Energy Costs · Calculator
Average Electricity Usage by Appliance: kWh Estimator and Usage Table
Appliance energy is watts × hours ÷ 1,000 = kWh, and kWh × your rate gives the cost. A typical US home uses somewhere around 850–900 kWh a month, but real homes range from under 500 to over 2,000 depending on climate, size and whether heating and hot water are electric. Heating, cooling and water heating are usually the biggest loads; small electronics add up mainly because they run all day.
Appliance electricity usage estimator
How to calculate an appliance's electricity use
Electricity is billed in kilowatt-hours. One kWh is 1,000 watts running for one hour, so any appliance's energy is just its power multiplied by time:
kWh per day = Watts × Hours per day ÷ 1,000
kWh per month = kWh per day × Days used
Cost = kWh × Rate ($/kWh)
Example with the calculator defaults: a 55-inch LED TV drawing 100 W for 5 hours a day uses 100 × 5 ÷ 1,000 = 0.5 kWh a day. Over 30 days that is 15 kWh, which costs about $2.55 a month or $31 a year at $0.17/kWh.
For appliances that cycle on and off, such as refrigerators, dehumidifiers and anything with a thermostat, use the average power over the period, or enter the full running wattage with only the hours the compressor or element actually runs. The calculator's refrigerator option already uses a 24-hour average.
Typical appliance usage table
Typical US figures for common household loads. Your appliances may differ by a factor of two in either direction, especially older ones.
| Appliance | Typical watts while running | Typical use | Typical kWh per month |
|---|---|---|---|
| Central AC, 3 ton (summer) | 2,500–3,500 | 8 h/day of compressor run | 600–840 |
| Heat pump heating, 3 ton (winter) | 2,500–4,000 | 8–12 h/day | 600–1,400 |
| Electric water heater, tank | 4,500 (element) | 2–3 h/day of element time | 270–405 |
| Window AC, 10,000 BTU/h | 800–1,000 | 8 h/day | 190–240 |
| Space heater | 1,500 | 6 h/day | 270 |
| Dehumidifier, 50-pint | 550–700 | 12 h/day | 200–250 |
| EV, Level 2 charging | 7,200 | about 1,000 miles/month | 250–350 |
| Pool pump, single-speed | 1,500–2,000 | 8 h/day | 360–480 |
| Refrigerator, modern | 50–70 average | 24 h/day | 35–50 |
| Electric clothes dryer | 2,000–5,000 | 12 loads/month | 30–60 |
| Dishwasher | 1,200–1,500 | 1 cycle/day | 30–45 |
| Electric oven | 2,000–3,000 | about 1 h/day | 30–60 |
| Desktop PC and monitor | 100–300 | 6 h/day | 18–54 |
| TV, 55-inch LED | 60–120 | 5 h/day | 9–18 |
| Microwave | 1,000–1,200 | 15 min/day | 8–9 |
| Wi-Fi router and modem | 10–20 | 24 h/day | 7–14 |
| Laptop | 30–60 | 6 h/day | 5–11 |
| LED bulb | 8–12 | 5 h/day | 1.2–1.8 each |
Worked example: a winter space heater
Select the 1,500 W space heater and set 6 hours a day for 30 days at $0.17/kWh. The calculator returns 1,500 × 6 ÷ 1,000 = 9 kWh a day, 270 kWh a month, about $45.90. That one heater would add roughly 30% to a typical home's monthly use. Compare the TV in the earlier example at 15 kWh: a resistive heating load can use close to twenty times as much as an electronics load.
The same reasoning explains why replacing a bulb with an LED saves a few dollars a year, while lowering heating or cooling use by a few degrees can save far more.
Where most household kWh go
In most climates, space conditioning dominates: air conditioning in the South, heating in homes with electric heat in the North. An electric tank water heater is often the next largest single load, followed by laundry drying, refrigeration and cooking. Plug-in electronics are small individually, but always-on devices add up because they run 720 hours a month. A cluster of standby loads totaling 30 W around the clock adds about 22 kWh a month.
For the big loads, use the dedicated calculators, which account for efficiency ratings and runtime: cost to run an air conditioner, heat pump running cost, cost to run an electric heater and dehumidifier running cost.
Finding an appliance's real wattage
- Plug-in watt meter: the most accurate option for anything with a standard plug. Leave it in place for a day or a week to capture cycling and standby use.
- EnergyGuide label: refrigerators, freezers, water heaters and some others list estimated annual kWh. Divide by 12 for a monthly figure.
- Nameplate: lists watts, or volts and amps. Volts × amps gives the maximum draw, not the average, so it overstates use for motors and compressors.
- Smart meter data: many utilities show hourly use online. Switch a large load on and off and watch the change.
Don't open panels or measure current inside hard-wired equipment such as water heaters, ranges or HVAC units unless you are qualified to work on live 240 V circuits. Use the label or a whole-home energy monitor installed by an electrician.
Understanding your electricity rate
The calculator uses a single rate per kWh. Real bills can be more complicated:
- All-in rate: divide your total bill by the kWh used. This captures delivery charges and taxes, and is the best single number for estimates.
- Tiered rates: the price rises after a monthly threshold, so the last kWh you add (for example, a new space heater) may cost more than your average.
- Time-of-use rates: afternoon and evening hours cost more. Shifting dishwashers, dryers and EV charging to off-peak hours saves money without saving energy.
- Fixed monthly charges don't change with usage, so leave them out when estimating the cost of a single appliance.
Sizing backup power from the same numbers
The watts in the table are running watts. Motors and compressors briefly draw two to three times more when starting, which matters if you are choosing a generator or battery system. Add up the running watts of everything you want to power at once, then allow for the largest starting surge; the generator sizing calculator does both steps.
Frequently asked questions
How many kWh does an average house use per month?
US homes average roughly 850–900 kWh a month, but the range is wide. Small apartments with gas heat may use 300–500 kWh; large all-electric homes in hot or cold climates can exceed 2,000 kWh in peak months.
How do I convert amps to kWh?
Multiply amps by volts to get watts (for example, 10 A × 120 V = 1,200 W), then multiply by hours and divide by 1,000. Nameplate amps are a maximum, so measured values give a better estimate.
Do appliances use power when switched off?
Many do. TVs, game consoles, chargers and anything with a clock or remote draw standby power, usually 0.5–5 W each. A smart power strip or unplugging rarely used items trims this load.
Which appliance uses the most electricity?
In most homes it is the heating or cooling system, followed by an electric water heater if you have one. Among plug-in appliances, space heaters, dehumidifiers and window ACs are the big users because they draw hundreds to over a thousand watts for many hours.
Last reviewed 2026-10-28