How much electricity a dehumidifier uses in a day can be worked out in kWh as "rated dehumidifying capacity (liters/day) ÷ energy factor value (liters/kWh)", and then applied to the progressive electricity tier of your billing period. Taking a 12 liters/day model as an example, under the 2026 new standard of the Energy Administration, Ministry of Economic Affairs, the lower limit of the energy factor value is 1.80 for Grade 5 and 2.74 for Grade 1; the estimated consumption for running 24 hours straight is about 6.67 kWh and about 4.38 kWh respectively, a difference of about 68.6 kWh over a month (30 days). The electricity cost depends on which tier your household's original usage falls in and on how many hours the machine actually runs each day.
This article covers only power use and electricity cost and does not repeat "how many liters for how many ping (1 ping ≈ 3.3 m²)"; for choosing capacity, see How to choose dehumidifier liters.
Understanding the label first: rated dehumidifying capacity and energy factor value
The Energy Administration's notice on the permitted energy consumption benchmark and the energy efficiency grading labelling items, methods and inspection methods for dehumidifiers (除濕機容許耗用能源基準與能源效率分級標示事項、方法及檢查方式), issued by the Ministry of Economic Affairs on November 24, 2023 as notice No. 11258024850 (經能字第 11258024850 號), takes effect after amendment on January 1, 2026. The notice specifies that dehumidifiers are tested for the energy factor value (能源因數值) under CNS 12492, that the measured value must not be lower than the permitted energy consumption benchmark and must be at least 95% of the value labelled on the product; the grade is determined by the labelled energy factor value on the test report, according to the grading benchmark table.
The definition of the energy factor value is in a note to Schedule 1 (附表一) of the notice: after running under standard conditions until equilibrium, it is obtained by "measuring the amount of dehumidified water (liters) and the electricity consumed (kWh) over three hours or more, and dividing one by the other". That is, how many liters of water are removed per 1 kWh of electricity, and the larger the number, the more energy-saving. The schedule also notes "at the present stage, energy factor values are limited to inspecting models with power consumption of 1,000W or less".
Two things to note. First, the energy factor value is measured under standard test conditions; when the temperature and humidity at home differ from the test conditions, the actual efficiency will differ, and this article's conversions are only estimates. Second, the notice is the new standard from 2026; machines labelled in different years do not necessarily have the same grade thresholds, so when comparing, looking directly at the energy factor value is more reliable than looking only at the grade.
How far apart Grade 1 and Grade 5 are: the benchmark table
The table below is Schedule 5 (附表五) of the notice, the dehumidifier energy efficiency grading benchmark table; each cell is the lower limit of the energy factor value for that grade (liters/kWh, "at or above", and below the lower limit of the grade above).
| Rated dehumidifying capacity (liters/day) | Grade 5 | Grade 4 | Grade 3 | Grade 2 | Grade 1 |
|---|
| 6 or less | 1.58 | 1.75 | 1.91 | 2.08 | 2.24 |
| Over 6, up to 9 | 1.80 | 2.00 | 2.20 | 2.42 | 2.60 |
| Over 9, up to 12 | 1.80 | 2.03 | 2.27 | 2.50 | 2.74 |
| Over 12 | 1.96 | 2.21 | 2.47 | 2.72 | 2.98 |
The Grade 5 lower limit is also the permitted energy consumption benchmark in Schedule 1 (the minimum threshold): 1.58 for 6 or less, 1.80 for over 6 to 9 and for over 9 to 12, and 1.96 for over 12. Comparing the lower limits of each grade, a Grade 1 model of the same capacity removes about 42% (6-liter class) to about 52% (over 9 liters) more water per kWh than the Grade 5 lower limit; in terms of consumption, to remove the same day's worth of water, the Grade 1 lower limit uses about 29.5% (6-liter class) to about 34.3% (over 9 liters and up to 12 liters) less than the Grade 5 lower limit. These figures are obtained by dividing two lower-limit values and are not a measurement of any particular machine.
Converting to daily and monthly consumption
The conversion: kWh per day = rated dehumidifying capacity ÷ energy factor value; kWh per month = kWh per day × 30. The table below assumes the machine runs continuously for 24 hours under label conditions and removes exactly the rated amount, plugging in the lower limit of the energy factor value for each grade, so the figures are estimates.
| Rated dehumidifying capacity | Grade 5 lower limit: kWh per day | Grade 5 lower limit: kWh over 30 days | Grade 1 lower limit: kWh per day | Grade 1 lower limit: kWh over 30 days | Difference over 30 days |
|---|
| 6 liters/day | 3.80 | 113.9 | 2.68 | 80.4 | 33.6 kWh |
| 10 liters/day | 5.56 | 166.7 | 3.65 | 109.5 | 57.2 kWh |
| 12 liters/day | 6.67 | 200.0 | 4.38 | 131.4 | 68.6 kWh |
| 16 liters/day | 8.16 | 244.9 | 5.37 | 161.1 | 83.8 kWh |
| 18 liters/day | 9.18 | 275.5 | 6.04 | 181.2 | 94.3 kWh |
This table is a scenario of "running all day, every day", which most households do not do. In practice you can treat the daily kWh as a maximum and multiply it by "the proportion of the day the machine actually runs"; for example, running only 8 hours a day, a rough estimate is one third of the daily kWh in the table. The machine's stops, cycling on and off and humidity changes in actual use are not included in this table, so actual consumption will not be exactly this proportion.
How the electricity cost is worked out: kWh times the progressive tier rates
Residential electricity uses progressive pricing: the more you use, the higher the per-kWh rate for the portion above each threshold. Summer months run from June 1 to September 30 each year, after which the lower non-summer rate resumes (as explained in a 2017 Executive Yuan news item; follow Taipower's current announcements). Taipower's time-of-use estimation page also states that the billing period on an electricity bill is 2 months, and suggests dividing the kWh on the bill by 2 to get the monthly kWh. So the dehumidifier's electricity cost is not "kWh × one fixed rate" but:
- Use this article's formula to work out the extra kWh per month from the dehumidifier.
- Add it to your original monthly kWh to get the new total monthly kWh.
- Following Taipower's rate table, multiply each tier your usage reaches by its unit rate to work out the new electricity cost.
- The new cost minus the original cost is the extra electricity cost from the dehumidifier.
For each tier's unit rate, follow Taipower's latest rate table or your electricity bill; this article lists no unit rates.
How current the rates are: the "approved rates" page in the electricity price information disclosure section of the Energy Administration, Ministry of Economic Affairs says that the unit rates applicable to each type of electricity use were approved by the Ministry of Economic Affairs on September 26, 2025 and take effect from October 1, 2025. The review committee meeting resolved on March 27, 2026 that rates would not be adjusted, and the review committee meeting on September 18 resolved to postpone the decision on this rate adjustment, leaving it to be discussed at the 3rd review committee meeting in December of that year. So the unit rates are as announced on 2026-11-07 and may change after the end of the year.
For Grade 1 versus Grade 5 of the same machine, the electricity-cost gap is "the kWh gap × the unit rate of the tier you are in". Taking the 12-liter class above as an example, running all day for 30 days, the Grade 1 lower limit uses 68.6 kWh less than the Grade 5 lower limit, and you multiply by whatever the per-kWh rate is; running 8 hours, the daily kWh is one third of the table figure, and the gap also shrinks to one third. The gap between grades only widens if the machine runs for a long time; if you run it only in the humid few months of the year, the electricity cost saved has to be compared with the price difference between the two machines.
This calculation can be plugged into the appliance electricity cost calculator; for the basic way to convert wattage to kWh, see How many kWh does an appliance use in an hour? Converting watts to kWh and electricity cost.
Reading the annual consumption on the label page: two real examples
The approved-product pages of the Energy Administration's energy efficiency grading label management system (能源效率分級標示管理系統) list each model's rated dehumidifying capacity, energy factor value, product efficiency grade and annual consumption. The two entries below are registrations under the 2026 new standard, opened on 2026-11-07, and serve only as examples of "how to read the label", not as a recommendation.
| Model | Rated dehumidifying capacity | Energy factor value | Efficiency grade | Annual consumption (label page) | Daily kWh by the formula above |
|---|
| DH1200 | 12.0 liters/day | 2.8 liters/kWh | Grade 1 | 96 kWh/year | 12.0 ÷ 2.8 ≈ 4.29 kWh |
| BE-10BH | 10.0 liters/day | 1.8 liters/kWh | Grade 5 | 125 kWh/year | 10.0 ÷ 1.8 ≈ 5.56 kWh |
Note the annual consumption figures. The 125 kWh/year labelled for BE-10BH is only about 0.34 kWh a day on average, far below the 5.56 kWh of running 24 hours continuously; if it ran all day every day, a year would be 5.56 × 365 ≈ 2,028 kWh. The label page does not state the usage-hour assumption behind the annual consumption, and this article did not find it on the pages it opened. Back-deriving from these two entries, the annual consumption is about the consumption of "running the rated dehumidifying amount continuously for about 22.5 days" (96 × 2.8 ÷ 12.0 ≈ 22.4; 125 × 1.8 ÷ 10.0 = 22.5; back-derived, not an official explanation). So do not take the labelled annual consumption as your all-day consumption; recompute it yourself using daily kWh and your actual running hours.
Running all day or on a timer, and how air-conditioner dehumidify mode compares
The difference between running all day and running on a timer mainly depends on what humidity you want to bring it down to, how well the room is ventilated, and whether laundry is dried indoors; for humidity targets, see What indoor humidity to maintain and how to choose the dehumidifier target setting. On the electricity side the principle is simple: for the same machine, the shorter it runs, the fewer kWh, and a higher-grade model saves more over the same running hours.
As for "which uses more electricity, air-conditioner dehumidify mode or a dehumidifier", this article found no official data from the Energy Administration or the Bureau of Standards, Metrology and Inspection (BSMI) (標準檢驗局) that allows a direct comparison, so it gives no multiple. If you want to compare yourself, find the power consumption on the nameplate or the manufacturer's manual and the dehumidifying amount per hour for each, convert to kWh with the same formula "power × time ÷ 1000", and then compare how many kWh each uses per 1 liter of water removed.
FAQ
About how much does a dehumidifier cost to run for a day?
Work out the kWh first and then the money: kWh = rated dehumidifying capacity ÷ energy factor value × running hours ÷ 24 (assuming that it runs under label conditions throughout the running time). For example, for a 12-liter-class model with an energy factor value of 2.74, running 8 hours is about 1.46 kWh; then see which tier your billing period falls in and plug in the corresponding unit rates from the rate table, and do not multiply by a single "average rate".
Is Grade 1 efficiency really more energy-saving?
Comparing the lower limits in the benchmark table, a Grade 1 model of the same capacity uses about three-tenths less electricity per liter of water removed than a Grade 5 model; but you have to run it long enough for the price difference to pay back; this is a comparison of lower limit against lower limit, and a real machine may be higher or lower (for example, DH1200 has an energy factor value of 2.8, which uses about 36% less than the Grade 5 lower limit of 1.80). In addition, the labelled grade is determined by the energy factor value and does not represent your home's actual power use, and when reading the annual consumption you should also watch its usage-hour assumption.
Why is my dehumidifier's actual power use different from what I calculate?
The energy factor value is the result of measuring over three hours or more under standard conditions; the temperature and humidity at home, the machine stopping, and the compressor cycling on and off all change the actual power use, so this article's conversions are only estimates. To find the actual figure, use a plug-in socket-type electricity meter to measure the kWh over a period; do not open up the machine or an extension cord to measure.
Do the electricity tiers affect the dehumidifier's electricity cost?
Yes. Residential rates are progressive: the more you use, the higher the per-kWh rate for the portion above each threshold, and the summer rate is higher than the non-summer rate. If your home already uses a lot of electricity, the kWh the dehumidifier adds will fall in a higher tier, and the same kWh then cost more.
Sources
- Energy Administration, Ministry of Economic Affairs, energy efficiency grading label management system: notice on the permitted energy consumption benchmark and the energy efficiency grading labelling items, methods and inspection methods for dehumidifiers (verified 2026-11-07) (in Chinese): notice of November 24, 2023, in effect from January 1, 2026; CNS 12492; measured values must be at least 95% of the labelled value
- Schedule 1 of the same notice: permitted energy consumption benchmark for dehumidifiers (verified 2026-11-07) (in Chinese): the energy factor value benchmark for each capacity, the note defining the energy factor value, the limit to models of 1,000W or less
- Schedule 5 of the same notice: dehumidifier energy efficiency grading benchmark table (verified 2026-11-07) (in Chinese): lower limits of the energy factor value for Grades 1 to 5
- Energy Administration approved products: model DH1200 (verified 2026-11-07) (in Chinese): rated dehumidifying capacity, energy factor value, grade, annual consumption
- Energy Administration approved products: model BE-10BH (verified 2026-11-07) (in Chinese): rated dehumidifying capacity, energy factor value, grade, annual consumption
- Energy Administration, Ministry of Economic Affairs, electricity price and rate review information disclosure section: approved rates (verified 2026-11-07) (in Chinese): unit rates take effect from October 1, 2025
- News releases section of the same disclosure section (verified 2026-11-07) (in Chinese): review committee resolutions of 2026-03-27 and 2026-09-18; the news release of 2025-09-19 says "for residential rates, progressive pricing is mostly used"
- Executive Yuan website: summer rates start on June 1 as usual (verified 2026-11-07) (in Chinese): the summer rate period is June 1 to September 30, and from October 1 the lower non-summer rate resumes (news of 2017-05-24)
- Taiwan Power Company (Taipower) time-of-use rate estimation for metered lighting customers (verified 2026-11-07) (in Chinese): summer months are June to September, the billing period on an electricity bill is 2 months
