How a Dehumidifier Helps Laundry Dry
It removes water vapour from the air around drying clothes, helping the room deal with the moisture released by the laundry.
Wet laundry releases water into the surrounding air as it dries. Which? confirms that a dehumidifier can be used to help dry laundry indoors, while Energy Saving Trust recommends considering one for excessive moisture or to help with washing dried inside [S1][S2].
The useful distinction is that an airer provides the surface on which clothes dry, while the dehumidifier manages moisture in the room air. Its performance is therefore affected by both the appliance and the conditions around the laundry.
- Laundry releases moisture into the room air
- The dehumidifier removes some of that airborne moisture
- Air movement and garment spacing affect evaporation
- Room temperature and humidity affect appliance performance and drying
- The process is not governed by the dehumidifier's litres-per-day label alone
A Better Setup for Indoor Laundry
Use a suitable room, space garments for airflow, keep the unit unobstructed and contain or remove the moisture without blocking necessary ventilation.
There is no universal rule that every dehumidifier should sit one or two metres from an airer. Appliance designs differ, so follow the manufacturer's minimum clearances and placement instructions. Keep the air inlet and outlet clear and do not drape wet laundry over the appliance.
If you are using the dehumidifier to concentrate moisture removal around one drying load, keeping the laundry in a defined room can be useful. But a dehumidifier does not provide fresh air. Energy Saving Trust says ventilation is essential for reducing moisture, and current UK housing guidance also treats drying clothes as a moisture source that needs appropriate ventilation or moisture control [S2][S3].
- Use an airer and leave space between garments
- Follow the appliance manual for clearance from walls, furniture and laundry
- Keep inlet and outlet airflow unobstructed
- Use laundry mode if your model provides it, following its manual
- Do not block permanent vents or treat a dehumidifier as a replacement for ventilation
| Setup Question | What to Check |
|---|---|
| Where should the unit go? | Follow manufacturer clearance guidance and keep airflow paths clear |
| Should the room be contained? | Limit moisture spreading while maintaining required ventilation |
| How should clothes be hung? | Avoid overlapping garments and allow air to move around them |
| Which mode should I use? | Use the manufacturer's laundry mode if available; otherwise follow its normal humidity-control guidance |
| What if condensation still appears? | Treat it as evidence that the room is struggling with the moisture load and improve the moisture-control setup |
Why There Is No Universal Drying Time
The same dehumidifier can produce different drying times because the starting water content, fabrics and room conditions change from load to load.
Avoid treating a capacity label such as 12L, 16L or 20L per day as a promise that a washing load will dry in a particular number of hours. Extraction ratings are measured under specified test conditions and do not directly convert into laundry drying time.
A higher washing-machine spin can leave less water for the room to remove. Thick towels, tightly packed garments, a cold room or restricted airflow can all change the result. Which?'s indoor-drying testing also shows that the best drying method depends on factors including how much laundry you need to dry [S1][S4].
- Starting water left after the washing-machine spin
- Load size and garment thickness
- Spacing and airflow around the airer
- Room temperature and starting relative humidity
- Dehumidifier technology, settings and actual extraction under those conditions
Laundry Mode: What It Does and What It Does Not Prove
Laundry mode is an appliance-specific setting intended for drying laundry, but its exact fan, humidity and compressor behaviour depends on the model.
Do not assume every laundry mode means maximum fan speed, continuous compressor operation or the same target humidity. Those behaviours are product-specific. Use the instructions supplied with your dehumidifier.
Likewise, setting every dehumidifier to its lowest possible humidity target is not a universal substitute for laundry mode. The useful test is whether your chosen setting dries the load satisfactorily while controlling room moisture and using an acceptable amount of electricity.
- Check what laundry mode means on your specific model
- Do not assume a universal 30–35% target
- Do not assume the compressor runs continuously
- Compare completed-load results rather than mode names
- Return the appliance to your normal household humidity strategy after laundry drying
How to Calculate the Real Cost per Load
Measure or estimate the electricity used until the load is acceptably dry, then multiply that kWh figure by your electricity unit rate.
The stable calculation is: electricity used for the completed drying session in kWh × your electricity unit rate. If you only have rated wattage, watts ÷ 1,000 × hours gives a rough kWh estimate, but cycling means rated power may overstate or misrepresent actual consumption.
This is more useful than publishing one permanent pence-per-load figure. Tariffs change, dehumidifiers have different power profiles and different loads require different runtimes. Use the site's dehumidifier running-cost calculator for your own wattage, runtime and current rate.
- Best comparison unit: kWh per completed load
- Cost = completed-load kWh × electricity unit rate
- Use actual measured consumption where practical and appropriate
- Include the whole drying session, not just the first few hours
- Do not add the daily standing charge to compare the marginal cost of one appliance session
| Method | Calculation | Main Limitation |
|---|---|---|
| Measured energy | Metered kWh for completed load × tariff | Requires a suitable way to measure consumption |
| Rated-power estimate | Watts ÷ 1,000 × hours × tariff | May not reflect cycling or variable power |
| Internet pence-per-load figure | Fixed published estimate | Can become stale and may not match your appliance or load |
Dehumidifier vs Tumble Dryer
Neither is automatically cheaper for every completed load; tumble-dryer technology, load size and the dehumidifier setup can change the result.
Do not compare a dehumidifier with a single generic 'tumble dryer' cost. Heat-pump, condenser and vented dryers can have materially different energy use. Which?'s 2026 testing found that the cheapest indoor method depends on factors including the amount of laundry, and efficient tumble dryers can be competitive for some loads [S4].
The appliances also solve different problems. A tumble dryer is a dedicated drying appliance. A dehumidifier works with an airer and can also remove excess moisture from the room. If humidity or condensation is part of your reason for buying one, that additional use belongs in the decision, but it does not prove that it is cheaper per laundry load.
- Compare kWh for the same completed laundry load
- Identify the tumble-dryer type before comparing energy use
- Include repeat sessions if an airer load is not dry after the first run
- Consider drying speed, capacity and convenience as well as electricity
- Consider room-moisture control separately from pure laundry cost
Run a Simple Home Drying Test
Use a repeatable load and record the inputs that actually determine your result.
For a useful household comparison, start with a similar washing load and spin setting, hang it in a similar way, record the room conditions and run the dehumidifier until the load reaches the same definition of dry each time. Record the electricity used if you have a suitable measurement method.
Repeat the test if you want a more reliable household average. A single towel-heavy load or unusually cold day should not become a permanent cost claim for every load.
- Record washing load and final spin setting
- Use similar garment spacing on the airer
- Record starting room temperature and humidity if available
- Record total completed-session kWh
- Note visible window condensation or other signs the room is struggling with moisture
Frequently asked questions
How long does a dehumidifier take to dry clothes?
There is no reliable universal number of hours. Drying time depends on the water left after spinning, load size, fabrics, spacing, room temperature and humidity, airflow and the dehumidifier's performance under those conditions.
How much does it cost to dry clothes with a dehumidifier?
Calculate the electricity used for the completed drying session in kWh and multiply it by your current electricity unit rate. A fixed pence-per-load figure can quickly become inaccurate because tariffs, appliances and runtimes differ.
Where should I put a dehumidifier when drying clothes?
Use it in the room containing the airer, but follow your model's instructions for minimum clearances and placement. Keep the air inlet and outlet unobstructed rather than relying on a universal one- or two-metre rule.
Should I close the window when using a dehumidifier for laundry?
If you are deliberately dehumidifying one room, an open window can make the unit work on incoming air as well as laundry moisture. However, do not block permanent ventilation, and remember that a dehumidifier does not supply fresh air. Follow the appliance and building ventilation guidance appropriate to your home [S2][S3].
Is a dehumidifier cheaper than a tumble dryer?
Not automatically. Compare kWh per completed load using your actual appliances. Tumble-dryer type matters, and current comparative testing shows that the result can change with load size and drying method [S4].
Bottom line
A dehumidifier can be a useful indoor-laundry tool because it removes moisture from the room while clothes dry [S1][S2]. The strongest setup is not a magic distance, capacity or runtime: space the laundry, preserve appliance airflow, follow the manufacturer's instructions and manage the room's moisture. For cost, compare measured or estimated kWh per completed load at your current tariff rather than relying on a fixed pence figure.
Sources
Sources are shown so readers can check time-sensitive or factual claims directly.
- S1 Can you use a dehumidifier to dry laundry? — Which?
- S2 How to get rid of damp — Energy Saving Trust
- S3 Understanding and addressing the health risks of damp and mould in the home — UK Government
- S4 What's the best and cheapest way to dry clothes indoors? — Which?