Why would I ever use this conversion?

Almost never in daily life. This conversion appears in historical energy research, archival work, or academic comparisons of pre-1970s scientific data. If you're not actively reading old physics papers or studying energy history, you won't need it.

What's the 1.054804e+15 factor?

It's the product of two historical conversions: 1 therm = 105.5 megajoules, and 1 joule = 10^7 ergs. So 105.5 × 10^6 × 10^7 = 1.055 × 10^15 ergs per therm. Breaking it into steps makes the huge factor intuitive.

Why are the numbers so large?

Because a therm is enormous in physics terms (100,000 BTU ≈ 105.5 MJ), while an erg is microscopic (10^−7 joules). The ratio is staggering. If you're doing this conversion, you're likely comparing vastly different scales on purpose.

Should I convert to joules or kJ as an intermediate step?

Yes, that's clearer. Convert therms → kilojoules (1 therm = 105,500 kJ), then kilojoules → joules (×1000), then joules → ergs (×10^7). This builds intuition step-by-step instead of using the huge 10^15 factor directly.

Therms (US) to Ergs Converter

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Precision4 dp

1 Therm (US) = 1.0548e+15 Erg

Key Formulas

Kilocalorie → Kilojoule

kJ = kcal × 4.184

Kilojoule → Kilocalorie

kcal = kJ × 0.239006

Kilowatt-Hour → Joule

J = kWh × 3600000

Joule → Kilowatt-Hour

kWh = J × 2.77778e-7

Formula

erg = thm × 1.054804e+15

This is an unusual conversion, needed only in specific historical contexts: comparing natural gas energy content (therms, US billing standard) to scientific data expressed in CGS units (ergs, used pre-1970s). A therm represents 100,000 BTU of natural gas; an erg is the tiny CGS unit of energy. The result is an enormous number (10^15), reflecting the vast difference in scale between a practical natural gas unit and a microscopic physics unit. Most users never encounter this conversion outside specialized energy history or legacy technical comparisons.

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

A historian of US energy policy converts 1 therm (from a 1950s gas bill) to ergs for comparison with physics experiments from that era — 1.05 quadrillion ergs, the scale at which spectroscopy was done.

1 thm = 1054804000000000 erg

An energy archaeologist studying a factory's historical thermostat logs. 10 therms monthly (1950s) = 10.5 quadrillion ergs. Helps contextualize the factory's heat output in contemporary CGS-era literature.

10 thm = 10548040000000000 erg

A university archive digitizing old HVAC engineering manuals from the 1960s. A heating circuit spec of 0.1 therm/hour (105 trillion ergs/hour) helps verify calculations in the original CGS notation.

0.1 thm = 105480400000000 erg

A climate researcher comparing historical winter heating to modern values. A 1960s home burning 100 therms/month (1.05 × 10^17 ergs/month) — a conceptual translation to understand energy scales of that era.

100 thm = 105480400000000000 erg

kcal to kj kj to kcal kwh to joules joules to kwh btu to joules calories to joules

Therms (US) to Ergs Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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