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Btus (IT)/second/sq. foot/°F to Btus (th)/hour/sq. foot/°F Converter (Btu/(s·ft²·°F) to Btu (th)/(h·ft²·°F))

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Live Conversion • ISO 80000-5:2019 Certified
1 BTU (IT)/second/sq. foot/°F = 3602.40868452 BTU (th)/hour/sq. foot/°F
1 Btu/(s·ft²·°F) = 3602.408685 Btu (th)/(h·ft²·°F) • 1 Btu (th)/(h·ft²·°F) = 0.000277592 Btu/(s·ft²·°F)
BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F: One BTU (IT)/second/sq. foot/°F is equal to 3602.40868452 Btus (th)/hour/sq. foot/°F.
Certified Authority Value
3602.40868452
Btu (th)/(h·ft²·°F)
Exact: 1 Btu (th)/(h·ft²·°F) ≡ 0.0002775920468 Btu/(s·ft²·°F)
Btu/(s·ft²·°F)
Btu/(s·ft²·°F)
Swap to BTU (th)/hour/sq. foot/°F to BTU (IT)/second/sq. foot/°F
Swap to BTU (th)/hour/sq. foot/°F to BTU (IT)/second/sq. foot/°F
Btu (th)/(h·ft²·°F)
Btu (th)/(h·ft²·°F) 3602.40868452
Quick Values:
Conversion Formula
To convert BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F, multiply by 3602.40868452
Btu/(s·ft²·°F) × 3602.40868452 = Btu (th)/(h·ft²·°F)

Calculation: 1 Btu/(s·ft²·°F) × 3602.40868452 = 3602.40868452 Btu (th)/(h·ft²·°F)

Common BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F Calculations

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

Tap any row to calculate
BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F: Primary Direct Table (15 Steps)
BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu/(s·ft²·°F) 3.602409 Btu (th)/(h·ft²·°F) 3.602 × 10⁰
0.01 Btu/(s·ft²·°F) 36.024087 Btu (th)/(h·ft²·°F) 3.602 × 10¹
0.1 Btu/(s·ft²·°F) 360.240868 Btu (th)/(h·ft²·°F) 3.602 × 10²
0.5 Btu/(s·ft²·°F) 1801.204342 Btu (th)/(h·ft²·°F) 1.801 × 10³
1 Btu/(s·ft²·°F) 3602.408685 Btu (th)/(h·ft²·°F) 3.602 × 10³
2 Btu/(s·ft²·°F) 7204.817369 Btu (th)/(h·ft²·°F) 7.205 × 10³
5 Btu/(s·ft²·°F) 18012.043423 Btu (th)/(h·ft²·°F) 1.801 × 10⁴
10 Btu/(s·ft²·°F) 36024.086845 Btu (th)/(h·ft²·°F) 3.602 × 10⁴
20 Btu/(s·ft²·°F) 72048.17369 Btu (th)/(h·ft²·°F) 7.205 × 10⁴
25 Btu/(s·ft²·°F) 90060.217113 Btu (th)/(h·ft²·°F) 9.006 × 10⁴
50 Btu/(s·ft²·°F) 180120.434226 Btu (th)/(h·ft²·°F) 1.801 × 10⁵
100 Btu/(s·ft²·°F) 360240.868452 Btu (th)/(h·ft²·°F) 3.602 × 10⁵
250 Btu/(s·ft²·°F) 900602.171129 Btu (th)/(h·ft²·°F) 9.006 × 10⁵
500 Btu/(s·ft²·°F) 1801204.342258 Btu (th)/(h·ft²·°F) 1.801 × 10⁶
1000 Btu/(s·ft²·°F) 3602408.684517 Btu (th)/(h·ft²·°F) 3.602 × 10⁶
BTU (th)/hour/sq. foot/°F to BTU (IT)/second/sq. foot/°F: Reciprocal Summary
BTU (th)/hour/sq. foot/°F to BTU (IT)/second/sq. foot/°F Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 Btu (th)/(h·ft²·°F) 0.000277592 Btu/(s·ft²·°F) 2.776 × 10⁻⁴
5 Btu (th)/(h·ft²·°F) 0.00138796 Btu/(s·ft²·°F) 1.388 × 10⁻³
10 Btu (th)/(h·ft²·°F) 0.00277592 Btu/(s·ft²·°F) 2.776 × 10⁻³
50 Btu (th)/(h·ft²·°F) 0.0138796 Btu/(s·ft²·°F) 1.388 × 10⁻²
100 Btu (th)/(h·ft²·°F) 0.0277592 Btu/(s·ft²·°F) 2.776 × 10⁻²
View Complete 15-Row BTU (th)/hour/sq. foot/°F to BTU (IT)/second/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)/second/sq. foot/°F (Btu/(s·ft²·°F)) and BTU (th)/hour/sq. foot/°F (Btu (th)/(h·ft²·°F)):

BTU (IT)/second/sq. foot/°F References:

  • Stationary ambient air natural free convection on vertical wall 0.000245 Btu/(s·ft²·°F)
  • Forced air breeze blowing across automotive cooling radiator 0.002446 Btu/(s·ft²·°F)
  • Liquid water forced circulation inside heat exchanger pipe 0.146758 Btu/(s·ft²·°F)
  • Nucleate boiling heat transfer in pressurized steam boiler tube 0.733792 Btu/(s·ft²·°F)

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 BTU (IT)/second/sq. foot/°F to BTU (th)/hour/sq. foot/°F

Converting BTU (IT)/second/sq. foot/°F (Btu/(s·ft²·°F)) 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 BTU (IT)/second/sq. foot/°F equals 3602.408685 BTU (th)/hour/sq. foot/°F, while 1 Btu (th)/(h·ft²·°F) equals 0.000277592 Btu/(s·ft²·°F).

Direct Factor1 Btu/(s·ft²·°F) = 3602.408685 Btu (th)/(h·ft²·°F)
Inverse Ratio1 Btu (th)/(h·ft²·°F) = 0.000277592 Btu/(s·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/(s·ft²·°F) = 20441.748 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 BTU (IT)/second/sq. foot/°F → BTU (th)/hour/sq. foot/°F:V(Btu (th)/(h·ft²·°F)) = V(Btu/(s·ft²·°F)) × ( 20441.748 / 5.674467 ) = V(Btu/(s·ft²·°F)) × 3602.408685
Mathematical FormulaValue in BTU (th)/hour/sq. foot/°F = Value in BTU (IT)/second/sq. foot/°F × 3602.40868452Direct computational formula applied for standard conversion.
Worked Example

Evaluating an input of 120 BTU (IT)/second/sq. foot/°F (Btu/(s·ft²·°F)) produces 432289.042142 BTU (th)/hour/sq. foot/°F (Btu (th)/(h·ft²·°F)). In heavy-duty utility and industrial workloads, 100 Btu/(s·ft²·°F) equals 360240.868452 Btu (th)/(h·ft²·°F).

Inverse check: 1 Btu (th)/(h·ft²·°F) = 0.000277592 Btu/(s·ft²·°F).

Understanding BTU (IT)/second/sq. foot/°F and BTU (th)/hour/sq. foot/°F

BTU (IT)/second/sq. foot/°F

Btu/(s·ft²·°F)
Imperial / US

A BTU (IT)/second/sq. foot/°F (Btu/(s·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 0.000245 Btu/(s·ft²·°F), a forced air breeze blowing across automotive cooling radiator equals 0.002446 Btu/(s·ft²·°F), a liquid water forced circulation inside heat exchanger pipe equals 0.146758 Btu/(s·ft²·°F).

Physical Setup

A physical magnitude of 1 Btu/(s·ft²·°F) corresponds to 20441.748 W/(m²·K) in standard SI measurement.

Conversion to SI Unit: watt per square meter kelvin (W/(m²·K))
1 Btu/(s·ft²·°F) = 20441.748 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 Btu/(s·ft²·°F) at Forced Air Duct Cooling (ΔT = 25 K) = 511043.7 W/m²
Equals 511.0437 kW/m² • 162000.0332 BTU/(h·ft²) • 12.206069 cal/(s·cm²)
SI Heat Flux
511043.7
W/m²
Watts per Square Meter
Solar / Combustion
511.0437
kW/m²
Kilowatts per Square Meter
US Building Envelope
162000.0332
BTU/(h·ft²)
BTU per Hour Sq. Foot
CGS Thermal
12.206069
cal/(s·cm²)
Calories per Second Sq. Cm
Meteorology
732.496
Ly/min
Langley per Minute
Furnace Flux
0.511044
MW/m²
Megawatts per Square Meter
  1. 1. Normalize Input to SI Base Unit (W/(m²·K)):
    h = 1 Btu/(s·ft²·°F) × 20441.748 = 20441.748 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 = (20441.748 W/(m²·K)) × (25 K) = 511043.7 W/m²
  4. 4. Convert to Standard Engineering Units:
    • W/m²: 511043.7 × 1 = 511043.7 W/m² (Watts per Square Meter) • kW/m²: 511043.7 × 0.001 = 511.0437 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 511043.7 × 0.317 = 162000.0332 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 511043.7 × 2.3885 × 10⁻⁵ = 12.206069 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 511043.7 × 0.001433 = 732.496 Ly/min (Langley per Minute) • MW/m²: 511043.7 × 1 × 10⁻⁶ = 0.511044 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 3602.40868452 btus (th)/hour/sq. foot/°f (Btu (th)/(h·ft²·°F)) in 1 btu (it)/second/sq. foot/°f (Btu/(s·ft²·°F)). To calculate larger amounts manually, simply multiply your total number of btus (it)/second/sq. foot/°f by the conversion multiplier of 3602.40868452.

The mathematical formula to convert btus (it)/second/sq. foot/°f to btus (th)/hour/sq. foot/°f is: [value] * 3602.40868452 = 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 btus (it)/second/sq. foot/°f, you must divide your starting value by 3602.40868452. Our bidirectional tool automatically computes this inverse equation the moment you type into the btu (th)/hour/sq. foot/°f input field.

1 BTU (IT)/second/sq. foot/°F is larger than 1 BTU (th)/hour/sq. foot/°F. Specifically, 1 BTU (IT)/second/sq. foot/°F equals exactly 3602.40868452 btus (th)/hour/sq. foot/°f, making it 3602.4087 times larger (a difference of 3.56 orders of magnitude). Therefore, quantities expressed in btus (th)/hour/sq. foot/°f require a larger numerical value to represent the same physical amount.

Under standard international measurement guidelines, 1 BTU (IT)/second/sq. foot/°F converts to 3602.40868452 btus (th)/hour/sq. foot/°f. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.