What is therm (US)?
A US therm is a unit of energy equal to 100,000 BTU. It is used by gas utility companies in the United States as the standard billing unit for natural gas consumption.
Real-world uses
The therm is used in the United States and United Kingdom for natural gas billing. One therm equals 100,000 BTU (approximately 29.3 kWh). Residential gas bills in the US often list consumption in therms. It is also used in industrial gas metering and procurement contracts.
History
The therm was introduced as a practical unit for natural gas billing in the early 20th century, when gas supply companies needed a convenient large-scale energy unit for residential and commercial customers. It consolidated prior inconsistent measurement practices in the gas industry.
Common mistakes
Confusing the therm with the BTU—1 therm = 100,000 BTU. Also, the US therm and the UK therm differ slightly (the UK therm is based on 105.5 MJ, while the US therm is exactly 100,000 BTU ≈ 105.48 MJ). Not to be confused with the thermie (a metric unit of heat).
What is megajoule?
A megajoule is a unit of energy equal to one million joules. It is used in industrial energy calculations, explosive yield estimations, and large-scale thermodynamic systems.
Real-world uses
Megajoules are used in energy analysis for fuel content (1 litre of petrol contains about 34.2 MJ), building energy ratings, and industrial process energy requirements. Life cycle assessment (LCA) studies report embodied energy in MJ per unit of material.
History
The megajoule became a standard unit in energy engineering and policy analysis during the 20th century. It provides a convenient scale for comparing fuel energy content, industrial processes, and building energy performance across different energy sources.
Common mistakes
Confusing MJ with MWh—1 MWh = 3,600 MJ. Also, when comparing fuel energy densities, failing to distinguish between lower heating value (LHV) and higher heating value (HHV), which can differ by 5–10% for hydrocarbon fuels.
When is this conversion used?
Converting between therm (US) and megajoule is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.
Worked examples
1 therm (US) = 105.506 megajoule
1 megajoule = 1,000,000 joule
How to convert therm (US) to megajoule
To convert therm (US) to megajoule, multiply the value by 105.506.
To convert megajoule back to therm (US), multiply by 0.00947813.
Measurement standards
The joule is the SI derived unit of energy, defined as one kilogram-metre-squared per second-squared (kg·m²/s²). The kilowatt-hour, equal to exactly 3.6 megajoules, is accepted for use with the SI by the BIPM for practical electricity metering.
Did you know?
A single bolt of lightning releases roughly 1 to 5 gigajoules of energy, yet only a small fraction reaches the ground as electrical current. Most of the energy dissipates as light, heat, and the thunder shockwave.
Quick reference: therm (US) to megajoule
| therm (US) | megajoule |
|---|---|
| 0.1 | 10.5506 |
| 0.5 | 52.753 |
| 1 | 105.506 |
| 2 | 211.012 |
| 5 | 527.53 |
| 10 | 1,055.06 |
| 25 | 2,637.65 |
| 50 | 5,275.3 |
| 100 | 10,550.6 |
| 250 | 26,376.5 |
| 500 | 52,753 |
| 1,000 | 105,506 |
Common values
| therm (US) | megajoule | |
|---|---|---|
| A food calorie (1 kcal) | 0.00003966 therm (US) | 0.004184 megajoule |
| A AA battery | 0.00008872 therm (US) | 0.00936 megajoule |
| Boiling a kettle | 0.00398082 therm (US) | 0.42 megajoule |
| Daily human diet (2000 kcal) | 0.07931302 therm (US) | 8.368 megajoule |
| 1 gallon of gasoline | 1.24883893 therm (US) | 131.76 megajoule |
Available Energy units
More therm (US) conversions
- Convert therm (US) to joule
- Convert therm (US) to kilojoule
- Convert therm (US) to kilowatt hour
- Convert therm (US) to calorie (thermochemical)
- Convert therm (US) to kilocalorie (dietary)
- Convert therm (US) to watt hour
- Convert therm (US) to megajoule
- Convert therm (US) to electronvolt
- Convert therm (US) to British thermal unit
Assumption: calorie means thermochemical calorie, and therm means US therm.