Water Heater Energy Factor, Pippin Brothers, Lawton, OK
August 27, 2014

Energy factor (EF) rating is like the Miles Per Gallon (MPG) of water heaters. It determines how efficiently the water heater uses its fuel source.

For example, these are the typical EFs of gas and electric water heaters:

  • Electric water heaters: 0.75 to 0.95
  • Gas water heaters: 0.5 to 0.7

Let's say you have a gas water heater with an energy factor rating of 0.5; that means it's 50% efficient. using 50% of the gas to heat the water, while 50% goes up the flue pipe in the combustion process.

Does that mean if an electric water heater with a higher energy factor will save you more money?

Surprisingly, no.

You also need to look at the water heaters:

  • Fuel source cost
  • Ability to heat the water per billable unit

Compare fuel source cost + ability to heat water per billable unit

In Oklahoma, the electricity costs 3 times as much as gas, according to Centerpoint Energy. So while an electric water heater wastes less of its fuel source, the fuel itself costs more.

Also, electricity has less heating energy per billable unit. So electric water heaters use more electricity to heat the same amount of water as a gas water heater does with gas.
As a result of this, a gas water heater can heat water faster and use less energy than an electric water heater, saving you money.

Your big takeaway: Don't focus on water heater energy factor unless you're comparing 2 water heaters of the same fuel type.

If you want to see how much you'll really save from a new water heater, you should....

Find the Energyguide label to see possible savings

Look at the yellow Energyguide label on the water heater to see how much you'll spend annually. You should see it on your current water heater, allowing you to compare possible annual costs with a new water heater.

We say "possible" savings because how much you save depends on your hot water use. Many homeowners often use more hot water when their water heater is more efficient, ironically costing them more money.

Need help finding the right water heater for your Oklahoma family?

Ask our plumbing experts for help. They can help you find the water heater that's perfect for your family.

Pippin Brothers is the Lawton-area's most trusted heating, air conditioning and plumbing company. We've been serving Oklahoma since 1978. Contact us for more information.