Is It Safe To Leave Humidifier On When Not Home?

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Do you ever wonder if it is safe to leave the humidifier on when away from home? You’re not alone. As someone who often goes out, I want to ensure the air is humid and comfortable enough once I return, especially during winter.

The answer largely depends on the type of humidifier you have. It is safe to leave a whole-house humidifier unattended for long periods. However, the same could not be said for a portable humidifier because it occasionally requires a water refill.

This article will cover the other factors to consider before leaving the humidifier on when not home. I’ll also teach you the benefits and downsides of using humidifiers for long periods.

Is It Safe To Leave Humidifier On When Not Home?

Humidifiers are usually safe to run for many hours, but here are a few things to keep in mind.

It is generally safe to run a humidifier unattended as long as it’s hooked up to a consistent water supply. 

Otherwise, I don’t recommend leaving the unit switched on for more than 24 hours if it needs constant water refill.

Below are some considerations before you leave the humidifier running all night when heading out for work or a long vacation.

Type of Humidifier

Type of Humidifier

The first thing to consider is the type of humidifier you own.

If you have a whole-house humidifier, it is likely attached to a water supply. That connection allows you to run a humidifier without interruption. As such, you can safely leave it on when you’re away from home.

But what if you own a portable humidifier that is not connected directly to a water tank or other water supply? Well, you can still leave it on, but make sure you refill it with water. 

Most units require replenishment every day or so (i.e. around 24 hours of run time). Meanwhile, some smaller devices need a refill two or three times daily. So, it might be impossible to leave a humidifier running for more than 24 hours without stopping to refill.


You must also think about how long you’ll be out of town or away from home before you leave a humidifier running.

Planning on returning within the day after work or errands? Then, it is safe to use both whole-house and portable humidifiers.

If you’ll go on a week-long vacation, you can leave the whole-house humidifier on without facing serious problems. Using this device unattended for a month is also fine, as long as you’re prepared to face one major consequence—higher electricity bills.

However, if you’re still not sure about when you’ll return and you use a portable humidifier, it is best to turn it off for your safety. The last thing you want is to find an overheated device.

Existing Conditions

Another thing you shouldn’t overlook is the existing humidity level in your home. It can help you decide whether to leave a humidifier running or not.

For example, if the relative humidity indoors is below 30%, you can safely leave the humidifier on when you’re not home. Doing so helps you maintain the recommended humidity levels and reduce the harmful effects of dry air.

Those living in places with a relative humidity between 40% and 60% don’t necessarily need to use a humidifier. If the moisture level is on the lower side, it’s acceptable to run the device for a few hours. However, avoid leaving it on for too long because it can lead to excess moisture in the air. 

Finally, if you reside somewhere with a humid climate, you shouldn’t use a humidifier at all. Leaving this device on when the relative humidity levels are already high can lead to several problems. These include mold growth, wood damage, and unpleasant smells, among others. Consider using a dehumidifier instead, which removes excess water in the air.


The last factor to consider is the settings on your humidifier. It can help you regulate humidity levels in your home safely while you’re away.

I always recommend using a humidifier with low settings. A low humidity function can increase relative indoor humidity to a comfortable level. At the same time, it prevents saturating the air with too much moisture.

What Are the Benefits of Leaving Your Humidifier On When Not Home?

What Are the Benefits of Leaving Your Humidifier On When Not Home

Leaving the humidifier on while away from home has several benefits.

First, it maintains a consistent level of humidity in the air even when you’re not home. It can help prevent nasal congestion, throat irritation, dry skin, and cold symptoms.

Having the humidifier switched on can also eliminate bacteria and other allergens in your room. These contaminants thrive in dry environments. By introducing necessary moisture in the air, the humidifier stops them even before they grow.

Plus, the humidifier protects wooden furniture, plants, and paint from drying or cracking. It can prolong their lifespan, so you can enjoy a beautiful home for many years to come. 

What Are the Risks of Keeping A Humidifier On When Not Home?

What Are the Risks of Keeping A Humidifier On When Not Home

However, leaving a humidifier operating when not at home comes with consequences.

The most common issue is the risk of mold and mildew in your room. Since the humidifier introduces moisture in the indoor air, it can promote fungi growth on wooden furniture. To prevent this, clean the device regularly. You must also set the correct humidity level.

Another downside is the increase in electricity costs. If you want to run the humidifier when you’re away from home, prepare to spend a lot of money on electric bills.

Finally, continuous humidifier use can lead to potential damage, especially if it’s not properly maintained. Give time for the device to rest. Also, make sure you refill the water container and clean the filters.

How Long Should You Run a Humidifier in a Bedroom?

How Long Should You Run a Humidifier in a Bedroom

The exact duration to operate a humidifier in a bedroom depends on several factors. These include the existing humidity level, room size, and personal preferences.

If your bedroom has humidity in the typical recommended range (30 to 50% relative humidity), using a humidifier for up to four hours is best.

If the level falls below the recommended relative humidity, you can leave the humidifier at night. You can also operate the device longer if the room is larger or if you’re extra sensitive to allergens.

Rooms that have too much humidity, such as basements and bathrooms, must avoid humidifiers altogether. Instead, use a dehumidifier to reduce over humidification. 


A humidifier is a device that can maintain optimal humidity levels inside your home. However, if you plan to be away at work or on vacation, you may wonder whether it’s safe to leave it on when not at home.

The answer is complicated, as it depends on several factors. These include the type of humidifier you own, the current humidity levels, the exact duration you intend to run the device, and the settings you use. In general, it is safe to leave a whole-house humidifier on for long periods during dry winter months. But it’s not recommended to use a portable model unattended because of its unique needs.

Did you find this article informative? Visit our blog page to read more information about humidifiers and home maintenance.

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