How to Estimate Appliance Energy Cost
You do not need a whole-home audit to sanity-check one device. Watts, hours, and a rate produce a transparent estimate you can compare with a kill-a-watt meter or the Energy Guide label.
Start with running watts
Prefer continuous or average running watts over locked-rotor surge. For cycling loads like refrigerators, annual kWh on the Energy Guide divided by 365 is often better than a peak compressor rating.
Common estimate pitfalls
| Pitfall | Better approach |
|---|---|
| Using BTU/h as watts | Convert or measure electrical draw |
| Counting only one heavy day | Average across a typical week |
| Ignoring water-heating energy for laundry | Separate washer vs water heater |
| Blended bill rate with taxes | Use the volumetric energy rate line |
Worksheet sequence
1
Record watts
Nameplate or measured average.
2
Record hours/day
Include standby only if you model it explicitly.
3
Enter your $/kWh
From a recent bill energy charge.
4
Scale to month/year
Daily × days/month or × 365 for a first pass.
Specialized pages share one engine
AC, heaters, fridge, washer, and dryer pages use the same watts × hours × rate math with different defaults and FAQs.