Appliance running costs
What uses the most electricity in a home?
Which appliance uses the most electricity?
It depends entirely on hours and duty cycle, which is why a fixed top-ten list is misleading. Scored at the catalogue's typical usage and 0.18 USD/kWh, the hot tub leads at 591.7 kWh per average month ($106.50), ahead of the space heater at 365.7 kWh and the pool pump at 267.8 kWh. The hot tub alone is 33% of the 1,816 kWh these ten appliances add up to. Give the air conditioner a heatwave, or switch the space heater off for the summer, and the leader changes — the ranking below re-sorts live when you do exactly that.
Hot tub
uses the most electricity in this scenario
591.7 kWh per average month, $106.50 at 0.18 USD/kWh — 33% of everything listed here.
- Listed appliances
- 10
- Total (these rows)
- 1,816 kWh
- Total cost / month
- $326.88
- Second place
- Space heater
Scenario
Every appliance at the typical hours and duty cycle held in the appliance dataset.
Rate scales cost, never the kWh ranking.
| # | Appliance | Watts | Hours/day on | Duty cycle | Standby | Avg power 24 h | kWh / month | Cost / month | Share | vs defaults |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Hot tub | — | 810 W | 591.7 kWh | $106.50 | 33% | 1 | |||
| 2 | Space heater | 1 W | 501 W | 365.7 kWh | $65.83 | 20% | 2 | |||
| 3 | Pool pump | — | 367 W | 267.8 kWh | $48.21 | 15% | 3 | |||
| 4 | Dehumidifier | — | 250 W | 182.6 kWh | $32.87 | 10% | 4 | |||
| 5 | Air conditioner | 2 W | 241 W | 176.3 kWh | $31.73 | 10% | 5 | |||
| 6 | Clothes dryer | 2 W | 108 W | 79.0 kWh | $14.22 | 4% | 6 | |||
| 7 | Gaming PC | 5 W | 71 W | 51.7 kWh | $9.31 | 3% | 7 | |||
| 8 | Refrigerator | — | 52 W | 38.4 kWh | $6.90 | 2% | 8 | |||
| 9 | Freezer | — | 48 W | 35.1 kWh | $6.31 | 2% | 9 | |||
| 10 | Electric oven | 3 W | 38 W | 27.7 kWh | $4.98 | 2% | 10 |
What this ranking is, and is not
It ranks the appliances in the SnapEnergyLab catalogue against each other, under the inputs shown in the table. It is not a complete household total: whole-house heating, water heating, cooking, lighting, EV charging and everything not listed above are excluded, so the "share" column is a share of these rows only.
Method
- average power = (rated W × duty) over on-hours + standby W over off-hours
- kWh/day = average power ÷ 1000 × 24 h
- kWh/month = kWh/day × 30.44 days
- cost/month = kWh/month × rate
- rank = sort by kWh/month, descending
The "vs defaults" column compares the current position with the ranking produced by the unedited catalogue at the default rate of 0.18 USD/kWh.
Assumptions
- Starting watts, hours, duty cycles and standby draw come from appliances-1.0.0 and are typical examples, not measurements of your appliance.
- Every row is scored by energyEngine-1.2.0 — the same function behind each individual appliance-cost page, so a row here and its own page cannot disagree.
- An average month is 365.24 ÷ 12 = 30.44 days.
- Standby applies only during hours the appliance is switched off. Appliances that are powered 24 h/day therefore show no standby contribution.
- The rate changes cost but never the kWh order, because every row is scored at the same rate.
What can change the result?
- Hours per day — the single input that moves the ranking most.
- Duty cycle for anything thermostatic: fridges, freezers, heaters, air conditioners and hot tubs.
- Whether you own the appliance at all. A pool pump ranks near the top for the homes that have one and is absent everywhere else.
- Climate and season, which drive both hours and duty cycle for heating and cooling.
- Appliance age, size and efficiency class, which move rated watts inside the catalogue's stated range.
Why a fixed "top 10 appliances" list is wrong
Almost every page answering this question publishes a static ordering. That ordering is a hidden scenario: it assumes a particular climate, a particular set of owned appliances and a particular number of running hours, none of which are shown. Two households with the identical appliance set can produce completely different rankings, because the ranking is not a property of appliances — it is a property of how long each one runs at what power.
Three things decide position. Rated power sets the ceiling. The duty cycle decides how much of that power is actually drawn while the appliance is switched on — thermostatic loads like fridges, heaters and hot tubs spend much of their "on" time not drawing anything. Hours per day then converts power into energy. A 1,500 W heater used two hours a day loses to a 150 W refrigerator that never switches off.
That is why the table above lets you edit every one of those inputs, and why it shows how far each row moved from the catalogue defaults. A ranking that cannot move is a ranking that was never calculated.
National end-use shares are a different question
The table above is a SnapEnergyLab model of individual appliances against each other. The table below is not our model at all: it is a published survey statistic about the whole United States housing stock, averaged across homes that do and do not own each end use. The two answer different questions and must not be mixed. A national share cannot tell you what dominates your bill, and our appliance ranking cannot tell you what dominates a country.
| End use (US national) | Share of residential site electricity |
|---|---|
| Air conditioning | 19% |
| Space heating | 12% |
| Water heating | 12% |
The three largest categories and their shares of residential site electricity consumption in 2020. EIA notes that lighting and refrigerators are the next two largest end uses, and that shares move from year to year with the weather. U.S. Energy Information Administration, Residential Energy Consumption Survey (RECS) 2020. These categories are end uses, not appliances: "space heating" covers whole-house systems, and no equivalent whole-house heating or hot-water load appears in our appliance ranking above.
What normally sits above every appliance on this list
If your home heats space, heats water or charges a car with electricity, those loads usually beat everything in the table above, and the national shares say the same thing. They are not in the appliance ranking because they are not plug-in appliances with a single rated wattage — they depend on climate, building fabric and mileage. Use the dedicated tools for those, then compare the answers with the leaders here.
Your next decision
- Put a whole-house number around this rankingCompares a published benchmark, your bill converted to kWh, and a bottom-up load reconstruction.
- Cost out one appliance properlySame engine, one load at a time, with the full formula and a bill-to-kWh mode.
- Price the heating load that outranks all of theseDelivered heat compared across a heat pump and resistance heating at your own rate.
- Add these appliances up as one listRunning watts, average watts after duty cycle, kWh and monthly cost for a chosen combination.
- Turn an air conditioner's Btu/h rating into watts drawnCooling capacity is not electrical power — the EER decides what the ranking above should use.
- Why nameplate watts overstate consumptionThe duty-cycle problem that decides most of the ordering above.
Cost to run each appliance in this ranking
- Space heaterWhat a space heater costs to run, using realistic behaviour rather than nameplate watts.
- Air conditionerWhat an air conditioner costs to run, using realistic behaviour rather than nameplate watts.
- RefrigeratorWhat a refrigerator costs to run, using realistic behaviour rather than nameplate watts.
- FreezerWhat a freezer costs to run, using realistic behaviour rather than nameplate watts.
- Hot tubWhat a hot tub costs to run, using realistic behaviour rather than nameplate watts.
- Pool pumpWhat a pool pump costs to run, using realistic behaviour rather than nameplate watts.
- DehumidifierWhat a dehumidifier costs to run, using realistic behaviour rather than nameplate watts.
- Gaming PCWhat a gaming pc costs to run, using realistic behaviour rather than nameplate watts.
- Electric ovenWhat an electric oven costs to run, using realistic behaviour rather than nameplate watts.
- Clothes dryerWhat a clothes dryer costs to run, using realistic behaviour rather than nameplate watts.
Electricity cost tools
- Electricity cost calculatorWatts and hours in, cost per day, month and year out.
- Cost per kWh explainedThree different costs per kWh on one bill, and which one belongs in a calculator.
- Appliance wattage calculatorA configurable appliance list: what this combination draws, and what it costs.
- Watts to run a houseRunning, average and startup watts — separated, not averaged into one range.
Electrical units and conversion
- Watts to amps calculatorWatts ÷ (volts × power factor), and why a motor breaks the simple version.
- Refrigerator ampsThree correct answers — running, surge and average — and when each one applies.
- BTU to wattsBtu/h is cooling capacity; watts drawn depend on efficiency, not on 3.412.
- Ah → kWhAmp-hours and voltage to stored energy — exact conversion.