The Best Time Of Day To Use A Dehumidifier

Dehumidifiers help to remove excess moisture from the air in a home but this process can’t be undertaken quickly.

A dehumidifier will need to run for several hours before a noticeable decline in indoor humidity can be seen, and this energy usage can add up over time.

The most optimal time of the day to use a dehumidifier is during the nighttime, typically between the hours of 10pm and 7am. Relative humidity levels are highest at night and decrease from late morning to mid-afternoon, and using overnight can save on electricity costs.

When the air is humid we’ll typically run our dehumidifier overnight but when we have washing to help dry we’ll often leave our dehumidifier during the day, even if it costs us more to do so.

Running our dehumidifier at night

If you live in a humid climate, you’ll want to know more about how to use a dehumidifier to optimize comfort.

Read on to learn more about the best time of day to use a dehumidifier.

Use A Dehumidifier At Night

Humidity levels are generally highest at night and lowest in the afternoon.

Using a dehumidifier at night is therefore one straightforward way to address the rise in humidity that occurs while you sleep. You may also notice a clear difference when you wake up feeling more refreshed.

Along with the time of day, consider the following factors when using a dehumidifier:

  • Appliance location
  • Humidity level preferences
  • Seasonal climate
  • Maintenance

A common suggestion is to use a dehumidifier 12 hours a day.

You can leave the appliance on for 12 consecutive hours or break it up into shorter segments, depending on your schedule and daily routine.

For example, it does not make much sense to operate your dehumidifier while your house is empty during the day.

Turning it on only when your home will result in a more comfortable atmosphere while you are home to enjoy it while leading to lower energy consumption by turning it off when you are away.

Location Matters

Placing your dehumidifier in the wrong location can mean that your dehumidifier needs to run for longer.

By optimizing location, you can make it easier to run it overnight and leave it off during the day.

The best location for your dehumidifier depends on the size of the room and source of humidity.

For larger spaces, use a dehumidifier with more capacity for the water. They function best when they are placed at least six inches away from walls or large furniture, so be sure to clear the area of any surrounding objects.

The manual to our own dehumidifier explains:

For maximum performance the unit should be operated at least 20cm away from walls and 50cm from other objects within the room. A badly positioned dehumidifier will have little effect.

Somewhere central is a good location for a dehumidifier

If possible, determine the source of humidity in your living space.

Check for leaks in the kitchen or bathroom that may be contributing to the dampness. A window might be letting moisture in from outside.

Is the basement or laundry room typically more humid than the rest of your house? If so, you found the perfect spot for your dehumidifier. Placing it there will help keep humidity levels lower in the rest of the house. 

Set Relative Humidity Level Between 40 and 50%

Setting the proper humidity level on your dehumidifier can help it run more efficiently, which makes it easier to only run it for a portion of the day.

Relative humidity (RH) is a percentage of the maximum moisture that can be retained at a certain temperature. For example, if RH is 100 percent at room temperature, a rise in humidity will lead to visible water vapor or precipitation.

RH peaks in the early morning, at about 6 am, before decreasing and reaching a minimum at about 4 pm. This is why dew drops form by the early morning hours.

This also explains why running a dehumidifier overnight is typically the best time of day to operate this appliance.

With rising humidity overnight, the dehumidifier can work against that so that your humidity is already low by the time the sun comes up and starts burning away moisture.

At that point, the sun itself can take over the job of your dehumidifier.

Using our dehumidifier to keep humidity levels lower overnight

According to a study on indirect health effects of relative humidity indoors, the survival of airborne bacteria and viruses is minimized at a relative humidity between 40 and 70 percent.

Mites and fungi are minimized at a relative humidity under 50 percent. In other words, set your preferred humidity level between 40 and 50 percent to help eliminate airborne allergens and infectious agents from your home.

Consider Seasonality

Humidity is typically highest during the summer and lowest in the winter.

You will probably want to use a dehumidifier most during the summer season. However, this assumes that there are no leaks letting moisture indoors during the rainy season.

If you live in a particularly damp climate, you may need to run your dehumidifier for a bit longer than 12 hours during the summer.

This can mean switching it on once or twice during the day in addition to running it overnight.

When winter comes around, you can scale back again to using it only at night with the same effect.

If the air is too dry in the winter, consider switching to a humidifier to alleviate any discomfort. This may help relieve cold and flu symptoms.

As we live in a colder climate, we still use our dehumidifier throughout winter to help with window condensation and the buildup of mold.

Window Condensation
Depending on where you live, a dehumidifier can be very useful in every season

Regular Maintenance For Dehumidifiers

Finally, be sure to clean and maintain your dehumidifier appropriately to maximize efficiency.

Same as with the above steps, this also helps to ensure that sporadic or overnight usage will be enough to maintain lower humidity levels. This is especially important during the summer or whenever you are using the dehumidifier on a daily basis.

Remember to do the following to get the most out of your dehumidifier:

  • Dump out wastewater regularly. Bacteria and mold may grow if left sitting for a long time. If you do not dump wastewater, the dehumidifier will switch itself off, which means that you will need to turn on your dehumidifier during the day.
Dehumidifier Drain Channel
Mold growing on water tank inlet on our dehumidifier
  • Vacuum coils when they have excessive dust buildup. If you live in a colder climate, unplug the appliance and check for frost buildup.
  • Change the filter when necessary. You should change the filter at least two times a year. Reference your owner’s manual if you are unsure about how often the filter needs to be changed.
Not changing or cleaning the filters regularly can lead to a less efficient dehumidifier

Proper use and care of your appliances will benefit your health and finances in the long run. Instead of replacing pricey objects, you can maintain them as necessary.

By maintaining your humidifier, you may also find that you do not need to run it for the full 12 hours per day to maintain your comfort.

Use A Dehumidifier Strategically

If you’re unable to leave the dehumidifier on overnight, consider using it at specific times throughout the day.

  • While a new paint job is drying
  • During and directly after mopping or shampooing carpets and furniture
  • While running your clothes dryer
  • When someone in your home is showering or bathing
  • While you are cooking or baking
  • When you are cleaning your home or doing dishes
Dehumidifier Drying Washing
A dehumidifier can be used during the daytime to help get rid of excess moisture brought indoors by laundry

Any of these situations would be a good reason to run your dehumidifier, as they all include activities that introduce moisture into your environment.

Running a dehumidifier at the same time will reduce the humidity levels in your home at the same time.

What Is The Best Time Of Day To Use A Dehumidifier?

The best time to use a dehumidifier is generally at night or during activities that produce moisture.

Turn it on before bed and turn it off in the morning, after about 12 hours.

Remember to consider the humidity source and seasonal climate before setting it up.

If you prefer to use it in the daytime, turn on the dehumidifier when you are using water or drying laundry, carpet, or paint indoors. There is no rule set in stone for when to use the appliance, so choose the best strategy for your lifestyle.

Further Reading

What Should I Set My Dehumidifier At?

When Should I Turn Off My Dehumidifier?

What Are The Settings On A Dehumidifier?