Understanding Ergs to US Therms Conversion
The erg is the CGS unit of energy, and the US therm is a natural-gas energy unit equal to 100,000 British thermal units, or about 1.054804 \times 10⁸ joules. Therms appear on US gas utility bills. This conversion connects fundamental CGS energies with the US therm used to meter and price natural gas for heating and cooking.
Conversion Formula
To convert Ergs to US Therms, multiply by this factor:
Step-by-Step Example
Convert 25 Ergs to US Therms.
How to Convert Ergs to US Therms
Converting ergs to US therms expresses a CGS energy in natural-gas billing units.
- Record the erg value: Identify the energy in ergs.
- Multiply by the factor: Multiply by 9.48043 \times 10⁻¹⁶ therms per erg.
- Read the answer: 25 erg equals 2.37011 \times 10⁻¹⁴ therms.
Ergs to US Therms conversion table
| Ergs (erg) | US Therms (thm) |
|---|---|
| 0 | 0 |
| 1 | 9.480434e-16 |
| 2 | 1.896087e-15 |
| 3 | 2.84413e-15 |
| 4 | 3.792174e-15 |
| 5 | 4.740217e-15 |
| 6 | 5.688261e-15 |
| 7 | 6.636304e-15 |
| 8 | 7.584347e-15 |
| 9 | 8.532391e-15 |
| 10 | 9.480434e-15 |
| 15 | 1.422065e-14 |
| 20 | 1.896087e-14 |
| 25 | 2.370109e-14 |
| 30 | 2.84413e-14 |
| 40 | 3.792174e-14 |
| 50 | 4.740217e-14 |
| 60 | 5.688261e-14 |
| 70 | 6.636304e-14 |
| 80 | 7.584347e-14 |
| 90 | 8.532391e-14 |
| 100 | 9.480434e-14 |
| 150 | 1.422065e-13 |
| 200 | 1.896087e-13 |
| 250 | 2.370109e-13 |
| 300 | 2.84413e-13 |
| 400 | 3.792174e-13 |
| 500 | 4.740217e-13 |
| 600 | 5.688261e-13 |
| 700 | 6.636304e-13 |
| 800 | 7.584347e-13 |
| 900 | 8.532391e-13 |
| 1000 | 9.480434e-13 |
| 2000 | 1.896087e-12 |
| 3000 | 2.84413e-12 |
| 4000 | 3.792174e-12 |
| 5000 | 4.740217e-12 |
| 10000 | 9.480434e-12 |
| 25000 | 2.370109e-11 |
| 50000 | 4.740217e-11 |
| 100000 | 9.480434e-11 |
| 250000 | 2.370109e-10 |
| 500000 | 4.740217e-10 |
| 1000000 | 9.480434e-10 |
What is the Erg?
The erg is a unit of energy in the centimetre-gram-second (CGS) system, historically common in physics, astronomy, and mechanics before the SI joule became standard.
Definition
One erg is the work done by a force of one dyne acting over a distance of one centimetre:
This equals exactly one ten-millionth of a joule (10⁻⁷ J), or equivalently 1 g·cm²/s². The erg is a small unit, reflecting the small base units of the CGS system.
Origin and History
The name comes from the Greek ergon, meaning "work." The unit was formally adopted by the British Association for the Advancement of Science in 1873 as part of the CGS system and remained the dominant energy unit in physics literature well into the 20th century.
Law and Notable Facts
The erg has been largely superseded by the joule and is deprecated in the modern SI framework, but it persists in astrophysics, where luminosities and energies are still frequently quoted in ergs and erg per second.
Real-World Examples and Conversions
- 1 joule equals 10 million ergs.
- A mosquito in flight expends energy on the order of a few ergs per wingbeat.
- The Sun radiates about 3.8 × 10³³ ergs every second, equivalent to 3.8 × 10²⁶ watts.
What is the US Therm?
The US therm is a unit of heat energy used primarily in the natural gas industry to measure and bill the energy content of gas supplied to homes and businesses in the United States.
Definition
The US therm is defined as 100,000 British thermal units (BTU) based on the 59 °F (15 °C) BTU:
More precisely, the US therm equals exactly 105,480,400 joules (about 105.48 MJ). It should not be confused with the slightly larger UK therm, which is based on the International Table BTU and equals 105,505,585.257 J.
Origin and History
The therm entered use in the 20th century as gas utilities shifted from billing customers by volume to billing by delivered energy, since the heating value of natural gas varies with its composition. Combining "therm" (from the Greek thermē, heat) with a fixed BTU count gave a convenient billing unit roughly equal to the energy in 100 cubic feet of typical natural gas.
Law and Notable Facts
In the United States the therm is a legally recognized commercial unit for natural gas sales. Gas meters record volume in hundreds of cubic feet (ccf), which utilities multiply by a "therm factor" reflecting the gas's actual heat content to convert to therms for billing.
Real-World Examples and Conversions
- A typical US home uses roughly 500 to 1,000 therms of natural gas per year for heating, cooking, and hot water.
- 1 therm equals about 29.3 kilowatt-hours of energy.
- Burning 1 therm of natural gas releases approximately 105.5 MJ of heat, enough to run a 20 kW furnace at full output for about 88 minutes.
Frequently Asked Questions
How many US therms is one erg?
One erg equals 9.48043 \times 10⁻¹⁶ therms.
How many ergs are in a US therm?
One US therm equals 1.054804 \times 10¹⁵ ergs.
What is a therm equal to?
A US therm is 100,000 BTU, roughly 1.054804 \times 10⁸ joules.
Where is the therm used?
It is the billing unit for natural gas on US utility statements.
What is 25 ergs in US therms?
25 erg equals 2.37011 \times 10⁻¹⁴ therms.
People also convert
Complete Ergs conversion table
| Unit | Result |
|---|---|
| Watt-seconds (Ws) | 1e-7 Ws |
| Watt-minutes (Wm) | 1.666667e-9 Wm |
| Watt-hours (Wh) | 2.777778e-11 Wh |
| Milliwatt-hours (mWh) | 2.777778e-8 mWh |
| Kilowatt-hours (kWh) | 2.777778e-14 kWh |
| Megawatt-hours (MWh) | 2.777778e-17 MWh |
| Gigawatt-hours (GWh) | 2.777778e-20 GWh |
| Joules (J) | 1e-7 J |
| Kilojoules (kJ) | 1e-10 kJ |
| Megajoules (MJ) | 1e-13 MJ |
| Gigajoules (GJ) | 1e-16 GJ |
| British Thermal Units (IT) (BTU) | 9.478171e-11 BTU |
| US Therms (thm) | 9.480434e-16 thm |
| Electronvolts (eV) | 624150900000 eV |
| Foot-pounds (ft-lbf) | 7.375621e-8 ft-lbf |
| Tonnes of TNT (t-tnt) | 2.390057e-17 t-tnt |
| calories (cal) | 2.390057e-8 cal |
| Kilocalories (kcal) | 2.390057e-11 kcal |