If you’re trying to improve air quality in your home, then you know there are many products and techniques available to achieve different results depending on your goal. But when thinking about controlling everything from humidity levels to particulate matter and floating allergens, the list of contaminants and potential issues can be daunting to homeowners and renters alike.

Here we will focus on 3 common air quality products—air purifiers, humidifiers, and dehumidifiers. We want to help you choose useful tools to improve your air.

What is the Difference Between an Air Purifier and Dehumidifier?

Air purifiers clean the air by removing pollutants. Air passes through the purifier’s various filters that hold or remove pollutants so that only clean air is emitted back into the room. Depending on the technology of the product, some air purifiers can have better performing filtration systems. An air purifier’s purpose is to “clean” the air; it does not and cannot change household humidity levels.

Dehumidifiers work to maintain healthy and preferred humidity levels by removing excess moisture from the air. Dehumidifiers can prevent mold and bacteria from growing by creating a less optimal environment for those pollutants to thrive in.

Humidifiers serve the opposite purpose of dehumidifiers. They introduce moisture into air that feels “too dry” in certain seasons.

How Do I Know if I Need an Air Purifier vs Dehumidifier?

Since air purifiers and dehumidifiers perform different tasks for your home, there’s nothing wrong with having both. But if you notice any of the following symptoms in your home, it is definitely time to invest in a dehumidifier:

• Windows show condensation on the inside, especially in the mornings
• Rooms feel stuffy, the air feels heavy
• You smell mustiness or mold when you enter a room or area
• You can see moist or damp stains on walls, ceilings, or other surfaces

Is High Humidity Bad?

High humidity is bad for many reasons; it can impact everything from your health to your home. A dehumidifier will work to prevent or remediate most of these problems by removing extra moisture from the air. Here are some situations where a dehumidifier can help lower high humidity and improve air quality:

• Mold remediation and prevention – mold thrives in conditions over 60% RH, so if you’re noticing a musty smell, mold growth, or if your symptoms are related to your health, consider checking your humidity levels or even calling in the experts to check for mold. A dehumidifier will help lower humidity levels to prevent mold from growing.
• Dust mites – since dust mites enjoy humidity, creating a hostile environment for these invisible allergens can lower their levels and ease allergy-related symptoms. They cannot survive below 50% RH.
• Asthma – because asthma attacks can be triggered by air pollutants, a dehumidifier will ensure your humidity levels are kept low enough to minimize the growth of bacteria, dust mites, and mold.
• Structure and furniture – overly high humidity levels can affect the structural integrity of your home. Wood can rot from excessive moisture while metalwork can begin to rust. Even furniture can gather bacteria and dust mites or start to smell musty. High humidity can also create unseen problems, like the ones hiding in the ductwork of your home.

There are some situations where you may need to increase humidity levels, supporting that a humidifier can be used in some situations to improve air quality. Here’s where a humidifier vs dehumidifier is actually a better solution:

• Newborns – if you have a baby, then a humidifier can make a good addition to a nursery. Humidifiers can increase moisture in dry air that would otherwise exacerbate scratchy throats and noses, especially during the drier winter months.
• Illness – According to researchers from the NIH, National Institutes of Health, humidity levels can limit the spread of Covid-19 and other airborne viruses. Increased humidity can also make symptoms of some illnesses feel less severe. Be cautious, though, of increasing humidity too much, or for too long.

Can I use an Air Purifier and Dehumidifier Together?

You definitely can use an air purifier and dehumidifier (or humidifier) simultaneously. An air purifier and a dehumidifier actually complement each other when used simultaneously. One thing to keep in mind if you use a humidifier is that it shouldn’t be placed too close to an air purifier. Since a humidifier expels moisture into the air and an air purifier works to filter the same air, if the two are placed side-by-side the air purifier to will accumulate moisture within its filters. If an air purifier’s filters become moist this creates an environment for bacteria and mold spores to thrive; the air purifier will then be unable to properly filter the air and will instead distribute the very pollutants you were hoping to minimize.

What to Do?

Now that you’re more familiar with the differences between an air purifier and dehumidifier, you can begin to assess you home and goals to determine which is best for your situation. Keep in mind that an air purifier can be used year-round while a dehumidifier or humidifier is typically only used for shorter periods of time. Dehumidifiers are often used during the spring and fall seasons, when it is cool but humid outdoors; they might also be switched on during especially humid summer months. And, of course, both can run while an air purifier works to address air pollutants.

Learn more about how air filters, air purifiers, and air scrubbers work in different ways to improve indoor air quality.