However, the BTU is not standardised worldwide, with slightly different values in the EU, UK, and United States, meaning that the energy content of the therm also varies by territory.
Higher than average concentration of ethane, propane or butane will increase the therm factor and the inclusion of non-flammable impurities, such as carbon dioxide or nitrogen will reduce it.
The energy content of 1,000 cubic feet (28 m3) natural gas measured at standard conditions is approximately equal to one dekatherm.
The Federal Power Commission issued an order approving the settlement agreement and the new tariff using dekatherms later that year,[10] Other gas distribution companies also began to use this process.
[11] In spite of the need for adjustments, many companies continue to use standard cubic feet rather than dekatherms to measure and bill natural gas.