Hong Life CalculatorsUnderstanding the tumble dryer running cost calculator — concept and principle
A tumble dryer heats air and pushes it through wet laundry, which makes it one of the hungriest appliances in a home. This calculator estimates how much electricity your dryer uses and what it costs per month and per year, based on its power rating, hours per load, loads per month and your electricity price, and also shows the cost and energy of a single load. It helps when you compare vented and heat-pump models or decide whether to line-dry more often.
How it is calculated
Energy is power multiplied by time. Because electricity is billed in kilowatt-hours (kWh), the power in watts is first divided by 1,000.
- kWh per load = W ÷ 1000 × hours per load; cost per load = kWh per load × price
- kWh per month = kWh per load × loads per month
- Monthly cost = kWh per month × price per kWh; yearly cost = monthly cost × 12
Power (W) is the dryer's rated input power from the nameplate or manual. Four loads a week is about 17 loads a month. Use the all-in price per kWh, including taxes.
The principle
One watt is one joule per second, so a 2,500 W dryer running for one hour uses 2,500 watt-hours, or 2.5 kWh. Your meter counts exactly this quantity, so multiplying kWh by the tariff gives the cost. The formula assumes the dryer draws its full rated power the whole time. In reality the element cycles on and off and sensor drying ends early, so average power is often lower. Heat-pump dryers recycle heat instead of venting it outdoors and typically use roughly half the energy of a vented dryer for the same load.
Worked example
- Inputs: 2,500 W, 1 hour per load, 30 loads per month, $0.25 per kWh.
- One load: 2,500 ÷ 1,000 × 1 h = 2.5 kWh, costing 2.5 × $0.25 = $0.63.
- Monthly energy: 2.5 kWh × 30 loads = 75 kWh.
- Monthly cost: 75 kWh × $0.25 = $18.75.
- Yearly cost: $18.75 × 12 = $225.00.
| Power (W) | Monthly cost |
|---|---|
| 625 | $4.69 |
| 1,250 | $9.38 |
| 1,875 | $14.06 |
| 2,500 | $18.75 |
| 3,125 | $23.44 |
| 3,750 | $28.13 |
| 5,000 | $37.50 |
How to read the result
The result is an upper estimate for a dryer that runs at full power. If your monthly figure is a large share of your bill, drying is a good place to save. Two levers matter most: running time and heat source. A faster washer spin and a clean lint filter both shorten drying time. A heat-pump dryer with the same running time would land at roughly half of the figure shown, which you can compare against its higher purchase price.
Common mistakes
- Entering 30 loads a month when you only dry a few times a week.
- Forgetting that a gas dryer uses gas for heat; only the motor and controls run on electricity.
- Confusing watts (power) with kWh (energy).
Frequently asked questions
Is a heat-pump dryer worth it?
It usually halves energy use, so the yearly saving is roughly half of the yearly cost shown here. Divide the extra purchase price by that saving to get a simple payback period.
How can I find my dryer's real consumption?
Read your electricity meter before and after a cycle with other large appliances off.
Sources: International System of Units (SI), BIPM — definitions of the watt and joule · U.S. Department of Energy, Energy Saver — clothes dryers