March 12, 2021

Can You Use A Diffuser & An Air Purifier At The Same Time?

Is This the Right Way to Make the Most of These Devices?

Picture this: you’re lying on your sofa with a good book or simply relaxing with your eyes closed, your living room is bright and airy, and it feels clean and smells wonderful - maybe you even doze off. Sounds great, right? Is this achievable by using an air purifier and diffuser at the same time?

Whether you own one and want to invest in the other, have neither and want to buy both, or have both already and simply want to find out how to utilise them to their fullest effect, you’ve come to the right place! This article will look at what each of these items does and why they’re loved by so many.

To give you a quick answer, you should be able to use both devices at the same time, however it’s not as simple as a straight black-and-white answer. Combining both an air purifier and a diffuser won’t always be the best option, but you’ll see more on that later!

We’ll also be discussing the best ways to get the most out of them whilst using them in the same house, so that you don’t waste your time or money. Keep reading to learn more and by the time you finish, you’ll know exactly how to get clean, fresh, delicately scented air that will help you to feel calm and relaxed!

If you have any questions about what these devices are or how they work, the first few sections of this post should lead you to all the answers you need.

What is an Air Purifier and How Does it Work?

In brief terms, an air purifier is a device designed to clean the air in a space by filtering out dust, allergens, and other particulate matter. Once impurities have been removed, the cleaned air is then output back into the room.

The name “air purifier” can be slightly misleading as no air purifier will leave you with air that’s 100% pure, but they do work to remove a good proportion of allergens, dander, and toxins depending on the make and model you go for.

Air purifiers come in several different categories which each have their own advantages and drawbacks, which you can learn more about here.

What is a Diffuser and How Does it Work?

As the name suggests, diffusers…diffuse. You can get diffusers that diffuse different kinds of substances, but the most common types are essential oils, fragrances, and aromatherapy oils. Diffusers work by releasing said substance into the air in a room, in a fine mist or spray that then diffuses through the air to fill the space.

Most people use diffusers in their homes to spread pleasant fragrances across rooms in order to create a particular ambience or to enhance the clean and relaxing atmosphere of their house. There are several kinds of diffuser available on the market which we’ll now go into briefly:

Heat Diffusers

Heat diffusers are probably the cheapest and most commonly overlooked type of diffuser out there. The premise is simple: a candle, tea light, or bulb is used to heat a scented oil (usually aromatherapy or essential), causing the oil to disperse into the air, carrying and spreading the scent.

Because heat diffusers are silent, they are commonly used in spas and other settings where quiet and relaxation are key.

Ultrasonic Diffusers

This might sound quite high-tech, but the mechanism is actually quite simple. A small plate vibrates rapidly inside the body of the diffuser in a chamber of water-diluted oil. The vibrations cause the water and oil molecules to break down into smaller components which are then sent into the air to be diffused.

The spread of scent will be determined by the air currents in the room so ultrasonic diffusers are not generally used  in very large spaces as the scent would likely be unable to reach all areas.

Nebulizing Diffusers

These kinds of diffusers utilise a constantly flowing jet of air to diffuse scent across a space. This jet of air is passed through a tube containing the essential oil and the resulting air stream causes a vacuum effect that draws the oil out of the tube and into the open air in a fine mist.

Because the oil used in a nebulising diffuser is not diluted or broken down, the intensity of scent carried through the space tends to be better than other types of diffuser.

Evaporative Diffusers

You might already be able to tell that these diffusers work using evaporation as a mechanism for dispersing scent. A filter is dripped with scented oil before a small internal fan blows through the filter, causing the oil to evaporate into the air faster than it would without the fan as a catalyst.

Because the lighter components of the oil evaporate and diffuse more quickly and the heavier components take longer, evaporative diffusers are not the best method for getting a fully balanced diffusion.

Back to the Question at Hand

Now that we know a bit about the different types of air purifiers and diffusers, and how they work, we can start unpacking the answer to the question of whether you can use both devices at the same time.

The answer to this question is not clean-cut. There are several considerations to make that will create different results so before deciding the best course of action for your home, take a look at these factors:

Type of Air Purifier Filter

Depending on what type of filtration system your air purifier uses, having your air purifier and diffuser running in the same room concurrently might not be as effective as you hope.

For example, air purifiers that use a carbon filter are designed to absorb odours. Due to the simplicity of carbon filters, they are not always able to distinguish between unpleasant odours and pleasant fragrances, meaning the scent spread by your diffuser might be lessened or negated as the fragrance-containing particles are neutralised by the air purifier.

If you have a HEPA filtered air purifier or an ionic one, this won’t be an issue as neither of these air purifiers is designed to target odours. This means if you have one of these types, you’ll be fine to run it alongside your diffuser.


This will depend again on the types and models of air purifier and diffuser you’re using. Some air purifiers are much louder than others, and the volume will also be affected by how hard the air purifier is having to work.  

A HEPA air purifier is much louder than an ionic air purifier, and air purifiers that are larger or cheaper will generally be louder than smaller, more expensive ones.

Of all the types of diffuser, the noisiest are probably the evaporative and ultrasonic, even though they make different kinds of sound (fan noise and running water noise respectively).

If you had one of these diffuser types running alongside a HEPA air purifier, although the noise level wouldn’t be extreme or even unpleasant necessarily, it would create a hum that might be distracting or inappropriate depending on which room they were in – you don’t want the noise keeping you awake or disrupting your work.

Running Costs

Because most air purifiers and diffusers rely on electricity to function (with the exception of a heat diffuser), running both devices constantly can be a good way to rack up a hefty electricity bill! If you’re concerned about keeping running costs to a minimum, it’s probably a good idea to run each device at a different time of the day rather than simultaneously.

Depending on the type of filter in your air purifier, you might find that you’re having to replace or clean the filter more frequently if the diffuser is running alongside the air purifier. Cleaning a filter might be one thing, but having to frequently replace a filter can become quite costly.

For these reasons, it’s important to consider your individual devices, requirements, and budget before proceeding with using an air purifier and diffuser at the same time. It won’t be detrimental if you do, but there are some situations that can lessen the effectiveness of the devices as well as present other disadvantages.

Can You Put Essential Oil in Your Air Purifier?

This might seem like a good way to get around any negative consequences of running both devices at once, however it is vital that you DO NOT DO THIS. Most air purifiers are not designed to have oil inserted into them, nor to dispense oil so trying to put oil in yours can cause serious damage.

The only circumstance where this is possible is if you have a combined air purifier and diffuser, which you can find on the market. These devices are specifically created to do the job of purifying the air and distributing scent.

Final Thoughts

If after reading this you still have your doubts, why not do a little experiment? Run your air purifier and diffuser simultaneously for a day and record what kind of results you get in terms of fragrance, filter effectiveness, noise, and cost.

You can then compare these results with a day of running each device at a separate time, and see how the outcomes stack up. As states in the beginning of this post, there is no one-size-fits-all answer so the best thing to do is see what works best for you!

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