Dehumidifiers are a useful appliance for any home as they help to both prevent mold and keep your home more comfortable by removing excess moisture from the air.
However, running a dehumidifier for long periods of time can use a lot of energy, and the air in a home can also be too dry as well as too humid in terms of a healthy and comfortable living environment.
A dehumidifier should be turned off when the desired humidity for your home has been reached, commonly within the range of 30 to 60%. Dehumidifiers typically offer the ability to set the desired humidity level where the dehumidifier will automatically turn off when reached.
If you want to get the most out of your dehumidifier and ensure that your home stays comfortable, knowing when to turn your dehumidifier off can be just as important as knowing when to use it.
We turn our dehumidifier off before going to sleep, if our target humidity level of 50% hasn’t already been reached by the time we do so.
Keep reading to learn when and why you should turn off your dehumidifier.
When Should You Stop Running A Dehumidifier?
A dehumidifier is an appliance that should ideally be kept running until it’s done and for best performance is something that shouldn’t be turned on and off regularly.
Doing so can make it extremely difficult for the dehumidifier to do its job properly, and if you have a whole-home dehumidifier turning it off and on can be quite a hassle.
That being said, there are times when you should put your dehumidifier into hibernation mode for a while.
Two main factors determine when your dehumidifier needs a break: temperature and relative humidity.
Temperature
Cold air holds less water vapor than warm air, meaning that the relative humidity in your area and your home will naturally drop in the winter months.
When the weather turns colder, your dehumidifier may not be as necessary.
As there’s naturally less humidity in the air you may not need the dehumidifier to take the mugginess out of the it.
When the temperature drops to around 65 or 60 degrees Fahrenheit, then it may be time for some users of refrigerant dehumidifiers to store them away until warmer weather arrives once again.
Relative Humidity
The other factor that can determine when you should turn your dehumidifier off is relative humidity.
There are two terms you need to know to understand humidity levels in your home.
- Absolute Humidity: Absolute humidity is the amount of moisture in the air. It’s calculated using the mass of water vapor per the mass of air.
- Relative Humidity: This is a percentage expressing how much absolute humidity (mass of water vapor) there is in the air compared to how much water vapor the air can hold at that temperature.
When relative humidity is at 50%, it means that the air has half as much moisture as it can at the current temperature.
When relative humidity reaches 100 percent, the air cannot hold any more water vapor, and it rains.
Winter air with 50 percent relative humidity will feel a lot different than summer air with 50 percent relative humidity because the cold air has a much smaller maximum moisture level.
You typically use relative humidity over absolute humidity because it tells you more about how the air feels.
Knowing that there is one gram of water vapor per cubic foot of air tells most people very little, but knowing that the relative humidity is 75 percent tells you that the air is quite saturated with moisture. You know that it will feel humid.
There’s moisture in the air all the time, so relative humidity has to get quite high before you start to notice it.
Relative humidity needs to get over 50 percent before it starts to feel moist.
Relative Humidity And Your Dehumidifier
What does all this relative humidity mean for your dehumidifier?
The relative humidity is an excellent way to judge the effectiveness of your dehumidifier to determine when it is time to turn it off.
In general, when the relative humidity drops below 30 percent (at the very minimum) then your dehumidifier can take a break.
The relative humidity is therfore a clear way to establish when to turn your dehumidifier off, but how do you know what the relative humidity in your home is? Luckily there is a tool that makes it quite easy: the humidistat (also known as the hydrometer).
A humidistat looks like a digital thermometer. You can buy one for less than 20 dollars, and you will always have a clear visual display of the relative humidity in your home.
Many dehumidifiers even have a humidistat built-in, so you may want to check yours out before buying one.
Why Should I Turn Off My Dehumidifier?
Dehumidifiers can help to prevent mold and make the air in your home more comfortable.
Running your dehumidifier all the time can also lead to other issues at low humidity.
Here are some of the top reasons that you need to turn your dehumidifier off when the temperature and/or relative humidity drops.
Preventing Damage To Your Dehumidifier
Without getting into too many technical details, dehumidifiers work by cooling and then reheating air to gather the water vapor.
If the temperature is already low when your dehumidifier cools air to create condensation, then that condensation may freeze on the dehumidifier’s coils. This can damage your device, shortening its lifespan and even breaking it altogether.
It’s therefore essential that you do not run a dehumidifier in a space that’s less than the temperature of what the manufacturer recommends.
If you’re worried about the possibility of a damp basement in the winter months, a space heater can be a better choice to combat the issue.
Saving Money
Dehumidifiers use power, and power costs money.
Running your dehumidifier 24 hours a day all year long can add significantly to your overall electricity costs.
Once the temperature and relative humidity drop below a certain point, then the dehumidifier is not doing you much good, and is also costing you.
Your Comfort And Health
We all know that too much humidity can make you extremely uncomfortable but too little humidity can do the same thing in different ways.
Remember that relative humidity has to be well over 50 percent before it gets noticeably muggy, so people are used to living in air with a fair amount of moisture.
Keeping your home’s relative humidity below 30 percent consistently can result in some nasty effects such as:
- Dry and itchy eyes
- Increased growth of some types of dust mites and bacteria
- Cracked skin
- Sore throat
If you keep your dehumidifier running all the time, you may make yourself uncomfortable and create possible health risks.
You should turn your dehumidifier off when it’s appropriate.
Do Dehumidifiers Automatically Shut Off?
If you’re the type of person that tends to forget about their dehumidifier, you will be happy to learn that many dehumidifiers have solved the problem of knowing when to cut them off for you.
Dehumidifiers with a built-in humidistat can monitor the relative humidity and automatically turn off when it hits a certain point, which you set.
For dehumidifiers with an automatic shut-off, any relative humidity setting between 30 percent and 50 percent is a healthy shut-off point.
Still, even with automatic shut-off, you may want to unplug your dehumidifier in winter to avoid the possibility of damage.
Also, remember that any device that uses such self-regulating systems still needs to be manually checked. If something goes wrong with the monitoring system the dehumidifier will run continuously.
Conclusion
A dehumidifier should be turned off when either the target humidity for the air in your home has been reached, or when it becomes too cold for the dehumidifier to operate safely.
Many dehumidifiers automatically shut off when a target humidity has been reached meaning that you won’t manually need to turn it off.
It’s recommended that the humidity of a home is kept anywhere from between 30% and 60%.
Further Reading
Does A Dehumidifier Need To Be On All The Time?