Does A Dehumidifier Work With The Windows Open?

Dehumidifiers are great for dealing with moisture in a variety of places, but they can lose effectiveness quickly if not used within a tighter and more sealed environment.

Opening windows and doors to the room in which a dehumidifier is operating may seem like the extra ventilation can help but a dehumidifier can work more effectively when it doesn’t have to deal with further humid air.

The windows in a room should be kept closed when running a dehumidifier. As open windows let moisture in from the outside, they can work against the dehumidifier and keep the room from drying out because the continuous flow of air can be counterproductive.

While a dehumidifier can work with the windows open, there seems to be very little reason why they should.

We always leave our windows closed in the room we’re dehumidifying.

Keeping the windows closed can help a dehumidifier to work more efficiently

For more details about how dehumidifiers work and why open windows may be a poor choice, read on below.

Do Open Windows Work Against A Dehumidifier?

While open windows won’t stop a dehumidifier from working, they will, at the least, reduce its effectiveness.

This is for a few reasons, but it may be helpful to start with an analogy: keeping a dehumidifier working with open windows is like driving around with the AC on and windows open.

So while it will not do any harm, it is a waste – and ultimately a worse decision.

They work against each other because:

  • The air outside the room may be moister than the air in the room.
  • There is more air to dehumidify.
  • There is more area to cover.

Most important among these reasons is the fact that you cannot control the outside air.

Most of the time, if you need a dehumidifier in a room, the outside air is just as moist. The only real exceptions to this are winter, early spring, or late fall – times when the air outside is too cool anyway. 

Ultimately, this means that keeping the windows open will cause your dehumidifier to work more.

Having more air to cool leads to the same outcome. With open windows, you are guaranteed at least some additional airflow and circulation.

While airflow and circulation help get rid of moisture on their own, they also introduce more air into the inside environment.

Dehumidifiers work best in a sort of “closed-loop system,” where the same air stays in.

The owner’s manual to our dehumidifier explains:

Use the dehumidifier in an enclosed environment for maximum efficiency. Close all external doors and windows to create an effective operating environment.’

Dehumidifier Plugged In
Dehumidifiers can be more efficient working in smaller spaces closed off from the outside and other parts of the house

There’s no need to worry about airflow if you have a dehumidifier running.

While it may not be a lot, the pull and push of air into the dehumidifier means that air will not become too stagnant. If you are worried about that, it is better for the system to run a fan instead.

Finally, having the windows open simply means there is more air for the dehumidifier to cover.

It’s similar to keeping all the doors open in the house – if only the basement needs lower humidity, you are needlessly straining the system.

Windows open up the air even more than doors, however. It basically covers all the air outside!

Keep the windows closed and limit the area that needs to be dehumidified for the best results.

Should I Use A Dehumidifier Or Leave My Windows Open?

While they should rarely be used together, either method can actually help reduce humidity in a room.

To use the car analogy once again, it is similar to choosing between turning on the AC and opening the windows.

Either can cool you down, but one is probably more effective.

Dehumidifiers are the better option for quickly dehumidifying a room and controlling moisture. Still, both have their pros and cons, and it may even come down to personal preference.

For either option, you should consider a few different factors. These include:

  • Your climate
  • How often the area is damp
  • The season
  • Energy costs
  • Air quality

A strong answer in either direction to any one of these categories – for example, extremely wet seasons or high energy costs – can swing your decision strongly to one option. We’ll cover how each of these fit into each system as we cover their benefits and drawbacks.

Finally, remember that you can switch between the two systems easily.

While it’s probably not a good decision to do so constantly, you can decide based on local weather patterns and temperature preferences. After all, like cooling down a car, windows may be nicer than AC on some days.

What A Dehumidifier Offers

Dehumidifiers are an almost guaranteed way of dealing with growing moisture in an area. Their biggest benefit is their consistency; assuming you purchase a unit large enough for the area, it will be effective.

Other benefits include:

When reduced to their essence, all the benefits combine into one: Dehumidifiers are a guaranteed solution that offers fine control over external factors.

This is nice for a variety of reasons. For example, you do not have to worry about coming home one day to find mold growing after it has disappeared just because the weather changed.

Modern dehumidifiers also include the option for you to choose the moisture percentage of the air to ensure that it does not become too dry. This is fantastic for everyone, as dry air can be just as uncomfortable as moist air, but offers extra uses, too.

We can set the target humidity on our dehumidifiers for the most comfortable environment

Wine cellars, for instance, are often kept at specific humidity levels to ensure the drink’s quality. 

Of course, this extra control and tech-based nature of dehumidifiers come with a few drawbacks:

  • Harder setup
  • Electricity costs
  • Initial cost
  • Maintenance

Setting up most dehumidifiers shouldn’t be a difficult task – it is just hard to beat the simplicity of opening a window and walking away. The main downsides are the extra costs you will incur by running a dehumidifier, especially if the area is particularly damp.

Dehumidifier Controls
Dehumidifiers can start at the press of a button if already on the right settings

Plenty of modern units focus on energy efficiency, but you will pay for it when the dehumidifier is on. Consider how often you will have the unit running, what moisture level you are looking for, and your energy costs.

The unit itself also costs money, and this can vary wildly. Small units for cooling down a few hundred square feet of space are relatively cheap, while whole house units are, as expected, quite expensive. You may need to foot a hefty bill to reap the benefits of controlled air.

Finally, every dehumidifier requires some level of maintenance. Usually, this is as simple as removing the water when it fills or setting up an automatic drain, but this can change between units.

What Windows Bring To the Table

Open windows are a great option for more milder cases of moist air.

While they come with their fair share of drawbacks, nothing beats their simplicity and melding of air. Some of the key benefits include:

  • Easy setup
  • No initial cost
  • Increased airflow

The setup and no initial cost are self-explanatory. Your house already has windows – at most, you may need to replace a few screens to get started with open windows for air control.

You also do not need to deal with any technology or set up anything new – just crack the window open, and you’re all set.

Increased airflow really does not affect the humidity of a space, but it can make it more comfortable in general. While not always applicable due to weather changes, a nice breeze can improve a space.

Of course, there are plenty of drawbacks too. These include:

  • No control
  • Seasonal usability
  • Less effective

Open windows to control humidity will never be as effective as a dehumidifier.

Not only is the air outside going to have moisture, but it is simply not dealing with the problem. Open windows do not deal with the moisture in the air – instead, you just hope the more moist air is removed.

This brings us to the other negatives: you have no control over whether or not the system works, and you do not want the windows open when it is cold or rainy. Windows are a great option on dry, cool days with nice airflow but not a great humidity solution. 

Does A Dehumidifier Work With The Windows Open?

Dehumidifiers work best with the windows closed, as opening them can operate counter-intuitively.

While either method can help with reducing humidity in an area, a dehumidifier will simply be made less effective by open windows. You can imagine it like running the AC in a car with the windows open.

Both methods have their benefits and drawbacks, but a dehumidifier is generally the best option. Open windows can help if the conditions are right and you are looking to change the air only mildly.

Further Reading

Can A Dehumidifier Run Constantly?

Should A Dehumidifier Be On All The Time?

Do You Need A Dehumidifier For Every Room?