Clothes Line Vs Tumble Dryer Savings Calculator
Compare the cost, electricity use and carbon saving from drying laundry on a line instead of running a tumble dryer.
Laundry And Tariff Inputs
Annual Saving Result
Drying indoors can add moisture to a home. Ventilation and damp risk matter as well as electricity cost.
What The Saving Means
A tumble dryer uses electricity each time it dries a load. Line drying removes most or all of that electricity use, but the real saving depends on how many loads you move away from the dryer, the energy use of your appliance and your unit rate. Heat-pump dryers can use much less electricity per load than older vented or condenser models, so their saving from line drying is smaller for the same number of loads.
The estimate excludes standing charge because you normally pay that even if the dryer is switched off. It also excludes wear on clothing, ironing time, damp treatment, appliance purchase cost and the value of your time. Those can still matter. Use the one-off rack cost field if you are buying a drying rack or outdoor line and want a simple payback period.
Energy Formula
The calculation starts with weekly dryer loads and the number of weeks you plan to line dry. It multiplies those by the share of loads moved to line drying and the kWh per dryer load. Any indoor drying energy, such as a dehumidifier, is then subtracted. Cost saving is net kWh saved multiplied by your electricity unit rate.
| Formula line | How it is calculated | Why it matters |
|---|---|---|
| Moved loads | loads per week x weeks x line-drying percentage | Only the loads you actually move away from the dryer save energy. |
| Dryer kWh avoided | moved loads x tumble dryer kWh per load | This is the gross electricity avoided. |
| Indoor energy | moved loads x indoor kWh per load | Fans or dehumidifiers reduce the net saving. |
| Cost saving | net kWh saved x pence per kWh | Standing charge is not included. |
| Carbon saving | net kWh saved x carbon factor | Carbon factors are averages and change over time. |
Drying Scenarios
Outdoor summer line
Five loads a week for 30 weeks, at 2.2 kWh per load and 25p per kWh, saves about GBP 66 if 80% of those loads avoid the dryer.
Heat-pump dryer owner
If the dryer uses only 1 kWh per load, the cost saving is smaller. Line drying can still help with carbon and appliance wear, but payback on new equipment is slower.
Indoor drying with dehumidifier
If each indoor load uses 0.4 kWh through a dehumidifier, that energy should be deducted. It may still be cheaper than a dryer, but the gap narrows.
Typical Dryer Energy Checks
| Dryer type or check | Typical entry approach | Practical note |
|---|---|---|
| Heat-pump dryer | Often around 1 to 2 kWh per load | Check your appliance label or smart plug data. |
| Condenser dryer | Often higher than a heat-pump model | Large cotton loads can use much more than mixed synthetics. |
| Vented dryer | Often one of the higher-use types | Vent condition and load size affect running time. |
| Washer-dryer drying cycle | Use cycle kWh from manual or plug meter | Small drum drying can need more cycles for a full wash. |
| Smart plug measurement | Best household value | Run several normal loads and use the average kWh. |
Damp, Ventilation And Laundry Quality
Outdoor line drying has no household electricity use, but it depends on weather, space and time. Indoor airers can be useful in flats and winter, yet wet washing releases moisture into the room. If condensation, mould, asthma triggers or poor ventilation are a concern, cost saving is not the only issue. A dehumidifier can reduce damp risk, but it uses electricity and should be entered in the indoor energy field.
Clothing can also behave differently. Towels may dry softer in a tumble dryer, while shirts may need less ironing after careful line drying. Heavy bedding may dry slowly indoors. The best routine can be mixed: line dry most loads, use the dryer for towels during wet weeks, and keep a moisture-aware plan for winter.
FAQs
How much does line drying save?
It depends on loads, dryer kWh per load and unit rate. The default five loads per week for 30 weeks, with 80% moved to line drying, saves tens of pounds a year rather than hundreds for many households.
Should I include the electricity standing charge?
No. Standing charge is paid for having the supply available, not for each dryer load. Use your pence per kWh unit rate only.
What if I use a dehumidifier?
Enter the dehumidifier or fan energy per moved load. This reduces the net saving but may be sensible where damp risk is a concern.
Is a heat-pump dryer cheap enough to ignore?
Not always. It may be much cheaper than older dryers, but repeated loads still use electricity. Measure kWh per load if you want a close estimate.
Can line drying reduce carbon?
Yes, if it avoids net electricity use. The carbon estimate uses an editable average electricity factor, so change it if you have a newer official factor.
Does this compare clothes wear?
No. Some people value lower fabric wear from air drying, while others value dryer speed. The estimator focuses on energy, cost and carbon.
Sources
- Ofgem. (2026). Energy price cap by region and payment type. Ofgem. https://www.ofgem.gov.uk/energy-price-cap
- Energy Saving Trust. (2026). Home appliances. Energy Saving Trust. https://energysavingtrust.org.uk/advice/home-appliances/
- Department for Energy Security and Net Zero. (2025). Greenhouse gas reporting: conversion factors 2025. GOV.UK. https://www.gov.uk/government/collections/government-conversion-factors-for-company-reporting
- NHS. (2026). Damp and mould. NHS. https://www.nhs.uk/common-health-questions/lifestyle/can-damp-and-mould-affect-my-health/