In short
- According to Argentina’s official table (ENRE), a 5 kg automatic washer is rated at 500 W, but on average uses 175 Wh per hour of washing: the motor isn’t at full power the whole time.
- If the same washer heats its own water, it goes up to 2,500 W and 875 Wh per hour: 5 times more.
- According to ENERGY STAR, heating water is about 90% of the energy a washer uses. Switching from hot to warm cuts it in half; cold cuts it even more.
- One cold load a day is about 5.3 kWh a month; heating the water, about 26.3.
Words you’ll see
- Watt (W): power at any moment. Wh and kWh: energy over time (1 kWh = 1,000 Wh). More in watts, kWh, volts and amps.
- Automatic washer: one that fills, washes, rinses and spins on its own.
- Twin-tub: the older semi-automatic type where you move the clothes to the spin tub by hand.
- Heating element: the part that heats the water inside the washer; it’s what uses the most.
How many watts does a washing machine use?
| 5 kg washer | Power | Energy in one hour |
|---|---|---|
| Twin-tub | 200 W | 80 Wh |
| Automatic, cold water | 500 W | 175 Wh |
| Automatic, heats its own water | 2,500 W | 875 Wh |
These are the figures from Argentina’s electricity regulator (ENRE). The U.S. Department of Energy table reproduced by Virginia Tech gives 350 to 500 W for a clothes washer without water heating: they agree.
Why hot water changes everything
According to ENERGY STAR (the U.S. government’s efficiency program), heating water consumes about 90% of the energy a clothes washer uses. It adds:
- Switching from hot to warm can cut energy use in half; the cold cycle cuts it even more.
- Unless you’re dealing with oily stains, cold water will generally do a good job.
- The “sanitary” or extra-hot cycle increases energy use significantly: only use it when needed.
If your hot water comes from a water heater (electric, gas or solar), the washer doesn’t heat it, but you pay for that heat at the water heater. See how much an electric water heater uses.
Worked example: one load a day for a month
We count each load as one hour, like the electricity usage calculator (check your cycle’s length and change it there):
- Cold: 175 Wh × 30 loads = 5,250 Wh, about 5.3 kWh a month.
- Heating the water: 875 Wh × 30 = 26,250 Wh, about 26.3 kWh a month.
- Difference: about 21 kWh a month. At an example price of $0.15 per kWh (use the one on your bill), $3.15 a month; about $37.80 a year.
ENERGY STAR says the average American family washes about 300 loads a year, about 25 a month: at that pace the numbers come out a little lower.
The biggest laundry costs: heating and drying
In the same ENRE table, a heated tumble dryer uses 950 Wh in an hour: more than five cold washes. ENERGY STAR recommends air-drying when you can: it saves energy and your clothes last longer.
How to choose a washer that uses less
- ENERGY STAR certified washers use about 20% less energy and about 30% less water than regular ones.
- Front-load certified washers, according to ENERGY STAR, use about 50% less energy and water than a top-load agitator washer, and about 25% less than a top-load impeller washer.
- Check its energy label: it gives kWh per year for a set number of loads.
Common mistakes
- Running half loads. According to ENERGY STAR, a washer uses about the same energy whatever the load size: run full loads.
- Washing everything hot out of habit. It’s nearly all the energy, and cold water usually gets clothes clean.
- Looking only at the 500 W. That’s the motor; if the washer heats water, its element draws five times more.
When to call an electrician or a technician
A washer combines water and electricity: if it gives a tingle when touched, trips the GFCI/RCD or the plug gets hot, unplug it and call an electrician (see why a breaker trips). If it doesn’t heat, doesn’t spin or leaks, call an appliance technician.
Sources and references
- Ente Nacional Regulador del Gas y la Electricidad (Argentina). Consumo básico de electrodomésticos (5 kg automatic washer, 500 W and 175 Wh per hour; with water heating, 2,500 W and 875 Wh; twin-tub, 200 W and 80 Wh; heated dryer, 950 W).
- ENERGY STAR (EPA and U.S. Department of Energy). Clothes Washers (water heating about 90% of energy; hot to warm halves it; full loads; 20% less energy and 30% less water; front-load; about 300 loads a year per family; air-drying).
- Grisso, R., Walker, M. and Ignosh, J., Virginia Cooperative Extension (Virginia Tech), 2020. Estimating Appliance and Home Electronic Energy Use (Department of Energy table: clothes washer, 350–500 W).
Frequently asked questions
How many watts does a washing machine use?
A 5 kg automatic washer is rated at about 500 W and averages 175 Wh in an hour of cold washing, according to Argentina’s ENRE table. If it heats its own water, it goes up to 2,500 W and 875 Wh per hour.
How much electricity does a washing machine use per month?
One hour-long cold load a day is 175 × 30 = 5.25 kWh a month. Heating the water, 875 × 30 = 26.25 kWh: five times more.
Does washing in cold water save electricity?
Yes, a lot. According to ENERGY STAR, heating water is about 90% of the energy a washer uses, and switching from hot to warm already cuts it in half.
