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Here is the short answer: most household appliances use far less power than people assume, but a handful of them, mostly anything with a compressor or a heating element, use far more. A refrigerator runs on 100 to 250 watts most of the time, yet it can demand 700 to 1,200 watts for a second or two when the compressor kicks on. A phone charger sips 5 to 20 watts. An electric water heater can swallow 4,500 watts all by itself. If you are sizing a generator or a power station, the numbers below will get you 90 percent of the way there, and the last section shows you how to measure your exact appliances for a few dollars.
Running Watts vs. Surge Watts: The Distinction That Sizes Your Generator
Every appliance has two numbers that matter. Running watts (also called rated or continuous watts) is the power the appliance draws while operating normally. Surge watts (also called starting or peak watts) is the brief spike it needs to start up, and it only applies to appliances with electric motors or compressors.
Refrigerators, freezers, air conditioners, well pumps, and sump pumps all have compressors or motors, so their surge draw can be 3 to 7 times their running draw. Resistive loads like light bulbs, toasters, coffee makers, and space heaters have no surge at all. What you see is what you get.
This is why generator manufacturers advertise two numbers, like “4,500 starting watts, 3,600 running watts.” Your total running load must stay under the running rating, and your largest single surge, added on top of everything already running, must stay under the starting rating.
The Big Wattage Table: Common Appliances
These are realistic ranges based on typical modern appliances in American homes. Older units usually sit at the high end of each range, and newer Energy Star models at the low end.
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Refrigerator (standard 18-22 cu ft) | 100-250 | 700-1,200 |
| Chest freezer | 80-200 | 500-1,000 |
| Microwave (countertop) | 600-1,200 | None |
| Coffee maker (drip) | 550-1,200 | None |
| Toaster / toaster oven | 800-1,500 | None |
| Electric range (one burner) | 1,000-2,500 | None |
| Dishwasher | 1,200-1,800 | 1,500-2,200 |
| Window AC (5,000-8,000 BTU) | 450-900 | 1,200-2,200 |
| Central AC (3 ton) | 3,000-4,000 | 7,000-9,000 |
| Space heater | 750-1,500 | None |
| Electric water heater | 4,000-4,500 | None |
| Furnace blower fan (gas furnace) | 300-800 | 1,000-2,300 |
| Sump pump (1/3 to 1/2 HP) | 800-1,050 | 1,300-2,150 |
| Well pump (1/2 to 1 HP) | 1,000-2,000 | 2,100-4,000 |
| Washing machine | 400-1,000 | 1,200-2,250 |
| Electric clothes dryer | 3,000-5,400 | None significant |
| Television (LED, 50-65 inch) | 60-150 | None |
| Desktop computer with monitor | 150-400 | None |
| Laptop | 30-100 | None |
| Wi-Fi router and modem | 10-30 | None |
| Phone charger | 5-20 | None |
| LED light bulb | 7-15 | None |
| Ceiling fan | 50-100 | 100-200 |
| CPAP machine (no heated humidifier) | 30-60 | None |
| Garage door opener (1/2 HP) | 500-725 | 1,400-2,300 |
Two things jump out from this table. First, electronics are cheap to run. A TV, router, laptop, and a handful of LED lights together draw less than a single coffee maker. Second, anything that makes heat or moves water is expensive. A space heater at full blast uses as much power as ten refrigerators running at once.
Three Worked Examples: Adding It Up Correctly
Example 1: Basic outage kit
Say you want to keep a refrigerator (200W running, 1,000W surge), a Wi-Fi setup (25W), a TV (100W), and six LED bulbs (60W total) alive during an outage. Your running total is 200 + 25 + 100 + 60 = 385 watts. Your worst moment is when the fridge compressor starts while everything else is on: 25 + 100 + 60 + 1,000 = 1,185 watts. A small 1,800/2,200-watt inverter generator handles this with room to spare.
Example 2: Adding comfort loads
Take the same kit and add a microwave (1,000W) and a window AC (700W running, 1,800W surge). Running total: 385 + 1,000 + 700 = 2,085 watts. Worst-case surge scenario: everything running while the AC compressor restarts, roughly 385 + 1,000 + 1,800 = 3,185 watts. Now you are shopping in the 3,500 to 4,500 starting watt class. Our guide to the best portable generators for home outages breaks down which models fit this exact scenario.
Example 3: Well pump changes everything
A rural home with a 1 HP well pump (2,000W running, 4,000W surge) plus the basic kit from Example 1 needs 2,385 running watts but must absorb a surge event around 385 + 4,000 = 4,385 watts. The pump alone pushes you into a 5,000+ starting watt generator, even though your average consumption is modest. Motors, not electronics, dictate generator size. For a full walkthrough of this math, see our guide on how to calculate the right generator size.
Why Nameplate Labels Mislead You
Every appliance has a label listing volts and amps. Multiply them and you get a wattage figure, but it is the maximum the appliance is designed to draw, not what it actually uses. A refrigerator nameplate might work out to 700 watts, yet the unit averages 150 watts over a day because the compressor cycles on and off and rarely runs at design maximum.
The gap matters in both directions. Sizing from nameplates makes you overbuy. Guessing low leaves your generator stalling when the sump pump and fridge start at the same moment. The fix is measuring.
Measure Your Actual Appliances for Under $30
A plug-in electricity usage monitor sits between the outlet and the appliance and shows real-time watts plus accumulated kilowatt-hours. Plug your refrigerator into one for 24 hours and you will see its true running draw, its surge behavior, and its total daily energy use. That last number is gold if you are sizing a battery power station, since a fridge that averages 150 watts uses about 3.6 kWh per day, not the 4.8 kWh a 200-watt guess would suggest.
Check the current price of the Kill A Watt electricity usage monitor on Amazon.
Measure your five biggest loads and you can size a generator with confidence instead of padding every estimate. It also settles household arguments about what that old garage freezer really costs to run.
Hardwired Loads You Cannot Measure With a Plug-In Meter
Central AC, electric water heaters, well pumps, and furnaces are wired directly into your panel, so a plug-in meter cannot read them. For these, use the ranges in the table above, check the unit’s data plate for rated amps, or have an electrician clamp an ammeter on the circuit. If your goal is backing up these large 240-volt loads, you are in whole-house territory, and our guide on what size whole-house generator you need covers that sizing process step by step.
Quick Rules of Thumb
- Essentials only (fridge, lights, phones, Wi-Fi): 1,800-2,200 starting watts
- Essentials plus microwave, window AC, or sump pump: 3,500-4,500 starting watts
- Most of a small home, including a well pump: 5,000-7,500 starting watts
- Whole house with central AC: 10,000+ watts, usually a standby unit
- Only count the surge of the single largest motor, since two compressors rarely start in the exact same instant
- Leave 10 to 20 percent headroom; generators run quieter, cooler, and longer at partial load
One more note for battery power station shoppers: for batteries, daily watt-hours matter more than peak watts. A power station that can easily surge past a fridge startup may still only store 1,000Wh, which that fridge will drain in six or seven hours. Measure kilowatt-hours per day with your usage monitor, multiply by the days of backup you want, and size the battery from that number, keeping in mind that inverter losses mean you only get about 85 percent of a battery’s rated capacity into your appliances.
FAQ
How many watts does a refrigerator really use per day?
A modern 18 to 22 cubic foot refrigerator averages 100 to 250 running watts and cycles roughly a third to half of each hour, which works out to about 1.5 to 3.5 kWh per day. Older units and frost-heavy freezers can double that.
Can I run a space heater on a small inverter generator?
A 1,500-watt space heater will max out most 2,000-watt class inverter generators by itself, leaving almost nothing for other loads. It works, but nothing else can run alongside it. On battery power stations, resistive heaters are usually a poor use of limited watt-hours.
Why does my generator stall when the fridge and sump pump start together?
Their combined surge, often 2,300 to 3,300 watts, exceeded the generator’s starting capacity. Stagger the loads by plugging one in a few minutes after the other, or size up so the largest combined surge fits under the starting watt rating.
Do LED TVs and computers need surge capacity too?
No. Electronics draw slightly more for a fraction of a second at power-on, but it is negligible compared with motor surges. Only count meaningful surge for compressors, pumps, and motor-driven tools.