Glossary · Energy, bills & ratings
Therm
Also called: therms · thm · dekatherm · dekatherms · Dth
The unit many US gas bills use: one therm is 100,000 BTU of heat energy, roughly the energy in 100 cubic feet of natural gas.
What it means
Utilities convert the gas volume your meter records, often in hundreds of cubic feet (CCF), into therms using the gas's heat content. A dekatherm is 10 therms. To compare with electricity, 1 therm is about 29.3 kWh.
Why it matters in an audit
Your yearly therms for heating, compared with heating degree days, let an auditor estimate how much air sealing, insulation or new equipment would save.
Typical numbers
Reference values with their sources. Your auditor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Definition (EIA) | 1 therm = 100,000 BTU | eia.gov ↗ |
| Metric (NIST) | 1 therm = 105.5 MJ ≈ 0.1055 GJ | nist.gov ↗ |
| Gas volume (EIA factor) | 100 cubic feet ≈ 1.036 therms (1,036 BTU per cubic foot) | eia.gov ↗ |
| Electric equivalent | ≈ 29.3 kWh | Arithmetic from EIA factors |