Calorific value and state number for gas

In short: A gas meter counts cubic metres. To convert them to kilowatt hours, the provider multiplies by the state number and the calorific value.

In more detail: kWh = consumption in m³ × state number × calorific value. The calorific value (in kWh per m³) says how much energy the gas holds and is usually 10 to 11.5. The state number (about 0.9 to 1.0) converts the volume to standard conditions, because gas has a different density at different pressure and temperature.

Our context: The energy tool has fields for state number and calorific value for gas meters. Both are on your gas bill.

In Depth

• Example: 1,500 m³ × 0.95 × 11.2 kWh/m³ ≈ 15,960 kWh.
• Why the calorific value varies: Gas from different sources has a different composition. The grid operator publishes the value for your area.
• Net calorific value: The net value is lower than the gross value because it does not count the condensation heat of the water vapour. Billing uses the gross value.
• Comparability: Always compare kWh, not m³, when you want to compare gas with other energy sources.

See also: Kilowatt hour (kWh), Advance payments and back payments for electricity and gas