The short answer
There is no honest universal cost winner. A 200 W dehumidifier running for eight hours uses 1.6 kWh; a dryer using 1.2 kWh in a completed cycle would cost less despite drawing more power while active. Reverse either runtime and the answer changes.
Use the energy-per-cycle figure on the dryer's current energy label or measure a representative cycle where safe. For the dehumidifier, a plug meter captures compressor and fan cycling over the complete room-drying period. Multiply both by the same electricity price.
Illustrations are not tariff claims. Enter your actual pence-per-kWh figure in our calculator and use measured kWh wherever possible.
Run a fair home comparison
Use two similar loads with the same dry-fabric mass and the same washing-machine programme and spin speed. Weigh each immediately after spinning if you can. Do not compare towels in one test with lightweight synthetics in another.
Define the finish before starting: cupboard-dry, ready to iron or no item above a chosen moisture check. Record total elapsed time, active attention and any items that remain damp. Convenience is part of the outcome even when it is not an energy unit.
- Record the dryer's cycle and displayed or measured kWh.
- Record dehumidifier watt-hours for the complete load, including cycling.
- Note room temperature, rack layout and whether doors or windows stayed closed.
- Repeat each method before trusting a close result.
Dryer technology changes the comparison
A heat-pump tumble dryer recovers heat and is a different energy proposition from older vented or condenser designs. Capacity, programme, moisture sensor accuracy, maintenance and load type also change actual consumption. Use the specific model's label rather than a generic internet average.
Clean filters and heat exchangers as instructed. Poor maintenance can lengthen cycles. If a vented dryer exhausts indoor heated air, a simple appliance reading may not capture the whole-home heating effect during winter.
The dehumidifier is drying a room as well as clothes
A rack method releases water into room air, then the dehumidifier removes it. The appliance may also reduce background room moisture, which is a useful extra outcome but makes a strict appliance-only comparison harder.
Keep the room controlled, space garments, use a high washer spin and aim the permitted airflow through the rack. Opening a window while the machine runs can turn the test into an uncontrolled exchange with outdoor air.
A worked method without a fake tariff
Suppose your plug meter reports 1.45 kWh for the room method and the dryer's label or meter reports 1.10 kWh for the matched load. Multiply each by your current unit rate. At any tariff, the 1.10 kWh result costs less for that load; the actual currency amount changes with the tariff.
Then consider what the numbers exclude: purchase price, rack space, appliance wear, fabric care, time and whether the room needed humidity control anyway. Keep energy and preference separate so neither is disguised as evidence.
When each method makes sense
A dehumidifier-and-rack routine can suit homes already managing indoor moisture, people avoiding high fabric temperatures and loads that can wait. A tumble dryer suits fast turnaround and contained drying, especially when an efficient heat-pump machine is already owned.
The cheapest new purchase is often no purchase: improve washer spin, fully load an existing efficient appliance and measure the current method before replacing it.
Common questions
Questions this guide should answer
Is a dehumidifier cheaper than a tumble dryer?
It can be, but not always. Compare total kWh for matched completed loads. A long dehumidifier run can use more energy than an efficient heat-pump dryer cycle.
How do I calculate laundry drying cost?
Multiply the measured kWh for the complete load by your electricity unit price. Do not multiply peak watts by an assumed runtime if a meter or energy label is available.
Does a dehumidifier heat the room?
It releases electrical energy and latent heat back into the room, so outlet air is usually warmer. That effect is part of the room system, not free energy.
Should I include the cost of heating the room?
Include it if the heating schedule differs between methods. If the room would be heated anyway, state that assumption rather than assigning the full heating cost to laundry.
Sources and review trail
We favour primary public guidance and link to the exact source so you can inspect it yourself.