Energy Star Appliance Savings Calculator

Read the estimated yearly electricity use, in kWh, from the EnergyGuide label on each model, or from the manufacturer's spec sheet. Enter your electricity rate from a recent bill, the price difference between the two models, and how many years you expect to keep the appliance.

Worked example: 700 kWh for the standard model and 600 kWh for the ENERGY STAR model, $0.1883/kWh, a $150 premium, and a 12-year life.

The certified model uses 100 kWh less a year, worth 100 × $0.1883 = $18.83. Over 12 years that adds up to $225.96. Take away the $150 premium and you are $75.96 ahead.

Payback is $150 ÷ $18.83 = 8.0 years. The better model does not move into profit until the end of its eighth year, so it is a modest win that depends on the fridge lasting.

Annual kWh saved = Standard model kWh − ENERGY STAR model kWh. If the certified model uses more, the result is set to zero.

Annual savings = Annual kWh saved × Electricity rate.

Lifetime net savings = Annual savings × Lifespan in years − Price premium. A negative result means the premium does not pay back within the life you entered.

Payback (years) = Price premium ÷ Annual savings. A $0 premium shows as immediate payback.

The calculator treats a lifespan below one year as one year, and does not discount future savings. A dollar saved in year ten counts the same as a dollar today.

Take a washer rated 400 kWh a year against an ENERGY STAR model rated 320 kWh, at the same $0.1883/kWh, with a $100 premium and an assumed 14-year life.

It saves 80 kWh, worth $15.06 a year. Payback comes in 6.6 years, and lifetime net savings are $110.90.

This washer saves less each year than the refrigerator, yet comes out further ahead. The premium is smaller compared with the annual savings, and the washer is assumed to last longer. Payback depends as much on the price gap as on the kWh gap.

The washer figure also leaves out water. ENERGY STAR says certified washers use about 30% less water, and the calculator does not count it, so homes on a water meter save more than it shows.

The yellow EnergyGuide label, required by the FTC on refrigerators, dishwashers, clothes washers, water heaters, air conditioners, televisions and other appliances, shows three numbers you can use:

• Estimated yearly energy cost: based on typical use and a national average energy price.
• A cost range bar: where this model sits among similar models.
• Estimated yearly electricity use in kWh.

Enter the kWh figure, not the dollar figure. The FTC notes that the cost is only an estimate based on the national average price, while your own cost depends on your rate. Multiplying the kWh by your own tariff, as this calculator does, corrects for that. At $0.30/kWh, the same refrigerator pair saves $30 a year and pays back in 5.0 years, with $210 of lifetime savings.

Compare like with like. Labels are only comparable within the same category and a similar size and configuration. A smaller fridge will show fewer kWh without being more efficient.

The comparison above assumes you are buying anyway, so the premium is the only extra cost. If you are replacing a working appliance early, the extra cost is the full price of the new one.

Say an old refrigerator that still works is rated 650 kWh, and a new ENERGY STAR model is rated 450 kWh and costs $900. Enter $900 as the premium with a 12-year life. It saves 200 kWh, or $37.66 a year, but payback takes 23.9 years. Over 12 years you end up $448.08 behind.

Payback can also fail when the appliance leaves your hands early. Keep the refrigerator pair from the first example for 7 years instead of 12, perhaps because you are moving, and the net result is −$18.19.

In general, early replacement makes sense when the old unit uses far more energy than its label suggests, when electricity is expensive, or when it is close to failing anyway. For a working appliance of average efficiency, it is usually better to wait until it fails and then buy the efficient model.

EnergyGuide kWh figures come from standardized tests with assumed usage. A large family running more laundry loads, or a fridge in a hot garage, will use more than the label says, and a light user less.

Only electricity is counted. Water savings and gas used to heat water in the washer or dishwasher are not included, and neither are installation, haul-away fees, rebates or financing. The calculator uses one flat rate and does not discount savings.

The lifespan is your estimate. If the appliance fails early, the lifetime savings shown will not materialise.

To find out what an appliance you already own costs to run, the appliance energy calculator works from its wattage and hours of use. The home energy audit calculator shows how appliances compare with heating and cooling on the whole bill. Before you pay a washer premium, the cold wash laundry savings calculator shows what washing at a lower temperature saves for free.

Longer paybacks look different once future savings are discounted, which the Simple vs Discounted Payback on Energy Upgrades guide explains. The Appliance Energy Cost Guide covers typical appliance watts and kWh.