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Horsepowers/square foot to Btus (th)/second/sq. foot Converter (hp/ft² to Btu/(s·ft²))

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Live Conversion • ISO 80000-5:2019 Certified
1 Horsepower/square foot = 0.70726024 BTU (th)/second/sq. foot
1 hp/ft² = 0.70726 Btu/(s·ft²) • 1 Btu/(s·ft²) = 1.413907 hp/ft²
Horsepower/square foot to BTU (th)/second/sq. foot: One Horsepower/square foot is equal to 0.70726024 Btus (th)/second/sq. foot.
Certified Authority Value
0.70726024
Btu/(s·ft²)
Exact: 1 Btu/(s·ft²) ≡ 1.4139067035 hp/ft²
hp/ft²
hp/ft²
Swap to BTU (th)/second/sq. foot to Horsepower/square foot
Swap to BTU (th)/second/sq. foot to Horsepower/square foot
Btu/(s·ft²)
Btu/(s·ft²) 0.70726024
Quick Values:
Conversion Formula
To convert Horsepower/square foot to BTU (th)/second/sq. foot, multiply by 0.70726024
hp/ft² × 0.70726024 = Btu/(s·ft²)

Calculation: 1 hp/ft² × 0.70726024 = 0.70726024 Btu/(s·ft²)

Common Horsepower/square foot to BTU (th)/second/sq. foot Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between Horsepower/square foot (hp/ft²) and BTU (th)/second/sq. foot (Btu/(s·ft²)).

Tap any row to calculate
Horsepower/square foot to BTU (th)/second/sq. foot: Primary Direct Table (15 Steps)
Horsepower/square foot to BTU (th)/second/sq. foot Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 hp/ft² 0.00070726 Btu/(s·ft²) 7.073 × 10⁻⁴
0.01 hp/ft² 0.0070726 Btu/(s·ft²) 7.073 × 10⁻³
0.1 hp/ft² 0.070726 Btu/(s·ft²) 7.073 × 10⁻²
0.5 hp/ft² 0.35363 Btu/(s·ft²) 3.536 × 10⁻¹
1 hp/ft² 0.70726 Btu/(s·ft²) 7.073 × 10⁻¹
2 hp/ft² 1.41452 Btu/(s·ft²) 1.415 × 10⁰
5 hp/ft² 3.536301 Btu/(s·ft²) 3.536 × 10⁰
10 hp/ft² 7.072602 Btu/(s·ft²) 7.073 × 10⁰
20 hp/ft² 14.145205 Btu/(s·ft²) 1.415 × 10¹
25 hp/ft² 17.681506 Btu/(s·ft²) 1.768 × 10¹
50 hp/ft² 35.363012 Btu/(s·ft²) 3.536 × 10¹
100 hp/ft² 70.726024 Btu/(s·ft²) 7.073 × 10¹
250 hp/ft² 176.815061 Btu/(s·ft²) 1.768 × 10²
500 hp/ft² 353.630122 Btu/(s·ft²) 3.536 × 10²
1000 hp/ft² 707.260244 Btu/(s·ft²) 7.073 × 10²
BTU (th)/second/sq. foot to Horsepower/square foot: Reciprocal Summary
BTU (th)/second/sq. foot to Horsepower/square foot Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 Btu/(s·ft²) 1.413907 hp/ft² 1.414 × 10⁰
5 Btu/(s·ft²) 7.069534 hp/ft² 7.07 × 10⁰
10 Btu/(s·ft²) 14.139067 hp/ft² 1.414 × 10¹
50 Btu/(s·ft²) 70.695335 hp/ft² 7.07 × 10¹
100 Btu/(s·ft²) 141.39067 hp/ft² 1.414 × 10²
View Complete 15-Row BTU (th)/second/sq. foot to Horsepower/square foot 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 Horsepower/square foot (hp/ft²) and BTU (th)/second/sq. foot (Btu/(s·ft²)):

Horsepower/square foot References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 0.16956 hp/ft²
  • Clear sky direct midday summer sunlight striking sea level ground 0.124585 hp/ft²
  • Human body resting thermal metabolic heat radiation to room 0.006229 hp/ft²
  • Overcast winter day diffuse solar irradiance at sea level 0.012459 hp/ft²

BTU (th)/second/sq. foot References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 0.119923 Btu/(s·ft²)
  • Clear sky direct midday summer sunlight striking sea level ground 0.088114 Btu/(s·ft²)
  • Human body resting thermal metabolic heat radiation to room 0.004406 Btu/(s·ft²)
  • Overcast winter day diffuse solar irradiance at sea level 0.008811 Btu/(s·ft²)

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

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

How to Convert Horsepower/square foot to BTU (th)/second/sq. foot

Converting Horsepower/square foot (hp/ft²) to BTU (th)/second/sq. foot (Btu/(s·ft²)) is a core calculation in Heat Flux Density, which measures the rate of thermal energy transfer radiating or conducting through a unit area per second. 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 Horsepower/square foot equals 0.70726 BTU (th)/second/sq. foot, while 1 Btu/(s·ft²) equals 1.413907 hp/ft².

Direct Factor1 hp/ft² = 0.70726 Btu/(s·ft²)
Inverse Ratio1 Btu/(s·ft²) = 1.413907 hp/ft²
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 (W/m²)) 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 hp/ft² = 8026.647 watt per square meter (W/m²)
2. Target SI Bridge (ktarget):1 Btu/(s·ft²) = 11348.93 watt per square meter (W/m²)
Step-by-step substitution for Horsepower/square foot → BTU (th)/second/sq. foot:V(Btu/(s·ft²)) = V(hp/ft²) × ( 8026.647 / 11348.93 ) = V(hp/ft²) × 0.70726
Mathematical FormulaValue in BTU (th)/second/sq. foot = Value in Horsepower/square foot × 0.70726024Direct computational formula applied for standard conversion.
Worked Example

To convert 120 Horsepower/square foot (hp/ft²) to BTU (th)/second/sq. foot (Btu/(s·ft²)): multiply 120 by 0.70726 to get 84.871229 Btu/(s·ft²). At an industrial engineering scale, 2500 hp/ft² converts to 1768.15061 Btu/(s·ft²).

Inverse check: 1 Btu/(s·ft²) = 1.413907 hp/ft².

Understanding Horsepower/square foot and BTU (th)/second/sq. foot

Horsepower/square foot

hp/ft²
Imperial / US

A Horsepower/square foot (hp/ft²) is an imperial and US customary unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 0.16956 hp/ft², a clear sky direct midday summer sunlight striking sea level ground equals 0.124585 hp/ft², a human body resting thermal metabolic heat radiation to room equals 0.006229 hp/ft².

Physical Setup

A physical magnitude of 1 hp/ft² corresponds to 8026.647 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 hp/ft² = 8026.647 W/m²

BTU (th)/second/sq. foot

Btu/(s·ft²)
Imperial / US

A BTU (th)/second/sq. foot (Btu/(s·ft²)) is an imperial and US customary unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 0.119923 Btu/(s·ft²), a clear sky direct midday summer sunlight striking sea level ground equals 0.088114 Btu/(s·ft²), a human body resting thermal metabolic heat radiation to room equals 0.004406 Btu/(s·ft²).

Physical Setup

A physical magnitude of 1 Btu/(s·ft²) corresponds to 11348.93 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 Btu/(s·ft²) = 11348.93 W/m²

Domain Metrology & Engineering Applications

Governing Law & Equation

Thermal Transmission Flux (q = Q̇ / A)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using Schmidt-Boelter heat flux gauges, differential thermopile foil transducers, and calibrated Gardon radiant gauges.

Primary Industry Sectors

Applied across rocket nozzle combustion chamber analysis, fire resistance testing (ASTM E119), furnace wall heat loss auditing, and hypersonic aerothermal design under international metrology standard ISO 80000-5:2019, ASME PTC 19.3.

Institutional Metrology & Standard Authority:

Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-5:2019, ASME PTC 19.3 and the BIPM SI Brochure (9th Edition). Governed by Thermal Transmission Flux (q = Q̇ / A) under ISO 80000 dimensional vector [M T⁻³].

Multi-Variable Engineering Bridge Thermal Radiation & Power Dissipation

Heat Flux Density to Total Thermal Power Bridge (Watts • Kilowatts • Megawatts • BTU/h • Horsepower)

Calculate total continuous heat dissipation power P = q" × A across surface barriers and exchangers, bridging heat flux density [M T⁻³] with thermal power [M L² T⁻³].

P = q" × A
Vector: [W/m²] × [m²] → [W]
Live Calculated Bridge Equivalent:
1 hp/ft² at Industrial Hydronic Radiator Panel (8 m²) = 64213.176 W
Equals 64.2132 kW • 0.0642132 MW • 86.1113 hp
SI Power
64213.176
W
Watts
Grid / Utility
64.2132
kW
Kilowatts
Power Plant
0.0642132
MW
Megawatts
Mechanical Rating
86.1113
hp
Horsepower (Mechanical)
Metric Horsepower
87.3056
PS
Metric Horsepower (PS)
HVAC Thermal Rating
219104.45
BTU/h
BTU per Hour
  1. 1. Normalize Input to SI Base Unit (W/m²):
    q" = 1 hp/ft² × 8026.647 = 8026.647 W/m²
  2. 2. Apply Engineering Parameter (A):
    Selected condition: Industrial Hydronic Radiator Panel (8 m²) at A = 8 m²
  3. 3. Execute Governing Physical Law in SI Units:
    P = q" × A = (8026.647 W/m²) × (8 m²) = 64213.176 W
  4. 4. Convert to Standard Engineering Units:
    • W: 64213.176 × 1 = 64213.176 W (Watts) • kW: 64213.176 × 0.001 = 64.2132 kW (Kilowatts) • MW: 64213.176 × 1 × 10⁻⁶ = 0.0642132 MW (Megawatts) • hp: 64213.176 × 0.001341 = 86.1113 hp (Horsepower (Mechanical)) • PS: 64213.176 × 0.00136 = 87.3056 PS (Metric Horsepower (PS)) • BTU/h: 64213.176 × 3.4121 = 219104.45 BTU/h (BTU per Hour)
Explore Full Power Converter →
Engineering Substance / Operating Standard Parameter Value (m²) Reference State / Condition Typical Industrial & Engineering Application
Residential Window Glazing (4 m²) 4 4.0 m² Double-pane exterior window glass aperture
Industrial Hydronic Radiator Panel (8 m²) 8 8.0 m² Convective space heating radiator surface
Shell & Tube Heat Exchanger (50 m²) 50 50.0 m² Industrial process fluid cooling bundle
Power Boiler Waterwall (200 m²) 200 200.0 m² Thermal power plant steam generator wall
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Frequently Asked Questions

There are exactly 0.70726024 btus (th)/second/sq. foot (Btu/(s·ft²)) in 1 horsepower/square foot (hp/ft²). To calculate larger amounts manually, simply multiply your total number of horsepowers/square foot by the conversion multiplier of 0.70726024.

The mathematical formula to convert horsepowers/square foot to btus (th)/second/sq. foot is: [value] * 0.70726024 = btus (th)/second/sq. foot. 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)/second/sq. foot back to horsepowers/square foot, you must divide your starting value by 0.70726024. Our bidirectional tool automatically computes this inverse equation the moment you type into the btu (th)/second/sq. foot input field.

1 BTU (th)/second/sq. foot is larger than 1 Horsepower/square foot. Specifically, 1 Horsepower/square foot equals 0.70726024 btus (th)/second/sq. foot, meaning 1 BTU (th)/second/sq. foot is 1.4139 times larger than 1 Horsepower/square foot (a difference of 0.15 orders of magnitude). Expressing measurements in horsepowers/square foot requires a larger numerical value to represent the equivalent physical magnitude.

Under standard international measurement guidelines, 1 Horsepower/square foot converts to 0.70726024 btus (th)/second/sq. foot. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.