What's the difference between air scrubbers and air purifiers?

What is the difference between an Air Scrubber and Air Purifier?

Did you know we spend over 90% of our time indoors? The bad news is the air we’re breathing indoors may not be as fresh as you may think. According to the EPA, indoor air can be as much as 5 times more polluted than outdoor air. You may be thinking you need a whole house air purifier!

Homes are being constructed “tighter” than ever with better seals, improved insulation, and less porous materials. While this results in a more efficient home, the paths for fresh air to get in are limited – and the same for polluted indoor air to get out. Normal activities like cooking, cleaning, and sweating in your home gym add pollutants to your indoor air. Without any fresh air being introduced to your home, the air in your home is simply recirculating. Traditional air filters only capture larger dust particles – the smaller airborne contaminants will still be in the air you and your family is breathing.

Fortunately, there are technologies available for whole house air purification. At Advent, we offer two different types of technologies to our Dallas/Fort Worth customers for their indoor air quality needs: Air Scrubbers and Air Purifiers.

Let’s talk about dust atoms

Before we dig in to how these technologies work, let’s revisit a bit of chemistry basics. Recall that molecular atoms consist of positive, neutral, and negative elements called protons, neutrons, and electrons. An atom is neutral if it has equal numbers of protons and electrons. An ion is an atom that has missing or extra electrons. When an atom is missing electrons, there are more protons in that atom so it is called a positive ion. When an atom has extra electrons, the atom is a negative ion. An atom will always seek to be neutral. So, when an atom is ionized, it will seek out another ion to bond with to become a stable and happy atom.

This is important, because most pollutants in the air have a positive charge. To truly clean the air at the molecular level, we need to infuse the air with negative ions. Both air scrubbers and air purifiers use negative ionization to wipe out contaminants, but the approach is different for each technology.

What is an Air Purifier?

An air purifier is an air cleaning device that captures and kills contaminants within the purifier itself. The air purifier is installed inside your existing ductwork. As air recirculates through your air handler it passes through the device.

The first component in an air purifier is an ionization array, which creates both positive and negative ions. Then the polluted air – along with the positive and negative ions – then passes through a fiber filter material that has been electrically charged. The electrical charge causes the positive and negative ions to separate – like positive and negative ends of magnet. This process is called polarization. The ions then attach themselves to opposite sides of the filter.

‘The air particles within the pollutant atoms suddenly become attracted to both sides of the filter – seeking to join up with the positive ions or the negative ions. This causes the atom to stretch and ultimately separate – destroying the pathogen. Finally, air travels through a filter with an high MERV rating – capturing any larger particles that were not destroyed by the electrical ionization process.

So, do air purifiers work? In a word, yes. dirty air enters the air purifier, and clean air leaves it. After several recirculations of the air in your home, all of the air will become pure.

Our Comfort Care Advisor Sarah shows a customer an Air Scrubber.

What is an Air Scrubber?

An air scrubber is an air cleaning device that utilizes a search and retrieve method to eliminate contaminants in indoor air. As air flows through your ductwork system, the air scrubber continuously produces negative ions. Those negative ions are sent out on a mission to find and bring back the pollutants floating in your air that are too small to be captured by your normal air filter.

To create the negative ions, an Air Scrubber contains small metal tubes. The tubes are arranged in the shape of a honeycomb which have a special coating. Air travels through the tubes and then passes through a section that contains an ultraviolent (or UV) light. As a result negative ions are created and sent on their way to clean your air.

Once the negative ions are in the air in your home, they seek to match up with positively charged particles, like bacteria, pollen, or other allergens. When the negative ions and positive particles bond, they create larger, heavier particles that can no longer float in the air. Instead, they fall to the ground or on surfaces. When your air handler’s fan is turned on, it will pull the newly-formed, larger dirt particles through your ductwork system, ultimately landing and sticking to your air filter.

During the first week of operation – while the air scrubber is first cleansing your home’s air – you may notice an increase in dust around your home which can be swept, vacuumed, or wiped up. Think of this like a one-time spring cleaning. After the first operation, you shouldn’t notice much dust at all.

To summarize, the air scrubber creates ions that do the heavy lifting within the spaces of your home, with the dirt and particles coming to their final resting place on your air handler’s filter.

So, which air cleaner is right for me?

Both air purifiers and air scrubbers use the chemistry of ionization to clean the air. This means that both devices will deep-clean your air, eliminating up to 99% of airborne particles. If you are seeking to purify the air in your home, both choices will get you there.

The advantage to an air purifier is that the cleansing process happens within the device itself. Pure air leaves the device, delivering clean, fresh air to your space immediately after installation. On the downside, an air purifier will require regular maintenance to replace the high-efficiency MERV filter. Filters of a higher MERV rating – which are the kind that air purifiers have – will be more expensive than the more common air filters used in an air handler.

By comparison, the air scrubber does not have any components that will require regular replacement – set it and forget it. And while it may seem disconcerting that the cleansing work is happening in your space rather than within the device itself, the air scrubber has a key advantage in the fact that the negative ions will also attach to particles on surfaces in your home like countertops, doorknobs, and light switches. An air purifier can only clean particles that are airborne. So – if you are seeking both clean air and clean surfaces, an air scrubber is the way to go.

Advent Air Conditioning offers both air purifier and air scrubber technology to our Dallas/Fort Worth customers. Contact us today to discuss your home’s indoor air quality with one of our comfort advisors.


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