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What is a british thermal unit?

The US HVAC energy unit — 1055 joules

Definition

The British Thermal Unit equals approximately 1055 joules — the energy to raise 1 pound of water by 1 °F. Used for HVAC, heating, and air-conditioning capacity in the US. A 9000 BTU/h AC is a small room unit.

Common uses

  • US air-conditioner sizing
  • US heating-system capacity
  • Natural gas billing in some US regions

🌍 Real-world scale

Window AC: 5000–12,000 BTU/h. Central AC: 24,000–60,000 BTU/h. Home furnace: 60,000–100,000 BTU/h.

Convert from BTU

9 conversions
British Thermal Unit to Joule1 BTU = 1,055.06 JBritish Thermal Unit to Kilojoule1 BTU = 1.05506 kJBritish Thermal Unit to Megajoule1 BTU = 0.001055 MJBritish Thermal Unit to Kilowatt-Hour1 BTU = 0.0002931 kWhBritish Thermal Unit to Watt-Hour1 BTU = 0.2931 WhBritish Thermal Unit to Calorie1 BTU = 252.164 calBritish Thermal Unit to Kilocalorie1 BTU = 0.2522 kcalBritish Thermal Unit to Electronvolt1 BTU = 6.5851e21 eVBritish Thermal Unit to Therm1 BTU = 1.0000e-5 thm

Convert to BTU

9 conversions
Joule to British Thermal Unit1 J = 0.0009478 BTUKilojoule to British Thermal Unit1 kJ = 0.9478 BTUMegajoule to British Thermal Unit1 MJ = 947.817 BTUKilowatt-Hour to British Thermal Unit1 kWh = 3,412.14 BTUWatt-Hour to British Thermal Unit1 Wh = 3.41214 BTUCalorie to British Thermal Unit1 cal = 0.003966 BTUKilocalorie to British Thermal Unit1 kcal = 3.96567 BTUElectronvolt to British Thermal Unit1 eV = 1.5186e-22 BTUTherm to British Thermal Unit1 thm = 100,000 BTU

Tips

  • 1 BTU = 1055.06 J = 0.293 Wh.
  • BTU/h (power) and BTU (energy) are different — don't confuse.
  • Tons of refrigeration: 12,000 BTU/h = 1 ton AC.

Common mistakes

  • Confusing BTU and BTU/h — energy vs power.
  • Using kcal when BTU is requested in HVAC specs.
  • Treating all BTUs as exact — definitions vary (IT, thermochemical, etc.).

FAQ about the british thermal unit

What is a british thermal unit?
The British Thermal Unit equals approximately 1055 joules — the energy to raise 1 pound of water by 1 °F. Used for HVAC, heating, and air-conditioning capacity in the US. A 9000 BTU/h AC is a small room unit.
Where is the british thermal unit used?
The british thermal unit is commonly used for: US air-conditioner sizing; US heating-system capacity; Natural gas billing in some US regions.
What is an example of a british thermal unit in real life?
Window AC: 5000–12,000 BTU/h. Central AC: 24,000–60,000 BTU/h. Home furnace: 60,000–100,000 BTU/h.
What category does the british thermal unit belong to?
The british thermal unit is a unit of energy, part of the 10-unit energy category on UnitConv.
How accurate are british thermal unit conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
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