The true cost of each option

The surface comparison is simple: airer costs £0 to run, dryer costs money. But the full picture is more nuanced.

Airer costs:

Tumble dryer costs:

On pure electricity cost, the airer wins, but by 10p per load overnight on Agile. Over a year of 4 loads per week, that is £20. The monetary difference between airer and overnight-timed dryer is smaller than most people expect.

Clothes airer: the hidden costs (time, space, damp risk)

The airer has real advantages. It is free to run, gentle on clothes, and requires no machine to maintain. But three hidden costs often go uncounted.

Time cost. Hanging a full laundry load on an airer takes 20-40 minutes. Loading a tumble dryer takes under 5 minutes. For a household doing 4 loads per week, the airer requires an extra 60-140 minutes of active time weekly. Over a year, that is 52-122 hours. That time has value, even if it is not financial.

Space cost. A full-size folding airer occupies roughly 1.5 square metres of floor space and must stay there for hours. In a small flat or house with limited living space, this is not trivial. The tumble dryer's footprint is fixed and enclosed. It does not colonise the living room.

Damp and mould risk. Drying clothes indoors releases significant moisture into the air. A typical laundry load contains 2-4 litres of water. In poorly ventilated UK homes, that moisture raises indoor humidity, promotes mould growth, and can aggravate respiratory conditions. The NHS and UK housing charities both highlight indoor drying as a contributing factor to damp problems in UK homes. If your property already has damp issues, the airer may not be the low-cost option it appears, once you factor in the long-term cost of mould treatment or health impacts.

Tumble dryer overnight on Agile: the real cost vs convenience value

On Octopus Agile with overnight timing, a condenser dryer cycle costs 10p. A heat pump dryer cycle costs 4p. At 4 loads per week, the annual cost is £20 for a condenser and £8 for a heat pump.

Against that cost, consider the convenience value:

If you check AgileAlert each evening and set the delay start, the marginal cost of using the dryer instead of the airer is around 10p per load. For most households, the convenience value of a dry, soft load ready by morning exceeds 10p.

The relevant comparison is not "free airer vs expensive dryer." It is "free airer vs 10p overnight dryer." Framed correctly, the decision is much closer to neutral on cost and clearly in favour of the dryer on convenience.

The hybrid approach: airer for most, dryer for urgent needs

The financially optimal approach for most households is hybrid use:

Use the airer for: lightweight summer clothing, towels when there is time, clothes that do not need to be ready urgently, items that need flat drying rather than tumbling.

Use the tumble dryer overnight on Agile for: school uniforms and work clothes needed the next morning, towels and bedding when the airer is already full, heavy cotton that would take 24+ hours on an airer in autumn or winter, anything where the damp from indoor airing would be a problem.

This hybrid approach captures the zero cost of the airer for appropriate loads while using the dryer's speed and convenience for time-sensitive ones, and always at the overnight rate by setting a delay start.

The full guide to setting delay start on your specific dryer brand is at How to Use Delay Start on Your Tumble Dryer: All Brands Guide.

Dehumidifier plus airer: the middle option

Some households use a dehumidifier alongside an indoor airer. The dehumidifier pulls the released moisture from the air, preventing damp problems while the airer handles the actual evaporation.

The running cost: a typical 12-litre dehumidifier uses 200-300W, costing 8-12p per hour on a standard tariff, or around 1p per hour on overnight Agile. Running it for 8 hours overnight alongside drying clothes costs approximately 8-10p, comparable to running the tumble dryer itself overnight.

The dehumidifier-plus-airer approach has merit in homes with damp or mould problems where the airer alone would worsen conditions. It does not save money over the overnight-timed dryer at Agile rates. The main benefit is the option to use it in homes where a tumble dryer is not practical (rented flats, very small spaces).

If you have both options available, the tumble dryer at overnight Agile rates remains the most time-efficient and comparably priced solution. Use AgileAlert to find tonight's rate and the 10p per cycle becomes routine, not a decision.

Frequently asked questions

Is using an airer always cheaper?
On electricity cost alone, yes. An unheated airer uses no electricity. But when you factor in the value of time saved, the space the airer occupies, and the damp it introduces indoors, the comparison narrows considerably. On Octopus Agile overnight rates, the tumble dryer costs 10p per load at 4p/kWh. That gap in electricity cost is small enough that convenience often justifies the dryer, especially in winter when airer drying times stretch to 12-24 hours.
Does drying clothes inside cause damp problems?
Yes, it can. A full laundry load releases 2-4 litres of moisture into the air as it dries. In a well-ventilated property this disperses harmlessly. In poorly ventilated UK homes, especially flats and older houses, it raises indoor humidity significantly and can contribute to mould growth on walls and ceilings. If your property already has damp or mould, indoor airing without a simultaneous dehumidifier is likely making it worse. The tumble dryer or the dehumidifier-plus-airer combination removes this moisture problem entirely.
Can I use an airer in winter effectively?
Outdoors in winter: generally no. Cold, damp UK winter air does not evaporate moisture from fabric effectively. Indoors in a heated room: yes, but slowly. Heavy cotton items take 18-24 hours. Drying time on an indoor airer in winter is long enough that for most households, the tumble dryer becomes the practical choice for the majority of loads between October and March. The overnight Agile rate keeps the cost at 10p regardless of season.
What is the cheapest way to dry clothes in the UK?
Outdoor line drying in summer is free and fast. An indoor airer is free but slow and adds moisture. A tumble dryer costs 10p per load at overnight Agile rates. A heated airer costs 4-8p per hour (so 32-64p for an 8-hour overnight dry). The tumble dryer on overnight Agile is cheaper than a heated airer, faster than any airer option, and avoids the damp problem of indoor airing. For Agile customers, the overnight-timed tumble dryer is the best all-round choice for most of the year.