Information current as of 09/05/2026.
Start by comparing 12 months of electric bills and monthly kilowatt-hours, separating electricity from gas or other fuels and noting seasonal changes. Then rank major loads such as heating and cooling, electric water heating, dryers, pool equipment, EV charging, refrigeration, and always-on electronics. Use EnergyGuide information, nameplate ratings, and a properly rated plug-in monitor for accessible devices; use a utility program or qualified professional for hardwired equipment.
1. Start with your electricity bills
Collect the last 12 months of electric bills or utility-portal data. Record monthly kilowatt-hours, cost, billing dates, and any available average daily use. Compare seasons and note changes in weather, occupancy, or equipment. Separate electricity from gas and other fuel bills so you are diagnosing electric use rather than total household energy use. Kilowatt-hours measure accumulated electricity use; watts and kilowatts describe the rate of use at a particular moment.
2. Use seasonal changes to narrow the search
A strong increase during hot or cold weather can point toward heating or cooling, while changes in hot-water demand can point toward electric water heating. Compare these patterns with the systems in your home before focusing on small electronics. A whole-home comparison should include heating and cooling as well as appliances, lighting, and hot water.
3. Rank likely high-use equipment
Check heating and cooling equipment, electric water heating, clothes dryers, pool or spa equipment, EV charging, refrigerators and freezers, electric ranges and ovens, dehumidifiers, space heaters, pumps, and other equipment that runs for long periods or uses substantial power. Include miscellaneous plug loads and electronics rather than looking only at visible appliances. A high wattage rating alone does not prove that a device is the largest energy user because operating time also matters.
4. Check labels and estimate energy use
Make an inventory of major appliances and record the yellow EnergyGuide estimate where available, along with nameplate watts or amps and approximate operating time. EnergyGuide annual electricity and cost figures are estimates, so actual use can differ. For an accessible device, estimate energy with: kilowatt-hours = watts × hours used ÷ 1,000. Compare the result with the electricity price shown on your bill, without treating the nameplate rating as average consumption.
5. Measure compatible plug-in devices safely
Use a properly rated plug-in electricity monitor only with compatible, accessible plug-in equipment. Measure cycling or variable-use devices over a period long enough to represent normal operation, then use the accumulated kilowatt-hours or average reading rather than relying on one instant. Follow the monitor and appliance instructions, and stop if a plug, outlet, cord, or appliance is damaged, wet, discolored, or unusually hot.
6. Handle hardwired loads and unexplained use professionally
Do not open an electrical panel, remove covers, probe outlets, or measure live wiring yourself. A normal plug-in monitor cannot diagnose many central HVAC systems, electric water heaters, baseboard heaters, pool pumps, or EV chargers. If appliance checks do not explain the bill, check whether your utility offers interval data, an energy report, a meter-lending program, or an audit referral, or hire a qualified electrician or professional energy auditor.
7. Check standby power after larger loads
Some equipment uses electricity while it appears to be turned off or is in a low-power mode. After checking major continuously operating loads, measure suitable electronics over time rather than judging standby use from a brief reading. Do not rely on unverified plug-in products marketed as energy-saving devices.
Sources
- Measuring Standby Power
- Building Electric Appliances, Devices, and Systems
- Home Energy Yardstick
- Energy Efficiency in the Home
- Switched On 28
- Home Energy Checklist
- Understanding Your Utility Bill
- Energy Saver: Tips on Saving Money and Energy in Your Home
- How Does the Yardstick Work?
Frequently asked questions
How can I tell what is using the most electricity in my house?
Compare 12 months of electric bills first, then use seasonal patterns to identify likely heating, cooling, or water-heating loads. Check EnergyGuide information and nameplates, estimate use from watts and operating time, and use a properly rated plug-in monitor for compatible devices. For hardwired equipment or unexplained whole-home use, contact your utility or a qualified professional.