For newer gas meters, the quantity of natural gas is usually expressed in cubic meters (m³). If you want to know how much electricity will burning gas generate, you have to convert gas m³ into kWh (kilowatt-hours). Converting gas units to kWh is useful for comparing the gas energy usage to that of the electricity.

The key thing to remember is that 1 m³ of natural gas doesn’t always generate the same amount of electricity (kWh). That’s because the energy density of natural gas varies a bit depending on the quality of natural gas (some produce more kWh, others less kWh).

If you quickly want to convert m³ to kWh, you just need to use this simple formula without losing too much accuracy:

1 m³ = 10.55 kWh

m³ to kWh Conversion Formula

The formula above works well when doing speedy or rough calculations. However, the Pilio software uses a bit more complex equation to convert m³ to kWh, precisely:

m³ × Calorific Value × 1.02264 ÷ 3.6 = kWh

• The Calorific Value is a multiplier indicating how many kWh of energy is obtained from one cubic meter of gas. In the GB network, it is measured each day and can vary from day to day and between different areas of the gas network. However, this is usually around 40 in GB and, depending on the quality of natural gas, it can deviate +/-5%. Pilio uses 39.5 as a Calorific Value as suggested by the National Grid.

• 1.02264 is a correction factor, and 3.6 is the conversion factor for kWh.

Meters with imperial units (e.g. ft³)

Some older meters use imperial units (e.g. ft³, 100ft³ etc.). To calculate the associated kWh, the imperial unit is first converted to m³ and then to kWh by applying the formula above.

To covert 1 cubic foot to cubic meters, multiply the cubic foot value by 0.0283168466 or divide by 35.3146667.

To convert cubic feet to kWh, Pilio uses the below formulas:

1 ft³ x 0.0283168466 × Calorific Value × 1.02264 ÷ 3.6 = kWh

Gas therms

A therm is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU). It is approximately the energy content of 100 cubic feet (2.83 cubic metres) – often referred to as 1 CCF – of natural gas at standard temperature and pressure. As there are differing definitions of the BTU in use around the world, there are various slightly differing values for the energy content of the therm.

Pilio uses the below formulas when calculating the associated kWh:

Therm (EC) x 29.3072 = kWh

Therm (US) x 29.3 = kWh

Therm (UK) x 29.307 = kWh

Gas gigajoules

Since one gigajoule is equal to 277.777778 kilowatt-hours, we calculate the associated kWh by doing:

Gigajoules × 277.777778 = kWh

Why are my kWh results different from billed consumption?

As stated above for meters in ft3 or m3, the Calorific Value is the only parameter that changes. Different gas suppliers have different Calorific Values. Also, this value can change as often as every month. Your supplier's calorific value is usually stated in their bills.

While we currently offer no option to upload your custom Calorific Value, if you would like to import gas kWh into Pilio, you can!

When setting up a gas meter, make sure to select 'kWh' as the unit and 'consumption data' for 'Import consumption or half-hourly data'.

Doing so has both advantages and disadvantages:

• advantages: your results are 100% accurate to your supplier's stated consumption.

• disadvantages:

- the Calorific Value can change every month, which means that you'll need to add to Pilio this information every month,

- you are not registering meter readings but consumption data (i.e. you cannot use this to store meter readings that your supplier might ask for),

- if you will receive a gas rebill or credit notice, you'll have to manually change the previously imported kWh so as to reflect your recalculations.