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BTU per Hour to Joule per Second Converter

Convert BTU/h to J/s with our free online power converter.

Quick Answer

1 BTU per Hour = 0.293071 J/s

Formula: BTU per Hour × conversion factor = Joule per Second

Use the calculator below for instant, accurate conversions.

Our Accuracy Guarantee

All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.

Last verified: December 2025Reviewed by: Sam Mathew, Software Engineer

BTU per Hour to Joule per Second Calculator

How to Use the BTU per Hour to Joule per Second Calculator:

  1. Enter the value you want to convert in the 'From' field (BTU per Hour).
  2. The converted value in Joule per Second will appear automatically in the 'To' field.
  3. Use the dropdown menus to select different units within the Power category.
  4. Click the swap button (⇌) to reverse the conversion direction.
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How to Convert BTU per Hour to Joule per Second: Step-by-Step Guide

Converting BTU per Hour to Joule per Second involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

J/s = BTU/h × 0.293071

Example Calculation:

1 BTU/h = 0.293071 J/s

Disclaimer: For Reference Only

These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.

Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.

Need to convert to other power units?

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What is a BTU per Hour and a Joule per Second?

1 BTU/h = 0.293 W = 0.000293 kW

Key equivalents:

  • 3,412 BTU/h = 1 kW
  • 12,000 BTU/h = 1 ton of refrigeration = 3.52 kW
  • 1 BTU/h = 0.2931 W

1 J/s = 1 W (exactly, by definition)

SI Definition of Watt: 1 W = 1 J/s = 1 kg⋅m²/s³

Note: The BTU per Hour is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Joule per Second belongs to the imperial/US customary system.

Common Uses and Applications: BTU/h vs J/s

Explore the typical applications for both BTU per Hour (imperial/US) and Joule per Second (imperial/US) to understand their common contexts.

Common Uses for BTU/h

Air Conditioning: Window units (5,000-18,000 BTU/h), central systems (18,000-60,000 BTU/h). Furnaces: Home heating (40,000-150,000 BTU/h input). Water Heaters: Gas water heaters (30,000-50,000 BTU/h). HVAC Design: Load calculations, equipment sizing, ductwork design.

When to Use J/s

Physics: Fundamental power unit, teaching energy/power relationship. Engineering: Power calculations, energy transfer rates. Scientific: Research papers, technical specifications. Interchangeable: J/s and W used synonymously.

Additional Unit Information

About BTU per Hour (BTU/h)

How many BTU/h do I need for air conditioning?

Basic calculation: Room square footage × 20-25 BTU/h

Adjustments:

  • Sunny room: Add 10%
  • Shaded room: Subtract 10%
  • Kitchen: Add 4,000 BTU/h
  • More than 2 people: Add 600 BTU/h per person
  • High ceilings (>8 ft): Add 10-20%

Examples:

  • 200 sq ft bedroom: 4,000-5,000 BTU/h (5,000 BTU window unit)
  • 400 sq ft living room: 8,000-10,000 BTU/h (10,000 BTU window unit)
  • 1,500 sq ft home: 30,000-36,000 BTU/h (2.5-3 ton central AC)

[BTU/h calculator for HVAC sizing]

How do I convert BTU/h to watts or kW?

Formula:

  • Watts = BTU/h × 0.293
  • kW = BTU/h ÷ 3,412

Examples:

  • 12,000 BTU/h = 3,517 W = 3.52 kW (1 ton AC)
  • 24,000 BTU/h = 7,034 W = 7.03 kW (2 ton AC)
  • 10,000 BTU/h = 2,930 W = 2.93 kW (window unit)
  • 1,000 BTU/h = 293 W

BTU/h to Watts converter → BTU/h to kW converter →

What is the difference between BTU and BTU/h?

BTU = Energy (total heat/cooling) BTU/h = Power (rate of heating/cooling)

Analogy:

  • BTU = distance traveled (miles)
  • BTU/h = speed (miles per hour)

Example:

  • A 10,000 BTU/h air conditioner removes 10,000 BTU of heat per hour
  • Running for 3 hours removes 30,000 BTU total

Always use BTU/h when rating HVAC equipment capacity!

How many BTU/h equals 1 ton of refrigeration?

1 ton = 12,000 BTU/h = 3.52 kW

Origin: Based on melting 1 ton (2,000 lbs) of ice in 24 hours

Common AC sizes:

  • 1 ton = 12,000 BTU/h (small rooms, ~400-600 sq ft)
  • 1.5 tons = 18,000 BTU/h (larger rooms, ~600-900 sq ft)
  • 2 tons = 24,000 BTU/h (small homes, ~900-1,200 sq ft)
  • 2.5 tons = 30,000 BTU/h (medium homes, ~1,200-1,500 sq ft)
  • 3 tons = 36,000 BTU/h (larger homes, ~1,500-1,800 sq ft)
  • 4 tons = 48,000 BTU/h (large homes, ~2,000-2,400 sq ft)
  • 5 tons = 60,000 BTU/h (very large homes, ~2,400-3,000 sq ft)

BTU/h to Tons converter →

How efficient is my furnace or AC?

Furnace efficiency (AFUE):

  • Old furnace: 60-70% AFUE
  • Standard: 80% AFUE (80,000 BTU/h input → 64,000 BTU/h heat output)
  • High-efficiency: 90-98% AFUE

AC efficiency (SEER):

  • Old AC: SEER 8-10 (inefficient)
  • Standard: SEER 13-14 (minimum new units)
  • High-efficiency: SEER 16-20
  • Ultra-high: SEER 20-26

EER (Energy Efficiency Ratio) = BTU/h output ÷ watts input

  • Good window AC: EER 10-12
  • Excellent: EER 12+

About Joule per Second (J/s)

Why is 1 J/s = 1 W exactly?

SI Definition: The watt is defined as one joule per second

Dimensional analysis:

  • Energy: joules (J)
  • Time: seconds (s)
  • Power: energy/time = J/s

Therefore: 1 W ≡ 1 J/s (definitional equality)

Example: 100W device uses 100 J every second

  • 1 second: 100 J used
  • 10 seconds: 1,000 J used
  • 1 hour (3,600s): 360,000 J = 360 kJ = 0.1 kWh

How do I calculate power from energy and time?

Formula: Power (W or J/s) = Energy (J) ÷ Time (s)

Examples:

Charging phone:

  • Battery capacity: 15 Wh = 54,000 J
  • Charging time: 2 hours = 7,200 s
  • Charging power: 54,000 ÷ 7,200 = 7.5 J/s = 7.5 W

Lifting weight:

  • Work done: 500 J (lifting 50 kg by 1 meter)
  • Time taken: 2 seconds
  • Power output: 500 ÷ 2 = 250 J/s = 250 W

Boiling water:

  • Energy needed: 420,000 J (1 liter, 25°C to 100°C)
  • Time: 6 minutes = 360 s
  • Power: 420,000 ÷ 360 = 1,167 J/s = 1,167 W = 1.17 kW

What is the difference between J/s and J?

J (Joule) = Energy (total amount) J/s (Joule per second) = Power (rate of energy transfer)

Analogy:

  • J = distance traveled (miles)
  • J/s = speed (miles per hour)

Example:

  • Energy stored: 10,000 J (battery capacity)
  • Power delivered: 100 J/s (discharge rate)
  • Time to empty: 10,000 ÷ 100 = 100 seconds

Another example:

  • Microwave energy delivered: 600,000 J (to heat food)
  • Microwave power: 1,000 J/s
  • Cooking time: 600,000 ÷ 1,000 = 600 s = 10 minutes

How do I convert between J/s and other power units?

J/s to watts: 1:1 (they're the same)

J/s to other units:

  • kW = J/s ÷ 1,000
  • hp = J/s ÷ 745.7
  • BTU/h = J/s × 3.412

Examples:

  • 1,000 J/s = 1,000 W = 1 kW
  • 745.7 J/s = 745.7 W = 1 hp
  • 100 J/s = 100 W = 341.2 BTU/h

J/s to kW converter → J/s to HP converter →

Why use W instead of J/s if they're identical?

Brevity: "100 watts" vs "100 joules per second" Convention: Industry standard since 1960 Honor: Named after James Watt (inventor, engineer) Clarity: Distinguishes power from energy (avoids "joules per hour" confusion)

In practice: Both acceptable, but "watt" strongly preferred in all applications. Scientific papers use both interchangeably.

Conversion Table: BTU per Hour to Joule per Second

BTU per Hour (BTU/h)Joule per Second (J/s)
0.50.147
10.293
1.50.44
20.586
51.465
102.931
257.327
5014.654
10029.307
25073.268
500146.536
1,000293.071

People Also Ask

How do I convert BTU per Hour to Joule per Second?

To convert BTU per Hour to Joule per Second, enter the value in BTU per Hour in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our power converter page to convert between other units in this category.

Learn more →

What is the conversion factor from BTU per Hour to Joule per Second?

The conversion factor depends on the specific relationship between BTU per Hour and Joule per Second. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.

Can I convert Joule per Second back to BTU per Hour?

Yes! You can easily convert Joule per Second back to BTU per Hour by using the swap button (⇌) in the calculator above, or by visiting our Joule per Second to BTU per Hour converter page. You can also explore other power conversions on our category page.

Learn more →

What are common uses for BTU per Hour and Joule per Second?

BTU per Hour and Joule per Second are both standard units used in power measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our power converter for more conversion options.

For more power conversion questions, visit our FAQ page or explore our conversion guides.

Helpful Conversion Guides

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📚 How to Convert Units

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🔢 Conversion Formulas

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Verified Against Authority Standards

All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.

NIST Reference on Constants, Units and Uncertainty

National Institute of Standards and Technology — Fundamental physical constants and unit conversions

BIPM SI Units

Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards

ISO 80000

International Organization for Standardization — Quantities and units international standards series

Last verified: December 3, 2025