Informational Guide

Do Mini Splits Bring Fresh Air Into The Home?

A mini-split air conditioner is a great addition to your home. Learn about the air circulation and how fresh and clean it really is.

by Josh M

A mini split air conditioner (AC) is a great addition to your home – it provides cooling and heating in areas central AC’s may not reach. They are also good for smaller homes to keep you cool.

But do they bring in fresh air into the home? How do they work exactly? This guide will discuss what a mini split AC does to the air inside your home.

In short – no.

In a Daikin AC mini split, the indoor air handler draws air already in your home to a refrigerant, which turns it into gas. This is sent to the heat pump and expels the hot air from the system, reactivating the refrigerant. This pumps cool air back into your home.

This will work in reverse for the winter, using all heat available. If the air isn’t being pumped in, then what exactly happens to the air outside?

Brown Brick Wall with Split Air Condenser

How a Mini Split AC Processes Outside Air

As we know, the air isn’t filtered from outside. The cooling coils inside the evaporator use the refrigerant to cool the air and send it to the compressor outside. This, in turn, is sent through refrigeration tubes to the outside compressor.

While in the compressor, the refrigerant is sent through heating coils and reforms into liquid. This is where the fan extracts the heat and sends it outside. The refrigerant is passed through an expansion valve, which controls the amount of refrigerant returning to the evaporator.

In short, the compressor in a mini split recycles the air from inside your home and cools it to the desired temperature through the rapid heating and cooling process.

Read about our favorite mini-split models here

How a Ductless Mini Split System Can Improve Air Quality

A ductless mini split system works both ways; it’ll keep you warm in winter and cool in summer. But the benefits don’t stop there. The quality of your air is improved with the system, which we will explore below.

Multi-Staged Filtration

The air handler has air filters installed to catch small particles. They filter out pollen, mites, dander, and other allergens that could affect your breathing. The air sent through the compressor doesn’t include any additional air, meaning the cooled air is cleaned and better for your lungs.

Controls Humidity

The refrigerant absorbs and holds the excess moisture. Before it’s sent outside, the moisture is condensed and drained through the drain pump on the side. This means the air flowing into the room isn’t adding excess moisture. Mini split systems also work well with dehumidifiers if a room is particularly humid.

Removes Pests & Pollutants

Because it’s installed with a small conduit line, it’s sealed off from the outside. Unlike a windowed AC, bugs, pollen, and outside pollutants can’t slip into the system. This will give you peace of mind that you’re breathing better quality air and easing stress on your lungs.

No Ducts

Unlike a standard central AC system, the mini split AC doesn’t have a duct system that is connected through the house. Ducts tend to build up bacteria, dust, and insect droppings as the years go on, and require cleaning or maintenance to stop leaks. Mini splits eliminate all the potential hazards associated with ducts.


A mini split AC system can be installed anywhere – in any room, on the ceiling, walls, or floor. If you’re so inclined to, you can install multiple systems to keep the air around your home clean as a whistle.

Air Conditioner AC Cool Cooling

Other Easy Ways to Improve your Indoor Air Quality

Open Doors & Windows

Keeping the air flowing through your home is important. Letting in the fresh air through your windows and doors will let clean air in while pollutants and allergens go out. Cleaner air will also filter through a mini split system as a result.

Use Natural Cleaning Products

A lot of our cleaning products at home contain a number of toxic and potentially hazardous chemicals that do more damage to the air. Instead, try opting for eco-friendly, non-toxic cleaning products to reduce this. Consider making a solution of warm water, white vinegar, and essential oils.

Invest in Houseplants

Indoor plants actively absorb the pollutants inside the home and release fresh oxygen. They’re a good way of regulating clean air while sprucing up the room they’re in.

Sweep, Dust & Vacuum Regularly

Keep dust, mites, pet hair, and other irritants out of the air by vacuuming carpets and sweeping floors and dusting surfaces regularly. This will improve your air quality and reduce the levels of allergens in the air.

Replace AC Filters

If you have a duct system, pollutants and bacteria will build up in your filters over time. Make sure to check and replace your filters regularly to avoid them being filtered into the air.

People Also Ask (FAQ)

Do mini-split systems filter smoke?

A mini split AC system will filter out the pollutants in your air when it’s drawn in, so it will also clear out any smoke in your home or garage. This works well but we also recommend a specific air purifier to deal with smoke issues.

What does dry mode do on a mini split?

Dry mode is designed to slow the speed of the fan, giving the coils more opportunity to filter out moisture from the air, creating a better dehumidification process.

Is it okay to run AC with smoke outside?

Yes – the air is filtered through the mini split system, which means harmful pollutants and smoke won’t be brought into your home.

 How long will a ductless system last?

Depending on how often you use it and if you have it maintained regularly, your system should work for up to 20 years. Check out our reviews of these popular models to learn more.


Ductless, mini split air conditioners seem like a no-brainer when it comes to cleaner air. While it does not bring in fresh air from outside, it will recycle and improve the indoor air while controlling the temperature of your home. Gone are the days of being too cool or too hot, and cleaner, breathable air is an excellent bonus.

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.