Cost of tumble drying vs outdoor line drying in the UK?
A family running five loads a week through a standard vented tumble dryer spends around £289 a year on drying alone at the April 2026 Ofgem price cap of 24.67 pence per kWh1.
Line drying costs nothing.
At DryTime we're outdoor line fanatics, but we'll try to be objective, ok?
Energy costs
| Method | Energy per load | Cost per load | Annual cost (5 loads/week) |
|---|---|---|---|
| Outdoor line drying | 0 kWh | £0.00 | £0 |
| Heat pump dryer (A+++) | ~0.9 kWh | ~£0.22 | ~£57 |
| Heated airer and dehumidifier | ~2.2 kWh | ~£0.54 | ~£141 |
| Condenser dryer | ~4.0 kWh | ~£0.99 | ~£257 |
| Vented dryer | ~4.5 kWh | ~£1.11 | ~£289 |
All energy costs calculated at the Ofgem April–June 2026 price cap unit rate of 24.67p/kWh. Annual figures based on five loads per week, 52 weeks. Appliance energy consumption figures from the Energy Saving Trust2.
Switching from a vented dryer to line drying saves around £289 a year. Switching to a heat pump dryer saves around £231 a year. The heat pump dryer costs more to buy (typically £400-£900), but at five loads a week it pays back that premium within two to four years.
The case of the disappearing clothes
The fluff in a dryer's lint filter is not household dust. It is fabric. Every cycle, garments shed a portion of themselves.
A 2022 study published in PLOS ONE found that a single vented tumble dryer load can release over 500,000 fibres into the air in 15 minutes. Cotton dominates: 93-99% of those airborne fibres are cotton. The volume is comparable to the microfibres washing machines release into wastewater.3
Condenser dryers collect moisture in a container rather than venting it outside. The microfibres come with it. A 2023 Northumbria University study estimated that over 600 tonnes of microfibres are collected in condensers and poured down drains across the UK and Europe every year. Many manufacturers advise rinsing the lint filter under the tap. That can increase waterborne pollution tenfold.4
Line drying is gentler on clothes. A 2023 study in the Journal of the Textile Institute found that the mechanical and thermal stress of machine drying reduces cotton's tensile strength by around 25% after just 20 cycles. The clothesline has no moving parts (apart from maybe a bit of whirligig) and produces no heat. Fabrics last longer for it.5
The carbon comparison
One tumble dryer cycle produces approximately 1.8 kg of CO27. At a typical UK average of around 240 g CO2 per mile for a petrol vehicle, that is the equivalent of driving roughly seven miles (11 km).
Line drying produces none.
Sunlight does disinfect. Sort of.
Sunlight has well-documented antibacterial properties. UV radiation damages bacterial DNA, and line-dried clothes do benefit from this. Some studies cite kill rates of 99.9 percent for pathogens including Staphylococcus aureus8.
Those figures come from laboratory conditions using UV-C radiation, however. UV-C is largely absorbed by the Earth's ozone layer and does not reach the UK in meaningful amounts. Natural sunlight delivers UV-A and UV-B, which are genuinely antibacterial, but at lower efficacy than the headline numbers suggest.
We can still chalk up some disinfection benefits to outdoor drying.
The pollen paradox
Here is the case for the tumble dryer that line-drying advocates rarely make (we did say we'd try).
Around 20 percent of UK adults have hay fever9. The NHS, the Met Office10, and Allergy UK all advise people with hay fever to avoid drying clothes outside when pollen counts are high. Wet fabric traps pollen. A peer-reviewed study by Choi et al. found that a tumble dryer removes over 99 percent of pollen from fabric11.
For one in five people in the UK, during spring and summer, the tumble dryer may be the sensible choice.
Wind beats sun
For outdoor drying, wind matters more than sunshine. Convective drying, the evaporation driven by airflow, moves moisture away from fabric faster than solar heat alone. A breezy, overcast day at 10°C can dry a full load more quickly than a still, sunny day at 20°C12.
The UK's Atlantic wind patterns make line drying more viable than the climate's grey reputation suggests, particularly in exposed northern and western areas. Checking wind speed and humidity before hanging out a wash matters more than simply checking whether it looks sunny. Humidity above around 80 percent stalls drying even in a stiff breeze.
A pressing concern
Line drying is not quite free if you iron more because of it.
A standard iron draws 2.0 to 2.5 kWh. Fifteen minutes of ironing costs around 12 to 16 pence at the current Ofgem rate. If line-dried clothes require 20 minutes more ironing per load than tumble-dried clothes, that adds roughly 16 to 21 pence per load, between £41 and £55 a year at five loads a week.
Line drying is still considerably cheaper than a vented dryer, even accounting for this. Shaking clothes before hanging, avoiding overloading the line, and maximising airflow reduces stiffness and narrows the ironing gap further.
The indoor swimming pool
Drying clothes inside without good ventilation moves all of that moisture into the air. A standard load of wet washing contains approximately two litres of water. Dried indoors on a radiator or airer, that becomes two litres of water vapour released into your home. For a family doing eight loads a week, that is around 16 litres of moisture per week added to indoor air.
Research from the Mackintosh Environmental Architecture Research Unit at Glasgow School of Art found that indoor drying can account for up to one third of total indoor moisture load, regularly exceeding safe humidity thresholds and increasing the risk of mould, asthma, and hay fever6.
If the heating is on, radiator drying is free. It is also not harmless.
The right choice?
There is no single answer. Season, housing type, and health all matter.
A family with hay fever sufferers may need a dryer from April through July. A household with outdoor space can line dry all year round, weather permitting. Someone in a flat with no outdoor space and poor ventilation faces a different calculation.
Knowing when outdoor conditions are genuinely good means the dryer stays off more often or moisture stays out of the home. DryTime takes temperature, windspeed, humidity, precipitation, solar radiation, and air pressure for your neighbourhood and returns a simple forecast for the next 48 hours, updated hourly. It is free, requires no install, and produces 0.03 g of CO2 per use, compared to the 1.8 kg of a single dryer cycle.
Last updated: April 2026 by the DryTime family in Somerset, UK.