Quick answer: Running cost = average power (kW) × running hours × electricity price. Use measured kWh where you can; otherwise use average power, not nameplate maximum, because compressors and heaters cycle and modulate. Then divide by the water removed to get cost per litre, which is the fair way to compare units. Example: a refrigerant unit averaging 6 kW for 18 hours a day at €0.15/kWh costs about €16 a day; if it removes 300 litres, that is about €0.05 per litre. Over a unit's life, energy is usually the largest cost, so a more efficient unit at your conditions often pays back a higher purchase price.
Quick answer
- Daily cost = average kW × hours × price per kWh.
- Compare units by cost per litre at the same room condition.
- Energy usually outweighs purchase price over the equipment's life.
The formula
Energy (kWh) = average power (kW) × hours, or the meter reading difference. Cost = energy × tariff (sum each tariff period separately if prices vary by time of day). Cost per litre = cost ÷ litres removed in the same period.
Average power is typically below the rated maximum: refrigerant compressors cycle on the humidistat; desiccant heaters may modulate. If you only know maximum power, the result is a conservative (high) estimate.
Worked examples
Refrigerant: RYCF-22S (480 L/day rated at 30 °C / 80 % RH; maximum 8.4 kW)
- Assumed average power at the site: 6 kW, 18 hours a day.
- Energy: 6 × 18 = 108 kWh/day.
- At €0.15/kWh: €16.20 per day.
- If it removes 300 L/day at the site condition: €0.054 per litre.
Desiccant: RY-1000M (180 L/day rated at 20 °C / 60 % RH; 11 kW)
- Assumed running 20 hours a day at full power: 220 kWh/day.
- At €0.15/kWh: €33 per day.
- If it removes 150 L/day: €0.22 per litre.
The desiccant unit costs more per litre, but in a cold store where the refrigerant unit would barely work, it may be the only option. These are illustrations; real figures depend on your conditions.
Annual and lifecycle cost
Annual energy cost = daily cost × running days
Example: the RYCF-22S above for 200 humid days a year: 16.20 × 200 ≈ €3,240 a year.
Lifecycle cost ≈ purchase + installation + (annual energy + maintenance) × years
Over 10 years, energy for such a unit can be several times its purchase price. A unit that removes 20 % more water per kWh at your condition saves about 20 % of that energy bill.
What changes running cost
| Factor | Effect |
|---|---|
| Room temperature and RH | Cooler, drier rooms reduce litres per kWh for refrigerant units |
| Moisture load | More leakage, doors and processes mean longer running |
| Setpoint | Each point lower means more running; 50 % instead of 45 % can cut hours noticeably |
| Unit size | Undersized units run all day and may not reach target; oversized short-cycle |
| Maintenance | Dirty filters and coils raise power per litre |
| Fan power in ducted systems | High duct pressure increases fan energy |
| Heat value | In greenhouses and pools, the heat a refrigerant unit releases offsets heating |
The US DOE's manufacturing energy resources and fan system sourcebook cover efficient fan and system operation (US DOE, Fan sourcebook).
How to measure your actual cost
- Fit a kWh meter on the unit's supply (or read the BMS energy data).
- Measure condensate collected over the same period (tank, pump counter, or flow meter).
- Record room temperature and RH.
- Calculate kWh per litre and cost per litre; repeat across seasons.
Ways to lower running cost
- Seal the space and control doors.
- Set the highest RH that protects the goods or process.
- Keep filters and coils clean.
- Choose the right technology for the temperature: refrigerant for warm spaces, desiccant for cold or low dew points.
- Use heat recovery where the space needs heat.
- Stage several units so each runs at good efficiency.
See dehumidifier energy consumption, desiccant power consumption and commercial dehumidifier cost drivers.
FAQ
Frequently asked questions
How much does it cost to run an industrial dehumidifier?
Average power × hours × electricity price. A unit averaging 6 kW for 18 hours at €0.15/kWh costs about €16 a day.
How do I compare running costs of two dehumidifiers?
Compare cost per litre removed at the same room condition.
Is a desiccant dehumidifier more expensive to run?
Per litre, usually yes in warm conditions; in cold spaces it may be the only effective option.
Sources
- US DOE, Improving Fan System Performance: A Sourcebook for Industry; manufacturing energy guidance.
- Product data: Yakeclimate RYCF and RY specifications.
