BTU to kWh Converter
Enter energy in British Thermal Units
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Conversion Result
Energy Cost Estimate
Enter energy in kilowatt-hours
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Conversion Result
Energy Cost Estimate
Common Energy Conversions
| BTU | kWh | Common Example | Electric Cost* | Gas Cost** |
|---|---|---|---|---|
| 3,412 BTU | 1 kWh | 1 hour of 1kW appliance | $0.15 | $0.04 |
| 12,000 BTU | 3.52 kWh | 1 ton of AC (1 hour) | $0.53 | $0.14 |
| 100,000 BTU | 29.3 kWh | Small furnace (1 hour) | $4.40 | $1.20 |
| 341,200 BTU | 100 kWh | Average US home (3 days) | $15.00 | $4.00 |
| 1,000,000 BTU | 293 kWh | 1 MMBTU (common gas unit) | $43.95 | $12.00 |
*Based on $0.15/kWh electricity, **Based on $1.20/therm natural gas
How BTU to kWh Conversion Works
Converting between British Thermal Units (BTU) and kilowatt-hours (kWh) is essential for comparing energy from different sources, calculating heating and cooling costs, and understanding energy efficiency across different systems. This conversion bridges the gap between imperial energy measurements (common in HVAC) and metric electrical measurements.
Key Concept: One kilowatt-hour equals exactly 3,412 British Thermal Units. This conversion factor allows you to compare electricity costs with natural gas, heating oil, or other fuel sources on an equal energy basis.
The Conversion Formula
The relationship between BTU and kWh is precise and consistent:
BTU = kWh × 3,412
Where:
- BTU represents energy in British Thermal Units
- kWh represents energy in kilowatt-hours
- 3,412 is the exact conversion factor
Quick Estimate: For rough conversions, use 3,400 as an approximation. To convert BTU to kWh, divide by 3,400. To convert kWh to BTU, multiply by 3,400. This gives a close estimate for most practical purposes: 12,000 BTU ≈ 3.53 kWh (actual: 3.52 kWh).
Understanding Energy Units
| Unit | Equal to | Common Usage | Example |
|---|---|---|---|
| British Thermal Unit (BTU) | 0.000293 kWh 1,055 joules |
US heating/cooling, natural gas | AC units, furnace ratings |
| Kilowatt-hour (kWh) | 3,412 BTU 3.6 megajoules |
Electricity billing globally | Electricity bills, appliance energy |
| Therm | 100,000 BTU 29.3 kWh |
US natural gas billing | Natural gas bills |
| MMBTU (Million BTU) | 1,000,000 BTU 293 kWh |
Industrial energy, large systems | Commercial heating, power plants |
| Megajoule (MJ) | 0.2778 kWh 947.8 BTU |
Scientific, international | Physics, engineering |
Country-Specific Energy Information
United States
The US uses BTU for heating and cooling equipment (air conditioners, furnaces), therm for natural gas billing, and kWh for electricity. Air conditioners are rated in BTU/hour (cooling capacity) while electricity consumption is measured in kWh. Average rates: electricity $0.15/kWh, natural gas $1.20/therm, heating oil $3.50/gallon.
United Kingdom
The UK primarily uses kWh for all energy measurements, including natural gas (converted from cubic meters). BTU is rarely used except for some older heating systems or specialized applications. Average rates: electricity £0.34/kWh ($0.43), natural gas £0.10/kWh ($0.13).
Canada
Canada uses a mix: BTU for HVAC equipment (following US standards), kWh for electricity, and gigajoules (GJ) or cubic meters for natural gas. Electricity rates vary by province: Quebec CA$0.08/kWh, Ontario CA$0.18/kWh. Natural gas is typically CA$0.15-$0.30/m³.
Australia
Australia uses kWh exclusively for all energy measurements. HVAC equipment may show BTU ratings (especially imported units) but local standards use kW for cooling capacity. Electricity rates: AU$0.25-$0.40/kWh ($0.17-$0.27 USD). Natural gas is less common for heating.
Important Note: When comparing fuel costs, consider efficiency. Electric heating is 100% efficient at point of use, but natural gas furnaces are 80-98% efficient. Heat pumps can provide 200-400% efficiency (2-4 kWh of heat per kWh of electricity). Always compare based on useful delivered energy.
Common Applications and Use Cases
HVAC System Sizing and Comparison
Air conditioners are rated in BTU/hour for cooling capacity. To estimate electricity consumption, convert to kW: 12,000 BTU/hr ÷ 3,412 = 3.52 kW. If it runs 8 hours daily: 3.52 kW × 8 hours = 28.16 kWh daily. At $0.15/kWh, that’s $4.22 daily or $126 monthly for cooling alone.
Fuel Cost Comparisons
Comparing heating costs between electricity, natural gas, and heating oil requires converting to common units. Natural gas at $1.20/therm: 1 therm = 100,000 BTU = 29.3 kWh, so $1.20 ÷ 29.3 = $0.041/kWh equivalent. Electricity at $0.15/kWh is 3.7 times more expensive per unit of heat.
Energy Efficiency Calculations
SEER (Seasonal Energy Efficiency Ratio) ratings for air conditioners use BTU/Wh. A 14 SEER unit produces 14 BTU of cooling per Wh of electricity. Convert to COP (Coefficient of Performance): 14 BTU/Wh × (1 Wh ÷ 3.412 BTU) = 4.10 COP, meaning it delivers 4.1 units of cooling per unit of electricity.
Renewable Energy Planning
When sizing solar panels to offset air conditioning, convert BTU cooling needs to kWh electrical requirements. A 24,000 BTU AC running 6 hours daily needs: (24,000 ÷ 3,412) × 6 = 42.2 kWh daily. At 5 peak sun hours, you’d need 8.44 kW of solar panels (42.2 ÷ 5).
Frequently Asked Questions
What’s the difference between BTU and BTU/hour?
BTU measures energy (like gallons of fuel). BTU/hour measures power (like gallons per hour). Air conditioners are rated in BTU/hour for cooling capacity. 12,000 BTU/hour = 1 ton of cooling (historical: melting 1 ton of ice in 24 hours). Electricity consumption depends on how many hours it runs: 12,000 BTU/hour × 8 hours = 96,000 BTU of cooling.
Why 3,412 specifically?
3,412 BTU/kWh comes from the definition: 1 watt = 1 joule/second, so 1 kilowatt-hour = 1,000 watts × 3,600 seconds = 3,600,000 joules. Since 1 BTU = 1,055.06 joules, then 1 kWh = 3,600,000 ÷ 1,055.06 = 3,412.14 BTU. We round to 3,412 for practical use.
How do I calculate my air conditioner’s electricity cost?
Example: 24,000 BTU AC with SEER 16. First, find kW: 24,000 BTU/hr ÷ 3,412 = 7.03 kW cooling capacity. Electrical input: 7.03 kW ÷ (16 ÷ 3.412) = 1.5 kW. If it runs 8 hours at 50% duty cycle: 1.5 kW × 8 hours × 0.5 = 6 kWh daily. At $0.15/kWh: $0.90 daily or $27 monthly.
What’s more efficient: gas furnace or electric heat pump?
Modern gas furnaces: 80-98% efficient (0.8-0.98 units of heat per unit of gas energy). Heat pumps: 200-400% efficient (2-4 units of heat per unit of electricity). Compare costs: Gas at $1.20/therm = $0.041/kWh equivalent. Electricity at $0.15/kWh with heat pump COP 3.0 = $0.05/kWh equivalent. Heat pump is slightly more expensive in this example but varies by location.
Common Mistakes to Avoid
Mistake 1: Confusing BTU with BTU/hour. This is the most common error. BTU measures total energy, BTU/hour measures power (rate). An air conditioner doesn’t use 12,000 BTU of electricity, it uses electricity to move 12,000 BTU/hour of heat.
Mistake 2: Comparing fuel costs without considering efficiency. Natural gas might be cheaper per BTU, but if your furnace is only 80% efficient, you only get 0.8 useful BTU per BTU purchased. Electric resistance heating is 100% efficient at point of use.
Mistake 3: Using wrong conversion for different BTU definitions. There are different BTU definitions (IT, thermochemical, mean). The International Table (IT) BTU (1,055.06 J) is standard for HVAC and energy. Our converter uses this standard 3,412 BTU/kWh conversion.
Practical Examples and Scenarios
Example 1: Air Conditioner Electricity Cost
A 18,000 BTU window AC runs 6 hours daily for 90 days. Convert to kWh: 18,000 BTU/hour ÷ 3,412 = 5.28 kW cooling. With SEER 12 efficiency: 5.28 ÷ (12 ÷ 3.412) = 1.5 kW electrical. Daily use: 1.5 kW × 6 hours = 9 kWh. Seasonal: 9 kWh × 90 days = 810 kWh. Cost: 810 × $0.15 = $121.50 for the cooling season.
Example 2: Comparing Heating Fuels
Heating a home requires 100 million BTU per winter. Options: Natural gas at $1.20/therm (100,000 BTU), heating oil at $3.50/gallon (138,500 BTU), electricity at $0.15/kWh. Convert all to cost per million BTU: Gas: ($1.20 ÷ 0.1) = $12.00/MMBTU. Oil: ($3.50 ÷ 0.1385) = $25.27/MMBTU. Electricity: ($0.15 × 293) = $43.95/MMBTU. Natural gas is cheapest before efficiency adjustments.
Example 3: Solar Panel Sizing for AC
You want solar panels to power a 36,000 BTU central AC. Convert to kW: 36,000 ÷ 3,412 = 10.55 kW cooling. With SEER 16: 10.55 ÷ (16 ÷ 3.412) = 2.25 kW electrical. Running 5 hours daily: 2.25 × 5 = 11.25 kWh daily. With 5 peak sun hours: 11.25 ÷ 5 = 2.25 kW of solar panels needed just for the AC.
Pro Tip: For quick HVAC estimates: 12,000 BTU = 1 ton of cooling ≈ 3.5 kW cooling capacity ≈ 1.0-1.5 kW electrical input (depending on SEER). So a 3-ton AC (36,000 BTU) uses about 3-4.5 kW when running. At $0.15/kWh, that’s $0.45-$0.68 per hour to run.
Historical Context and Modern Usage
The BTU was defined in the late 19th century as the heat required to raise 1 pound of water by 1°F. The kilowatt-hour emerged with electrification as a practical unit for billing electricity consumption. The 3,412 conversion factor has been standardized internationally for energy comparisons.
Today, BTU remains dominant in US HVAC industry, while kWh is the global standard for electricity. With growing focus on energy efficiency and fuel switching (electric vehicles, heat pumps), understanding BTU-kWh conversion is increasingly important for consumers making informed energy decisions.
Why This Converter Is Essential
Our BTU to kWh Converter provides instant, accurate conversions with several key advantages:
- Bidirectional conversion: Convert both BTU to kWh and kWh to BTU
- Cost comparisons: Shows equivalent costs for electricity, natural gas, and heating oil
- Real-world examples: Common HVAC sizes and electricity usage patterns
- Multiple unit outputs: Includes megajoules for scientific reference
- Country-aware defaults: Uses appropriate energy rates for USA, UK, Canada, Australia
- Practical reference table: Common conversions with cost implications
- Instant updates: Results appear as you type
- Educational content: Clear explanations of energy concepts and calculations
- Mobile optimized: Works perfectly on all devices
- No installation needed: Runs directly in your browser
- Completely free: No signup, no fees, no limitations
- Privacy focused: We don’t store or track your conversions
Whether you’re sizing an air conditioner, comparing heating fuels, calculating energy costs, planning renewable energy systems, or studying thermodynamics, this tool provides reliable results instantly. The clear interface and practical examples make it perfect for homeowners, HVAC professionals, energy auditors, students, and anyone who needs to understand energy conversions without unnecessary complexity.