The dehumidifier (like this one) vs open window debate is an age-old question and one that many of our readers have asked. People ask if they can replace using a dehumidifier simply by opening the windows? Today we’re going to explore this question and finally see which is better.
If you are using a dehumidifier, you should keep the windows closed.
This is because an open window will make your dehumidifier work harder by letting in moist air from the outside. However, if you don’t have a dehumidifier then opening the windows is one of your best options for drying out a room. Think of it like this, when the windows are shut, the dehumidifier only needs to dehumidify the air in the room. If the windows are open though, you are basically asking your dehumidifier to dehumidify the whole atmosphere! It is similar to opening the windows of your car when the air con is on, it is a waste.
Meaco Portable Dehumidifier DD8L
Which? Best Buy 2014/2015/2016
Which is Best for Reducing Humidity?
Both can play valuable roles in dehumidifying a room, but the dehumidifier is the superior option. Opening windows is all well and good in summer, but what about winter? Who wants to have to keep their windows open in winter? Particularly in wet places like the UK! The dehumidifier allows you to dehumidify a room without letting our warm air and letting cold air in. We have produced a lengthy buyers guide reviewing all the top dehumidifiers here.
Open Windows
Opening the windows is a cheap and easy way to dehumidify a room. It can be the easiest way to rapidly dehumidify a room, particularly in summer. However, as we said earlier, it is a different story in winter. During the wet winter months, the humidity outside will also be relatively high. The consequence of this is that opening windows will take a long time to dry out a room. During this time you are also letting out warm air and letting cold air in. This is a good way to waste a lot of electricity that went into heating your home.
Dehumidifier
Dehumidifiers are a tried and tested way of rapidly dehumidifying a room. A large dehumidifier (like Newentor) will be a much more effective way of drying out a room than opening the windows, particularly in winter. The downside of a dehumidifier is that it consumes electricity and requires an initial investment when purchasing one. Despite this though, there are many models of dehumidifier which are energy-efficient, with 12L models using as little as 160 watts.
If you have particularly severe damp issues and mould has begun to grow, then you are past the stage of fixing it with ventilation and we strongly recommend purchasing a dehumidifier. A side benefit of a dehumidifier is that drier air is easier to heat, and some models actually blow out warm air.
Pro Breeze 1000ml Dehumidifier
Auto Shut-Off, LED Light, Portable Mini Air Dehumidifier for Damp, Mould and Moisture in Kitchen, Bedroom, Bathroom, Caravan, Garage, Basement
Will a dehumidifier work with windows open?
Not really, it may work a little bit in a, particularly damp room if the windows are only cracked open. The reason they don’t work with the window open is that as the room dries out, it will naturally attract moist air from outside. This moist air will then bring the humidity level of the room back up, in a similar manner to osmosis. You are basically asking the dehumidifier to dehumidify an infinite amount of air.
Should you close the door with a dehumidifier?
This depends, as long as the windows are shut it shouldn’t be a problem. In the same way as before though, if the doors are open and windows are open in other areas of the house, it might hamper the effectiveness of your dehumidifier. If the damp problem is local to one room, we recommend shutting doors and windows for maximum results. You can leave the doors open though if you are using the dehumidifier to keep humidity down throughout the house. You may also want to close the door if you are using the dehumidifier to dry laundry. This will greatly speed up the process, we have previously covered how the dehumidifier can be a great alternative to the tumble dryer here.
CONOPU Dehumidifier
- Dual semiconductors refrigeration technology for double dehumidifying effect
- Safely and efficiently removes moisture in spaces up to 500 Sq.ft
- Auto defrosting mode prevents freezing in winter
- 3 different modes: Strong, Sleep, and Auto
- Timer and auto-off features for safety and convenience
- 2.3L detachable water tank with 800ml capacity per day
- Easy to clean and maintain
- Strong and Auto modes can be noisy, but Sleep mode is quieter
How long does a dehumidifier take to dry a room
The time it takes for a dehumidifier to dry a room depends on several factors, such as the room size, humidity level, temperature, and the dehumidifier’s capacity. Here are general estimates:
1. Mild Humidity (50-60%)
- A standard dehumidifier might take 2–4 hours to noticeably reduce moisture in a moderately sized room (e.g., bedroom or living room).
2. High Humidity (70-80%)
- Drying a damp or very humid room could take 6–12 hours or more, especially if dealing with excess moisture from drying laundry or a recent water spill.
3. Extremely Damp Conditions (Over 80%)
- In cases like post-flooding or persistent dampness, it might take 24–48 hours of continuous operation to bring the room to a comfortable humidity level.
Factors That Influence Drying Time
- Room Size: Larger rooms take longer to dry.
- Dehumidifier Capacity:
- Small dehumidifiers (10–20 pints/day) are slower.
- High-capacity units (30–50 pints/day) are faster.
- Air Circulation: Improved airflow speeds up drying; use fans if possible.
- Temperature: Dehumidifiers work best in warm environments (above 15°C).
- Ventilation: Closed windows and doors help focus on the room’s humidity.
Quick Tip
Use a hygrometer to monitor the room’s relative humidity. A dehumidifier typically aims for a 40–60% RH range. Once achieved, it will cycle off or you can stop it.
Does Opening Windows Reduce Humidity?
Yes, opening windows can reduce humidity, but it depends on the outdoor conditions. Here’s how it works:
When Opening Windows Reduces Humidity
- Dry Outdoor Air: If the air outside is dry (low humidity), opening windows allows the moist indoor air to escape and brings in drier air, reducing indoor humidity.
- Example: Cool, crisp days with low relative humidity.
When Opening Windows Might Increase Humidity
- Humid Outdoor Air: If the outdoor air is humid (e.g., rainy or muggy weather), opening windows can bring more moisture inside, increasing indoor humidity.
- Example: Warm, rainy days or during summer in humid climates.
Best Practices for Reducing Humidity with Windows
- Choose the Right Time: Open windows during dry, cool weather (often mornings or evenings in the UK).
- Ventilation: Pair open windows with fans or extractor fans to enhance air circulation and moisture removal.
- Close During Humid Weather: Keep windows shut and use a dehumidifier or air conditioning to manage humidity on damp or humid days.
Additional Tips
- Use a hygrometer to measure indoor and outdoor humidity. Aim to keep indoor relative humidity between 40-60% for comfort and mold prevention.
- Consider using trickle vents or keeping interior doors open to improve airflow without fully opening windows.
By managing when and how you open windows, you can effectively control indoor humidity.
Final Thought
Leaving the windows open is an easy way to reduce the effectiveness of a dehumidifier. Closing them will greatly improve results and help you dehumidify your home faster. For minor issues such as mild condensation, opening the window will work fine. For more severe damp moisture problems, however, a dehumidifier can be an invaluable tool for making your house comfortable again. We hope we helped you answer the dehumidifier vs open window debate!
Last update on 2025-01-22 / Affiliate links / Images from Amazon Product Advertising API
