BTU (IT)/hour/sq. foot/°F Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 J/(s·m²·K) 0.17611 Btu/(h·ft²·°F) 1.761 × 10⁻¹
5 J/(s·m²·K) 0.880551 Btu/(h·ft²·°F) 8.806 × 10⁻¹
10 J/(s·m²·K) 1.761102 Btu/(h·ft²·°F) 1.761 × 10⁰
50 J/(s·m²·K) 8.805509 Btu/(h·ft²·°F) 8.806 × 10⁰
100 J/(s·m²·K) 17.611018 Btu/(h·ft²·°F) 1.761 × 10¹
View Complete 15-Row Joule/second/square meter/K to BTU (IT)/hour/sq. 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 (IT)/hour/sq. foot/°F (Btu/(h·ft²·°F)) and Joule/second/square meter/K (J/(s·m²·K)):

BTU (IT)/hour/sq. foot/°F References:

  • Stationary ambient air natural free convection on vertical wall 0.880551 Btu/(h·ft²·°F)
  • Forced air breeze blowing across automotive cooling radiator 8.8055 Btu/(h·ft²·°F)
  • Liquid water forced circulation inside heat exchanger pipe 528.33 Btu/(h·ft²·°F)
  • Nucleate boiling heat transfer in pressurized steam boiler tube 2641.65 Btu/(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)

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 (IT)/hour/sq. foot/°F to Joule/second/square meter/K

Converting BTU (IT)/hour/sq. foot/°F (Btu/(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 (IT)/hour/sq. foot/°F equals 5.678263 Joule/second/square meter/K, while 1 J/(s·m²·K) equals 0.17611 Btu/(h·ft²·°F).

Direct Factor1 Btu/(h·ft²·°F) = 5.678263 J/(s·m²·K)
Inverse Ratio1 J/(s·m²·K) = 0.17611 Btu/(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/(h·ft²·°F) = 5.678263 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 (IT)/hour/sq. foot/°F → Joule/second/square meter/K:V(J/(s·m²·K)) = V(Btu/(h·ft²·°F)) × ( 5.678263 / 1 ) = V(Btu/(h·ft²·°F)) × 5.678263
Mathematical FormulaValue in Joule/second/square meter/K = Value in BTU (IT)/hour/sq. foot/°F × 5.67826333Direct computational formula applied for standard conversion.
Worked Example

To convert 2.5 BTU (IT)/hour/sq. foot/°F (Btu/(h·ft²·°F)) to Joule/second/square meter/K (J/(s·m²·K)): multiply 2.5 by 5.678263 to get 14.195658 J/(s·m²·K). At an industrial engineering scale, 240 Btu/(h·ft²·°F) converts to 1362.7832 J/(s·m²·K).

Inverse check: 1 J/(s·m²·K) = 0.17611 Btu/(h·ft²·°F).

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

BTU (IT)/hour/sq. foot/°F

Btu/(h·ft²·°F)
Imperial / US

A BTU (IT)/hour/sq. 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 stationary ambient air natural free convection on vertical wall equals 0.880551 Btu/(h·ft²·°F), a forced air breeze blowing across automotive cooling radiator equals 8.8055 Btu/(h·ft²·°F), a liquid water forced circulation inside heat exchanger pipe equals 528.33 Btu/(h·ft²·°F).

Physical Setup

A physical magnitude of 1 Btu/(h·ft²·°F) corresponds to 5.678263 W/(m²·K) in standard SI measurement.

Conversion to SI Unit: watt per square meter kelvin (W/(m²·K))
1 Btu/(h·ft²·°F) = 5.678263 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 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)

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/(h·ft²·°F) at Forced Air Duct Cooling (ΔT = 25 K) = 141.9566 W/m²
Equals 0.142 kW/m² • 45 BTU/(h·ft²) • 0.00339057 cal/(s·cm²)
SI Heat Flux
141.9566
W/m²
Watts per Square Meter
Solar / Combustion
0.142
kW/m²
Kilowatts per Square Meter
US Building Envelope
45
BTU/(h·ft²)
BTU per Hour Sq. Foot
CGS Thermal
0.00339057
cal/(s·cm²)
Calories per Second Sq. Cm
Meteorology
0.2035
Ly/min
Langley per Minute
Furnace Flux
0.00014196
MW/m²
Megawatts per Square Meter
  1. 1. Normalize Input to SI Base Unit (W/(m²·K)):
    h = 1 Btu/(h·ft²·°F) × 5.67826333 = 5.67826333 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 = (5.67826333 W/(m²·K)) × (25 K) = 141.956583 W/m²
  4. 4. Convert to Standard Engineering Units:
    • W/m²: 141.956583 × 1 = 141.9566 W/m² (Watts per Square Meter) • kW/m²: 141.956583 × 0.001 = 0.142 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 141.956583 × 0.317 = 45 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 141.956583 × 2.3885 × 10⁻⁵ = 0.00339057 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 141.956583 × 0.001433 = 0.2035 Ly/min (Langley per Minute) • MW/m²: 141.956583 × 1 × 10⁻⁶ = 0.00014196 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 5.67826333 joules/second/square meter/k (J/(s·m²·K)) in 1 btu (it)/hour/sq. foot/°f (Btu/(h·ft²·°F)). To calculate larger amounts manually, simply multiply your total number of btus (it)/hour/sq. foot/°f by the conversion multiplier of 5.67826333.

The mathematical formula to convert btus (it)/hour/sq. foot/°f to joules/second/square meter/k is: [value] * 5.67826333 = 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 (it)/hour/sq. foot/°f, you must divide your starting value by 5.67826333. Our bidirectional tool automatically computes this inverse equation the moment you type into the joule/second/square meter/k input field.

1 BTU (IT)/hour/sq. foot/°F is larger than 1 Joule/second/square meter/K. Specifically, 1 BTU (IT)/hour/sq. foot/°F equals exactly 5.67826333 joules/second/square meter/k, making it 5.6783 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 (IT)/hour/sq. foot/°F converts to 5.67826333 joules/second/square meter/k. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.