Can You Leave An Air Purifier On All Night

Air purifiers have become a household item in the past few years and rightly so as the average contaminant levels in the indoor air have quadrupled in the same time. Many people are confused if they can run air purifiers throughout the day?

The simple answer is yes, there are some excellent air purifiers out there that feature auto mode and multiple air quality sensors, which allow them to detect changes in the air quality and take appropriate action accordingly.

While this might be enough for certain areas, if your area is affected badly by wildfires or odors and you’re wondering if you can run air purifier at night or more importantly can you keep an air purifier on all night then you’re in the right place.

Air purifiers with an all-night mode are meant to be used all day and into the night as well. These purifiers have been certified to be safe for use around the clock and also feature some nifty features like lights out mode and night-friendly air purifier features like silent airflow.

If you’re not sure if your air purifier is safe for night time use we’ll add some pointers that will help you decide.

Is it OK to Leave Air Purifier On All Night?

Yes, you can leave an air purifier on all night. Like air conditioners and refrigerators that are designed to run all the time, air purifiers also feature a similar design. Running an air purifier all night does not pose any safety hazard. On the other hand, it can actually help you sleep better.

When air pollution is at its peak outside, indoor ventilation can be maintained by using an air purifier for a few hours. Typically a 2-3 hour cycle will suffice in a simple room with average contaminant levels. Our guide perfectly explains how long you need to run your air purifier during the day.

If you’re planning to run air purifier at night, here are some of the advantages this practice will bring and a few drawbacks that are applicable in certain scenarios only.

Advantages of Leaving Air Purifier On All Night

  • If you have a pet around and are fed up with the odors then running an air purifier can actually help keep the odors at bay. The activated carbon filter in the air purifier helps solve the odor and dangerous chemical problems.
  • Sensitive groups can enjoy the feel of stress-free breathing thanks to the removal of PM2.5 particles and microbes that can cause the respiratory airways to become inflamed and clogged.
  • If there is active construction work going on close to your home chances are PM2.5 is the least of your concerns. VOCs and other problems like unwanted radon can actually affect your life expectancy. Thankfully some excellent air purifiers can handle these issues effortlessly.
  • You wouldn’t believe it, but if you run a nail salon or someplace where the chemical concentration is higher than usual, using an air purifier can keep your health in good condition while also keeping the appliances in the space safe.
  • Your air purifier can help your toddler or yourself sleep better thanks to the continuous white noise (constant hum) that some air purifiers produce.

Disadvantages of Running an Air Purifier at Night

  • Perhaps the only disadvantage of running an air purifier at night is the increased operating cost as longer runtimes mean more frequent filter changes.
  • The larger air purifiers are rated at 90W or some even above that; meaning you might experience a slightly higher electricity bill, but if you’re prone to allergies or have any condition like asthma, the higher charge is definitely worth it.
  • Ozone-based air purifiers release traces of ozone into the indoor space. Ozone is a known lung irritant and can cause allergy flareups and can trigger breathing problems.

All Night Mode Air Purifiers – Should Air Purifier Run All Day or Night?

Yes, all-night mode air purifiers are the perfect appliances if you’re looking to run air purifier all the time. Why? Night-friendly air purifiers feature a night mode that turns off the lights and makes the noisy machine into a silent night air purifier.

Air purifiers use a thick HEPA filter that can force the fan into working hard and hence produce a low vibratory hum. True All-night mode air purifiers use innovative ways of getting around this problem by using technologies like HEPASilent.

If you’re looking for a good HEPASilent air purifier, this guide compares Blueair 121 Vs 211+, two of the best HEPASilent air purifiers out there.

To be a silent night air purifier, the purifiers switch to the lowest fan speed hence reducing the power draw. This also reduces the noise coming out of the appliance. The silent night air purifiers are also pet friendly so whether you’re using the purifier for cat litter or a purifier for ferret odors then all night mode air purifiers are the best thing for you.

3 Best Air Purifiers For Sleeping

We have done thorough research by going through 450+ air purifiers and found only a few competitive enough to be used in the bedroom. Let’s dive into the list to find the best solution for you.

Filtration Stages: 3
CADR: 245 cfm
Coverage: 800 sq. ft.
Dimensions: 15 x 8.5 x 25 inches
Filtration Stages: 3
CADR: 350 cfm
Coverage: 540 sq. ft.
Dimensions: 20 x 13 x 13 inches
Filtration Stages: 4
CADR: 268 cfm
Coverage: 350 sq. ft.
Dimensions LxWxH: 9.6 x 16.8 x 18.3 inches

1. Alen BreatheSmart 45i Air Purifier

Alen BreatheSmart 45i

Out of many air purifiers, Alen models are able to get certified and approved by SleepScore, including Alen BreatheSmart 45i, for a swift and magical sleep.

Alen BreatheSmart 45i is the first air purifier validated and approved by SleepScore Labs to get a peaceful sleep. On all fan speeds, even the highest setting, it produces “pink noise” giving away a calming and tranquilizing effect.

The unit intends to create a more breathable environment where air pollution is common and help people with allergies by filtering out dust and particles as small as 0.3 microns.

The air purifier uses a true HEPA filter and circulates clean air in a room of 800 sq ft every 30 minutes. Even though Alen can work with windows open, it would not be much efficacious in filtering harmful particles as with them sealed.

Not it is just energy certified but has LED light coded with 5 colors for different indications. Its laser smart sensor detects all the possible harmful contaminants and adjusts the settings according to it.


  • The auto smart sensor adjusts the purifier as per the surroundings
  • Offers lifetime warranty
  • Soothing pink noise in all fan settings for a better sleep quality


  • A bit bulky to carry around

[su_button url=”” target=”blank” style=”flat” background=”#2096f3″ size=”8″ center=”yes” radius=”5″ icon=”icon: amazon” text_shadow=”none” rel=”nofollow”]Check Price on Amazon[/su_button]

2. Blueair 211+ Air Purifier

Blueair 211+

Equipped with both mechanical and electrostatic filtration stages, Blueair 211+ is just right for a mere price of $300.

This air purifier uses advanced Hepa filter technology that ensures filtering out any particulate matter brought by outdoor air, including pet dander, feathers, smoke, dust, and other pollutants to give off a constant flow of clean, breathable, and fresh air in the room at night.

With a CADR of 340cfm, it can easily cover your bedroom space of up to 540 sq ft and help you wake up every morning without any allergy or flu. The 3 replaceable filters can hold you up for 6 months ensuring the cleanest air throughout the period.

It has three adjustable fan speeds and the lowest airflow speed of 31 dB(A) with a dim white light is nothing but best to fall asleep peacefully after a hectic day.

Coupled with its HEPA silent technology, this unit stays impeccably quiet at its lowest fan speed and, remains the best choice for many till now.


  • Compact and easily movable
  • Gives sound equal to of whisper at the lowest fan speed setting
  • Premium Swedish design suitable for a modern look


  • Not equipped with smart features

[su_button url=”” target=”blank” style=”flat” background=”#2096f3″ size=”8″ center=”yes” radius=”5″ icon=”icon: amazon” text_shadow=”none” rel=”nofollow”]Check Price on Amazon[/su_button]

3. Coway Airmega AP-1512HH Air Purifier

Coway Airmega AP-1512HH

Coway might be the name many have not heard of, but it has a few exceptional models, like Coway Airmega AP-1512HH, which are specially made for bedtime to get a sound sleep.

This compact and well-built HEPA air purifier comes with 4 filtration stages and an indoor air quality meter at a much more affordable price than competitors, making it one of the most reliable options out there.

The automatic mode makes sure to adjust the settings and fan speed to keep the room air quality fresh and up to the mark. Unlike most air purifiers, by keeping LED lights and timers, Coway knows exactly how to rule out other options for the buyer.

Coway Airmega has made our list because when on its lowest fan speed, it makes barely any audible noise bringing the whole deal to another level.


  • Senses clean air and turn off automatically after half an hour
  • The silent operation helps get a sound sleep
  • A bipolar ionizer assures streams of clean air


  • No child lock feature

[su_button url=”” target=”blank” style=”flat” background=”#2096f3″ size=”8″ center=”yes” radius=”5″ icon=”icon: amazon” text_shadow=”none” rel=”nofollow”]Check Price on Amazon[/su_button]


If you’re looking to run your air purifier all night and can’t find a dedicated night mode on it, you can simply turn your air purifier to the lowest fan setting.

Tired of the humming sound coming from your air purifier? Some people think that covering the air inlets reduces the noise but that would be far from the truth.

While the practice might reduce the noise in certain cases you might be causing irreparable damage to the air purifier. Opting for an air purifier with a dedicated night mode would be the more prudent choice.

In addition, regularly maintaining the air purifier filters can go a long way in ensuring safe, breathable air, and also ensure that your air purifier lasts a long time.