Dehumidifiers are great for managing indoor humidity levels to protect your home and belongings.
However, many people are left wondering when to use dehumidifier units for the best results.
Well, the simple answer is that you should use it whenever it gets too humid.
So when is that, and how can you tell?
In this guide, I’ll explain when it’s best to use your dehumidifier, the benefits of using it at different times, and the signs to look out for that you need dehumidification in your home.
Dehumidifiers are designed to remove excess moisture from the air, and the best time to use a dehumidifier is when the relative humidity in your home gets too high.
The Environmental Protection Agency recommends keeping the humidity levels in your home are 30-50%, so if the relative humidity rises above 50%, it’s time to use your dehumidifier.
There are certain advantages to using the appliance at specific times of year or day. Still, ultimately, if you have more moisture in the air than you want, then it’s the right time to use your dehumidifier.
If you notice any of the following, then it’s a sign that there is too much humidity in your home:
- Sticky and stuffy conditions
- Noticeable condensation on interior glass, windows, and mirrors
- Increased mold, mildew, and bacteria growth
- Musty odors
- Allergy symptoms worsening
- Water marks
- Peeling wallpaper and paint
It’s usually best to use a dehumidifier in the summer months when humidity levels rise.
This does vary depending on where you live, and some locations will have humid conditions year-round, but even places with colder climates tend to have more humidity in summer.
The warm conditions can lead to humidity in your home, reducing indoor air quality.
Removing moisture can reduce excessive humidity, make you feel more comfortable, and protect your belongings.
Dehumidifiers can be used at any time of day to regulate the humidity level, but you can lower your energy costs by using them at night.
If you have a time-based electricity rate rather than a fixed tariff, you can run your dehumidifier between 10 pm and 7 am and pay less for the energy.
Remember, your dehumidifier is there to stop a room from having too much moisture, so it isn’t always practical to only use them at night.
If you have severe moisture issues, you may need to use it during the day or even 24/7, so it’s worth considering the energy efficiency of your chosen model.
Your dehumidifier should be placed as close to the source of moisture as possible.
This will allow it to regulate moisture levels in the room most efficiently.
This is usually basements, bathrooms, crawlspaces, or laundry rooms, but it’s not necessarily the same in every home.
Warm air rises, so it’s best to place the appliance in a raised area.
Placing the appliance on a stable table, shelf, or at the top of your basement stairs can prevent humidity build-up and help protect your family’s health and belongings.
Remember, choosing the right size dehumidifier is as important as where you place it.
If you have several large rooms with high humidity, it may be worth considering whole-home dehumidifiers.
A dehumidifier removes moisture from the air and lowers the humidity in an area. There are several different types, but they all essentially operate in the same way.
Humid air is drawn in, the moisture is removed, and dry air is blown out on the other side.
Refrigerant dehumidifiers are the most common, and they provide dehumidification by cooling and heating the air.
Desiccant versions are also fairly common and work by passing moist air over an absorbent material to remove the moisture.
They work well in a cold basement or cellar because they won’t freeze over.
Additionally, your indoor air is pulled through filters, and the dehumidification process will help to remove some impurities, leaving you with healthier air.
Many people associate Summer with a dry environment, but it’s actually when humidity levels rise the most and when your dehumidifier can become the most useful.
Here’s why you should be using dehumidifiers most when it gets hotter:
Humid air can cause a number of health issues.
Damp air can make it harder to breathe, especially for those with asthma, plus there are a greater number of dust mites that breed quickly in these conditions.
Mold issues can also be hazardous, especially black mold spots that can start appearing on your walls and ceilings.
This can lead to mold spores being released into your home, negatively impacting your indoor air quality and causing respiratory infections. 
Using a dehumidifier or HVAC system will reduce the humidity, prevent mold growth, and kill dust mites. This will leave you with a healthier home.
Damp conditions can lead to mold growth and attract pests into your home.
This can include termites which can eat away at your home’s foundation and cause a lot of expensive damage.
Plus, the damp conditions can damage furniture, books, and electronics.
In extreme circumstances, it can even damage your electronics which can be dangerous to you and your family.
By running a dehumidifier, you can keep your humidity at an optimal level to protect your home and belongings.
In the hottest months, the temperatures can become unbearable in your house.
A dehumidifier doesn’t actually lower the temperature in the room, but it can make your home feel cooler by removing a lot of the moisture and allowing your body to sweat properly.
It’s no replacement for an air conditioning unit, but at certain times of year, it can have a positive effect on your body and make you feel a lot cooler.
Dry air makes you more comfortable, and because a dehumidifier can keep your home dry, it can actually stop you from needing to use an air conditioner.
Dehumidifiers use much less energy than an air conditioning device, so you can run them longer without spending as much.
If you have the right model and run it regularly, you can keep the humidity at the ideal level to feel cool and reduce your energy bills.
Choosing The Right Size
The size of your dehumidifier is not the physical dimensions; it’s how much water it can draw from the air.
This is usually measured as pints or liters per hour. Your average household model will have a capacity of around 30-50 liters, but you can get much larger units.
Larger spaces and very humid conditions will need a larger dehumidifier.
As a first step, it’s important to measure the space and determine the right dehumidifier to give you the performance you need.
Choosing The Right Type
There are two main types of dehumidifier; portable and whole-home units.
Whole-home units are useful for those who live in a hot climate and regularly need dehumidification across their whole home.
Portable dehumidifiers are useful for specific rooms or for those who only need dehumidification at certain times of the year.
The purpose of dehumidifier units is to remove moisture, and modern models have a lot of great features to aid their performance and make them easier to use.
These features include automated controls, built-in humidistats to continuously measure moisture levels, and laundry modes for intense drying.
Think about how and where you’re planning to use the appliance, and look at what you need a dehumidifier for so you can find features that will boost the performance.
Can you use a dehumidifier during winter?
Yes, you can run a dehumidifier in winter, but the refrigerant in the cooling coils can freeze in temperatures below 60 degrees Fahrenheit, so you may need to avoid very cold basements or cellars.
How often should you use a dehumidifier?
You should use your dehumidifier for as long as it takes to reduce the humidity to the right level. This could mean a few hours a day, or it could mean you have to run it constantly. Just ensure you’re emptying the tank frequently and that it isn’t removing too much moisture.
When should you not use a dehumidifier?
You shouldn’t use a dehumidifier if the relative humidity is less than 30%. You should also avoid running them when the heat falls below 60 degrees, or they could freeze and break.
What’s the difference between a humidifier and a dehumidifier?
A humidifier adds moisture to the air and raises relative humidity. A dehumidifier removes moisture and lowers the relative humidity. Generally, humidifiers are useful in dry climates, whereas dehumidifiers are useful in hot, wet climates.
Generally, you should use your dehumidifier as and when the humidity levels get above 50%, and for most people, that’s in the hot summer months.
However, it can vary depending on where you live, so it’s worth investing in a humidistat to check.
Hopefully this article has helped explain when it’s best to use a dehumidifier so you can get the most from your appliance.