This is How Long it Takes Dehumidifiers to Dry a Room

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Accidents happen, and unfortunately, they always seem to occur when we aren’t ready, prepared, or genuinely in a place to handle them with anything one might consider easy. 

Thankfully when a room experiences a flood, breakage, or anything that might leave it damp, there is a quick and simple solution.

Utilizing a dehumidifier can make what might be a several-day endeavor for mother nature to run its course. That raises a relatively important question; it may be faster without a doubt, but how long does it take for a dehumidifier to dry out a room? 

It takes a dehumidifier a few days to completely dry a room out. However, having the room dried depends on a few things: the size of a dehumidifier, the size of the room, and how humid the area is.

For example, if you have a large and humid room, you’ll need a dehumidifier that fits the criteria of that space.

In this article, we will be delving into multiple topics, ranging from how long it takes to dry a dehumidifier out to what size you need. Read on to find out all there is to know on the subject!

How Long Does it Take for a Dehumidifier to Dry Out a Room?

The answer to this question varies depending on a couple of circumstances you are dealing with:

Let us go more in-depth on them down below. 

1. The Size of the Dehumidifier

Suppose you were to get a dehumidifier that isn’t large enough. In that case, it could take longer to dry the room out than advertised. 

On the other end of the scale, you can get one too large and handle the initial problem very well, but won’t be practical for anything else afterward.

2. It Depends on the Capacity & Size

All dehumidifiers come in various sizes and have a maximum capacity of moisture they can remove from the air. The excess water released from the perspective is stored in a removable tank inside the unit. 

Side note: Some units feature a drainage mode. This drain mode can have a hose connecting to the tank itself that you can, in turn, constantly drain to a nearby drain or other openings.

How to Tell the Correct Size of My Heater

To know the correct size of dehumidifier you will need, you will want first to find out precisely how humid the room is. To answer that question, you will need to use a hygrometer. 

A hygrometer will tell you how damp the room is. Using that information, you will combine it with the square foot size of the room and shop for a dehumidifier that will suit your needs perfectly.

Assuming you do the above and place your dehumidifier in a spot that gives it considerable airflow, you can expect the room to be arid within two or three days. Of course, this is if the damage source is not an ongoing issue.

How to Get Rid of Excess Moisture in the House

Having a dehumidifier will combat most of the moisture affecting the room by itself. Still, you can take the fight in your hands with a few quick and easy tricks. 

The first is taking the initiative to carefully inspect your home for any possible leaks or openings where humidity might be able to seep in.

You will have to be a little creative in your search. Still, the most common locations would be around windows and doors. Other areas within the home where humidity can seep in are ventilation areas for dryers, ovens, etc. 

Some other less common practices could range from the following:

  • Opening your windows to get some fresh air and sunlight in.
  • Installing fans around your home that helps circulate the airflow directly.
  • Depending on which method you are utilizing, the dehumidifier or out a window.

Best Place to Put a Dehumidifier When Drying an Area?

1. Place the Dehumidifier in the Middle of the Room

If you attempt to dry out one room, your best bet is to ensure all windows and other areas in the house are sealed off. You will then want to place the dehumidifier directly in the middle of the room you attempt to air out. 

Doing so will maximize the effort of the dehumidifier to that room and expedite the process immensely. It’s worth noting more heavily waterlogged rooms may require you to empty the water storage tank at regular intervals to ensure the unit is working around the clock.

2. Check Out Heavy-duty Options

One final bit of advice here would be to take the time to check if your dehumidifier has “heavy-duty” options. 

A heavy-duty option may include anything from a laundry mode to cranking the capacity to the maximum. Either way, doing so will allow you to get the job done in as short amount of time as possible.

We have created a chart that might better help you out in deciding what size to get and have gone more in-depth on the subject down below as well: 

800+ sq. ft.1500+ sq. ft.2000+ sq. ft3500+ sq. ft
Normal20+ pints25+ pints35+ pints50 pints
Slightly damp20 pints30 pints35 pints50 pints
Very damp25 pints35 pints40 pints50 pints
Wet30 pints40 pints45 pints70 pints
Extremely wet35 pints40 pints50 pints70 pints

3. Enclosed Area

Areas of your room that are deemed more undersized, like closets, attics, crawlspaces, and things of that manner, would be considered enclosed. You won’t need to break the bank on a larger dehumidifier to accomplish the same job. 

In most cases, you won’t have to get something more significant than a 13+ pint dehumidifier because it is such a small area to cover. This dimension will still overcompensate to some extent and guarantee even the walls and roof are free of any potential mold.

4. Open Area

Larger areas can be a tad trickier. However, you will want to take the time to measure your room before purchasing your dehumidifier to ensure you are well taken care of. Getting the unit that can handle the job at hand is very crucial. 

You can most definitely make do with a pre-existing dehumidifier if you had one laying around or purchased the wrong one already. Still, the process will take longer to do because a smaller dehumidifier will struggle to meet its exact demand.

In the long run, this will damage the unit itself if done routinely and cost you quite a bit of money if you deal with flooding or something similar almost year-round. In that case, take some time and do the research required to handle issues accordingly. 

One final thing to be aware of is that various dehumidifiers handle other rooms, specifically if you wanted to delve just a bit deeper into that territory. Still, the general rule of thumb is that square feet determine the size you need. Anything else is preferred.

How Long Should I Run a Dehumidifier?

The amount of time required to run the dehumidifier depends entirely on the abovementioned criteria. If you’ve taken your time and gotten everything up to par, the room you are attempting to dry should return to normal in about two days. 

Almost all dehumidifiers come with a built-in auto-off feature that will cause the unit to power down once the desired humidity level has been achieved. You won’t have to worry about the dehumidifier running for too long or too little. 

Should I Close the Door When Using a Dehumidifier?

Truthfully closing the door, or conversely opening it, is of little consequence to the job of drying out a room. Be wary of combining efforts on opening doors that lead outside or, by the same token, opening windows.

Making the room accessible to outside air causes an unstable influx of airflow that completely defeats the purpose of using a dehumidifier in the first place. 

The unit is designed only to regulate humidity within a particular space (that square foot measurement we spoke of earlier). Anything more than that will cause the device to work in-efficiently.

Considering the above, you always want to ensure you have closed all doors and windows leading outside to finish the job. You give yourself and the dehumidifier by association a fighting chance to succeed at the task.


Assuming you don’t have an ongoing issue and purchased the correct size dehumidifier for the job, you can have your room dry in roughly two days. 

Still, suppose you are combating an ongoing issue like a leak or formidable climate that causes flooding. In that case, you may want to seek some more permanent solutions.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.