Glossary · Energy, bills & ratings
Gigajoule (GJ)
Also called: gigajoules · GJ/year · GJ per year · megajoule · MJ
A metric unit of energy used on some Canadian gas bills and EnerGuide ratings; one GJ equals about 278 kWh, or 25 to 26 cubic metres of natural gas.
What it means
One gigajoule is a billion joules, and a megajoule (MJ) is one-thousandth of a gigajoule. Some Canadian utilities bill natural gas by the GJ and others by cubic metres (m³), and the EnerGuide rating expresses a home's yearly energy use in GJ so different fuels can be added together.
Why it matters in an audit
Your EnerGuide rating and projected savings are reported in GJ, so knowing the conversions lets you translate them into dollars on your bills.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Electricity | 1 GJ = 1,000 MJ ≈ 277.8 kWh | nist.gov ↗ |
| BTU and therms (NRCan factor) | 1 GJ ≈ 947,817 BTU ≈ 9.48 therms | natural-resources.canada.ca ↗ |
| Natural gas volume (Statistics Canada factors) | About 38–39 MJ per m³, so 1 GJ ≈ 25–26 m³ | www150.statcan.gc.ca ↗ |