A dehumidifier removes excess indoor moisture, and usually collects it in a removable plastic bucket. How much water should a dehumidifier collect in a day? We can estimate that quite well by looking at the dehumidifier capacity. Let’s look at how to estimate daily dehumidifier water collection adequately (you can also check the daily dehumidifier water collection chart further on):
Namely, we have 20-pint, 30-pint, and 50-pint portable dehumidifiers and 70-pint and up to 170-pint whole-house dehumidifiers. These dehumidifier dehumidification rates offer us a key insight into how much water a dehumidifier should collect in a day (the devil is in the details, however; we’ll explain that).
Simple Example: A 50-pint dehumidifier should collect 50 pints of water per day (that’s 6.25 gallons of water per day). On an hourly basis, that is 2.08 pints of water per hour. If you have a 2.5-gallon bucket, you can expect to empty it 3 times per day.
Do all 50-pint dehumidifiers collect 50 pints of water per day? Of course not. A 50-pint dehumidifier will collect 50 pints of water per day only if we run it 24 hours per day at 65°F temperature and 60% relative humidity levels. It can collect as little as 30 pints or even more than 90 pints per day.
To pinpoint how much water will dehumidifier collect daily, we first have to understand how the dehumidifier’s dehumidification rate (capacity) is measured, in accordance with the US Department Of Energy (DOE) test conditions.
To help everybody out, we have created an expected daily dehumidifier water collection chart for 20-170 pint dehumidifiers. You will find this chart further on.
How Dehumidification Rate Or Dehumidifier Capacity Is Measured?
Dehumidifier capacity is a key specification that tells us how much water a dehumidifier should collect in a day (expressed in pints/day). Now, it is very important to understand how this daily water collection capacity is measured.
Namely, the DOE determines the test condition at which we measure how much water a dehumidifier should collect on a daily basis. Currently, we have two standards – the old and the new:
- Old 2019 and prior standard. The dehumidification rate is measured at 80°F temperature and 60% relative humidity.
- New 2020 current standard. The dehumidification rate is measured at 65°F temperature and 60% relative humidity. Here is the DOE 10 CFR 430, Subpart B, Appendix X1 document that specifies these test conditions.
The only difference here is that the new dehumidification capacity is measured at 65°F temperature, not at 80°F. This change is largely because DOE deems many residential dehumidifiers are used in basements that have lower temperatures (closer to 65°F than to 80°F).
That’s why we have seen a change in dehumidifier capacities from 2019 to 2020, as summarized by Energy Star here. Here are a few examples:
- Old 70-pint dehumidifier is now a 50-pint dehumidifier.
- Old 50-pint dehumidifier is now a 30-pint dehumidifier.
- Old 30-pint dehumidifier is now a 20-pint dehumidifier.
Now, the key takeaway here is this:
If we run a 20-pint dehumidifier at 65°F temperature and 60% relative humidity for 24 hours per day, we can expect to collect 20 pints of water per day (2.5 gallons of water per day).
What is we don’t use a dehumidifier in a room with 65°F temperature and 60% relative humidity?
65°F temperature and 60% relative humidity is a lab-based measurement. In practice (in our homes), we will obviously have different temperatures (60°F, 65°F, 70°F, 75°F, 80°F, etc.) and different humidity levels (50%, 60%, 70%, 80%, even 90%).
Here are 2 key rules to remember:
- If we run a dehumidifier at higher than 65°F temperature, the daily water collection will be higher than specified. Example: A 30-pint dehumidifier can collect 38 pints of water per day at 74°F temperature.
- If we run a dehumidifier at higher than 60% relative humidity, the daily water collection will be higher than specified. Example: A 50-pint dehumidifier can collect 68 pints of water per day at 80% relative humidity.
Example: If you run a dehumidifier at a very high temp and RH (let’s say 85°F and 90% RH), you can expect that the dehumidifier will fill up every few hours.
Based on these two rules and the old DOE measurements, we can construct a chart that will tell us how much water a dehumidifier can collect per day:
Daily Dehumidifier Water Collection Chart
|Dehumidifier Capacity||Daily Water Collection (65°F, 60% RH):||Daily Water Collection (80°F, 60% RH):|
|20-Pint Dehumidifier||20 Pints Per Day (2.5 Gallons/Day)||30 Pints Per Day (3.8 Gallons/Day)|
|25-Pint Dehumidifier||25 Pints Per Day (3.1 Gallons/Day)||40 Pints Per Day (5.0 Gallons/Day)|
|30-Pint Dehumidifier||30 Pints Per Day (3.8 Gallons/Day)||50 Pints Per Day (6.3 Gallons/Day)|
|35-Pint Dehumidifier||35 Pints Per Day (4.4 Gallons/Day)||55 Pints Per Day (6.9 Gallons/Day)|
|50-Pint Dehumidifier||50 Pints Per Day (6.3 Gallons/Day)||70 Pints Per Day (8.8 Gallons/Day)|
|70-Pint Dehumidifier||70 Pints Per Day (8.8 Gallons/Day)||80 Pints Per Day (10 Gallons/Day)|
|85-Pint Dehumidifier||85 Pints Per Day (10.6 Gallons/Day)||100 Pints Per Day (12.5 Gallons/Day)|
|100-Pint Dehumidifier||100 Pints Per Day (12.5 Gallons/Day)||120 Pints Per Day (15 Gallons/Day)|
|115-Pint Dehumidifier||115 Pints Per Day (14.4 Gallons/Day)||140 Pints Per Day (17.5 Gallons/Day)|
|135-Pint Dehumidifier||135 Pints Per Day (16.9 Gallons/Day)||160 Pints Per Day (20 Gallons/Day)|
|170-Pint Dehumidifier||170 Pints Per Day (21.3 Gallons/Day)||200 Pints Per Day (25 Gallons/Day)|
As we can see from the chart, 20-pint to 50-pint portable dehumidifiers collect:
- 2.5 to 6.3 gallons of water per day at lower 65°F and 60% relative humidity levels.
- 3.8 to 8.8 gallons of water per day at higher 80°F and 60% relative humidity levels.
Bigger 70-pint to 170-pint whole-house ducted dehumidifiers collect:
- 8.8 to 21.3 gallons of water per day at lower 65°F and 60% relative humidity levels.
- 10 to 25 gallons of water per day at lower 65°F and 60% relative humidity levels.
Using this chart, you can now adequately estimate how much water should your dehumidifier collect per day. Do remember that at higher temperatures and higher relative humidity levels, the daily water collection can exceed these numbers. If you have any questions regarding dehumidification rates, you can give us some numbers in the comments below, and we’ll help you out.