Improving Indoor Air Quality with a Rabbit Air Purifier

How we think about indoor air quality is changing due to the COVID-19 virus. According to Wikipedia, “Indoor air quality (IAQ) is the air quality within and around buildings and structures. IAQ is known to affect the health, comfort, and well-being of building occupants. Poor indoor air quality has been linked to sick building syndrome, reduced productivity, and impaired learning in schools.

“IAQ can be affected by gases (including carbon monoxide, radon, and volatile organic compounds), particulates, microbial contaminants (mold, bacteria), or any mass or energy stressor that can induce adverse health conditions.”

According to the U.S. Environmental Protection Agency (EPA), “There are three basic strategies to improve indoor air quality:

1. Source Control
2. Improved Ventilation
3. Air Cleaners”

Source control involves eliminating an indoor air pollutant where it originates. For example, mold that is growing because of excess moisture could be eliminated by fixing the source of the moisture. The moisture could be from a leaking pipe, a damaged shingle allowing water to leak through the roof, or even from the soil next to the home being improperly graded, allowing water to pool next to the foundation.

Ventilation can help reduce many indoor air pollutants. The easiest way to improve ventilation in a home is to open a window. This is only practical, however, when the weather is mild enough that it won’t impact the energy used for heating and air conditioning.

There is a wide array of air cleaners available on the market. Even the filter in a forced air furnace can help clean the air in a home. Unfortunately, COVID-19 is dramatically changing how we view the effectiveness of an air cleaner

COVID-19 was not considered to be an indoor air quality issue. It has been thought that when an infected person, for example, sneezed the virus, it would be spread in respiratory droplets that could only travel a few feet before dropping to the ground. This was the basis for social distancing guidelines that have instructed people to stay six feet apart. However, an open letter from 239 scientists states that COVID-19 can be spread by much smaller droplets produced when infected people simply sneeze, cough, talk, and even breathe. These smaller droplets can travel up to 30 feet. On July 9, 2020, the World Health Organization (WHO) acknowledged that the virus, under certain conditions, could become airborne. This means that the virus can be spread by:

• Children playing and singing outside an open window
• The person that brings you food delivery and talks to you while standing at your door handing you your dinner
• Anyone near your home.

Few air cleaners have the capability of removing viruses from the air in a home.

Introducing Rabbit Air

Rabbit Air was founded in 2004 in Los Angeles, CA. They have received numerous awards from around the world, including being a seven-time Inc. 5000 honoree, Bizrate Circle of Excellence Platinum Award for excellent service, Red Dot Design award winner in Germany, and more.

They manufacture four different indoor air purifiers:

• BioGS 2.0 SPA-550A – Three stages of filtering for rooms up to 550 sq. ft.
• BioGS 2.0 SPA-625A – Three stages of filtering for rooms up to 625 sq. ft.
• MinusA2 SPA-700A – Six stages of filtering for rooms up to 700 sq. ft.
• MinusA2 SPA-780A/N – Six stages of filtering for rooms up to 815 sq. ft.

Introducing the Rabbit Air MinusA2 SPA-780N

For this article, Rabbit Air provided me with a MinusA2 SPA-780N air purifier that includes Wi-Fi connectivity. The MinusA2 SPA-780N has six stages of air filtering. These include:

1. Washable Pre-Filter for capturing large-sized allergens, dust, and particles –including dust mites and pollen
2. Medium Filter for capturing airborne particles larger than 1 micron in size, such as bacteria, pet dander, dust, pollen, mold, fungi, and more
3. BioGS High Efficiency Particulate Air (HEPA) filter. This filter traps allergens and particles 0.3 microns in size at 99.97-percent efficiency and over 99-percent efficiency for particles less than 0.1 microns. This includes bacteria, pet dander, dust particles, exhaust fumes, mold, fungi, pollen, particles that can carry virus, and more. Rabbit Air’s filter design also reduces the growth of bacteria and viruses on the filter and prolongs optimal filter efficiency.
4. Customized Filter – This filter layer can be customized by choosing one of four different filter options including:
   1. Germ Defense Filter is designed to trap and reduce bacteria, mold spores, and particles that carry viruses
   2. Toxin Absorber Filter designed to trap and reduce volatile organic compounds (VOCs), off gassing, and chemicals
   3. Pet Allergy Filter is designed to trap and reduce pet dander and pet allergens
   4. Odor Remover Filter is designed to trap and alleviate odors from pets, cigarettes, cigars, cooking, and mildew.
5. Charcoal-Based Activated Carbon Charcoal Filter traps and reduces household odors (cooking odors, pet odors, etc.), exhaust fumes, greenhouse gasses, tobacco smoke, toxins, chemicals, and VOCs
6. Negative Ion Generator. The negative ions produced in this filter layer attach to particles so they are weighed, settle to the floor, and can be picked up by a vacuum. With the Negative Ion Generator turned off, the air purifier does not produce any ozone. With it enabled, the MinusA2 SPA-780N meets the stringent California Air Resources board safety standards for ozone production.

The filter pack is estimated to last up to 12 months when running the air purifier 24/7. A replacement kit that includes the Medium Filter, BioGS HEPA Filter, Customized Filter, and the Charcoal-Based Activated Carbon Filter is available directly from Rabbit Air for $85. It can be ordered either as a one-time purchase or on a subscription basis.

The MinusA2 SPA-780N has been certified asthma & allergy friendly by the Asthma and Allergy Foundation of America (AAFA) and Allergy Standards Limited (ASL).

The MinusA2 SPA-780N has a number of other unique features:

Intelligent Purification on the MinusA2 SPA-780N

All of the functions of the MinusA2 SPA-780N can be controlled through a smart phone app. This includes the ability to adjust the air purifier’s speed and mode, set an operating schedule, adjust the air purifier’s light settings, monitor the indoor air quality with the air purifier’s built-in sensors, check the filter status and receive a notification when they need to be replaced.

When operating in Auto Mode or Pollen Mode, the air purifier’s built-in odor and particle sensors can automatically adjust the fan speed based on the level of pollutants detected. When it senses particles and/or odors in the air, it will automatically switch the fan to high speed, moving more air through the filter, to more rapidly clean the air. Once the sensors detect a reduced level of pollutants the air purifier will resume operating at Silent Speed.

In Manual Mode, the air purifier’s fan will simply run based on the selected speed. In Pollen Mode, the fan speed will be adjusted based on the detected air quality. Finally, in Auto Mode, the fan speed will be adjusted based on the detected air quality unless the light sensor has enabled Sleep Lighting. In this case, the fan speed will stay at Silent Speed.

The MinusA2 SPA-780N can also be controlled through Alexa voice commands with the Rabbit Air skill. You can turn the air purifier on/off, set the fan speed, set the lighting, ask for the air quality, and much more.

Light Sensing on the MinusA2 SPA-780N

A built-in light sensor automatically adjusts the MinusA2 SPA-780N’s indicator lights based on the ambient light in the room. It changes the indicator lights output to a low-energy dimmed sleep lighting level when the room darkens to reduce light pollution. During the day it restores the indicator lights to their normal output making them easy to read.

Low Cost of Ownership of the MinusA2 SPA-780N

The Rabbit Air MinusA2 SPA-780N is inexpensive to operate when compared to other competitive products. First it is Energy Star rated so the cost of the electricity required to operate it is minimized. Second, the annual cost for the filters is less than most of its competitors. The total annual operating cost is less than $150 with the air purifier running 24/7. This includes both the cost of annually replacing the filter pack and the cost of electricity to operate the purifier.

The MinusA2 SPA-780N is Ultra Quiet

Rabbit Air uses Brushless Direct Current (BLDC) motors for near silent operation. In silent mode the MinusA2 SPA-780N produces only 25.6dBA. This is between the amount of noise produced by a clock ticking and a person whispering.

MinusA2 SPA-780N is Wall Mountable

The slim 7-inch depth of the MinusA2 SPA-780N allows it to either be placed on the floor or mounted on a wall. If it is wall mounted, there are decorative art panels available to turn the purifier into a feature point in a room. There is also an LED mood light on the front panel. It produces different colors based on the operating mode of the air purifier. For example, in Auto Mode, the light is blue but in Pollen Mode the light cycles from blue to purple to light purple to pink.

Hands-on with the Rabbit Air MinusA2 SPA-780N

Rabbit Air supplied me with a MinusA2 SPA-780N to test for this article. Customers can request that the air purifier be fully assembled at the factory so you can just plug it in, and you are ready to go. In the box with the air purifier are a wireless infrared remote control and a bracket so you could mount the unit on a wall.

The remote control includes buttons to:

• Turn the unit on/off
• Control the fan speed
• Change the operating mode (Pollen Mode, Auto Mode)
• Mood light on/off
• Negative Ion on/off

The MinusA2 SPA-780N also can be controlled using the Rabbit Air smart phone app. Setting this up was very simple. After downloading the app and opening it, the app will guide you through the process of creating a Rabbit Air account. Next, you scan the bar code on the back of the unit using the phone’s camera. Then you connect to the a Wi-Fi SSID being broadcast by the unit and select the Wi-Fi SSID of your home’s Wi-Fi network along with its password. The MinusA2 SPA-780N will then connect to your network and you can begin controlling the unit using the smart phone app.

If you don’t have either the remote or your smart phone handy, the air purifier can also be controlled through buttons on the front panel. These buttons allow you to control the fan speed, mode, and turn the mood light on/off. In addition:

• Pressing and holding the Mode button will reset the Filter Replacement indicator light. The Filter Replacement indicator will automatically be lit after the purifier’s internal timer calculates that the filter has been used for the equivalent of one year of continuous operation. Once the filter has been replaced the homeowner will be required to manually reset the indicator using these buttons.
• Pressing and holding the Speed button resets the Wi-Fi connection to broadcasting the units SSID so it can be connected to a new Wi-Fi network
• Pressing and holding the Mood Light button will turn the Negative Ion Generator on/off
• Pressing and holding both the Speed and Mode buttons allows you to change the sensitivity level of the sensors

Also on the front panel are:

• Light Sensor. After the sensor detects darkness for three minutes it will activate the Sleep Lighting feature. When Sleep Lighting is active the mood light will be turned off and, if the air purifier is operating in Auto Mode, the fan will be set to Silent Speed. In Pollen Mode the Light Sensor is ignored and the fan speed is simply adjusted based on air quality.
• Air Quality Indicator. This color-changing indicator visually shows the air quality detected by the units particulate and VOC sensors. The color of the indicator will change from blue (good – low count of particulates) to purple to light purple to red (poor – high count of particulates).

When I first received the MinusA2 SPA-780N I was surprised that it wasn’t indicating that the air quality in my home was good. This conflicted with readings from several other air quality sensors I have. Simply following the instructions in the manual for cleaning the particulate sensor with a Q-Tip solved the issue. I expect there was simply some dirt on the sensor left over from manufacturing or transportation.

The Rabbit Air app provides an easy to use interface for controlling even more features of the MinusA2 SPA-780N. You can:

• Turn the unit on/off
• View the Air Quality
• Control the fan speed
• Auto Mode On/Off
• Set the sensitivity of the air quality sensors (low, medium, or high)
• Pollen Mode On/Off
• Mood light on/off
• Turn all front panel lights off, Set their state to be determined by Light Sensor, Turn all the front panel lights on
• Negative Ion on/off
• Enable a 2-, 4-, 6-hour, or custom length time
• Set a schedule where the unit will operate at a specific fan speed on an hour by hour basis
• View a bar graph of the filter life
• Order replacement filters
• View product videos
• View frequently asked questions
• Contact Rabbit Air (automatically dials their phone number)
• Add address info to your account
• Reconfigure the unit’s WiFi connection

My one wish for the app is that it would provide separate air quality readings from the two sensors (particulates and VOCs). Understanding specifically what the air quality issue is in your home allows you to take steps to mitigate it rather than just relying on the MinusA2 SPA-780N to filter the air to solve the problem. This would allow people to use the unit as an indoor air quality monitor and save owners the cost of purchasing a separate device.

My first test of the MinusA2 SPA-780N was to place it in the corner of my bedroom behind some furniture. That spot doesn’t get vacuumed often enough and I probably kicked some dust up moving things around to get the air purifier settled in place. When I plugged the air purifier in the air quality indicator immediately turned red. The MinusA2 SPA-780N was in auto mode so, as expected, it turned the fan speed to High to clean the air as quickly as possible. After a minute some of the dust was cleared from the air, the Air Quality Indicator changed to light purple, and the fan speed was reduced. Later, it changed back to Blue and the fan speed changed to Silent.

I used the MinusA2 SPA-780N in my bedroom for several days to evaluate it in the same environment as any homeowner. People spend a significant portion of every day in bed, so the bedroom is a very reasonable place to test the MinusA2 SPA-780N. The bedroom is also a place where people want an air purifier that performs well but doesn’t impact their ability to sleep.

The MinusA2 SPA-780N offers a Silent Mode of operation. In Silent Mode, the fan operates at a slower speed that makes much less noise. However, the slower fan speed also moves less air through the air purifier’s filters so it will be less effective at cleaning the air in a room. The built-in light sensor allows the air purifier to automatically change to Silent Mode whenever the room it is located in is dark. Unfortunately, this means that the air purifier will go into silent mode as soon as the sun goes down and will come out of silent mode as soon as the sun comes up. So, in the summer, when days are longer, the sun might come up as early as 5:30 a.m. and you could be woken up very early when the fan speed automatically increases in response to the built-in sensors. In the winter, when the sun goes down very early, the air purifier will run in silent mode for the entire evening, making it less effective at cleaning the air in the room.

The MinusA2 SPA-780N also offers the ability to create a built-in schedule that can work around this issue. You can schedule specific fan speeds at different times of the day. This is a reasonable alternative when using the air purifier in a bedroom. You can schedule the unit to operate in Silent Mode during the hours you are in bed. This is the optimal way to operate the MinusA2 SPA-780N. You can schedule it to operate in Silent Mode at night and at a higher fan speed during the day to maximize the air flow through the purifier and the how often all the air in the room is cleaned.

In addition, I don’t spend any time in my bedroom during the day so there isn’t really a need for air purifier to run at all. My ideal schedule would be for the unit to:

• Be turned off during the day to save electricity and to maximize the life of the filters
• Turn on in Auto Mode during the evening to catch up and make sure the air in the room is clean before I go to bed
• Operate in Silent Mode during the hours I’m in bed

Of course, if the MinusA2 SPA-780N were located in a different room of my house the schedule would be different. In a family room you would want the air purifier running during the day but could save energy and extend the filter life by turning it off at night when family members are asleep. In either case, the ability to schedule times when the unit is off and to schedule times when the unit operates in Auto Mode would be nice enhancements to the built-in scheduler.

The above are really minor usability issues with what I was otherwise finding was an excellent product. To really see how effective the MinusA2 SPA-780N was at cleaning the air, I came up with torture test on its effectiveness at removing particulates from the air.

The only issue I had with the MinusA2 SPA-780N was that it would periodically disconnect from the Wi-Fi in my home. This was attributed by Rabbit Air support to a level of incompatibility with my home’s mesh Wi-Fi. Since the MinusA2 SPA-780N, for the most part, takes care of itself when in Auto Mode, it didn’t really impact me. Had I not been testing all the different aspects of the air purifier, I might not have noticed for quite some time.

In any case, fully powering off the unit, followed by a reset of the Wi-Fi settings, was all that was required to reconnect it to my router using the smart phone app.

MinusA2 SPA-780N Integration with Amazon Alexa

The MinusA2 SPA-780N does support Alexa voice commands. Using the Alexa app, you can enable the Rabbit Air skill and link it to your Rabbit Air account with a pass code that Rabbit Air will email to you. Once this is done you can use either the Alexa app or voice commands to control your Rabbit Air purifier.

One thing to keep in mind is that for some of the voice commands to work, you need to remember the unique name you assigned your Rabbit Air purifier in the smart phone app when you set it up. With this you can use commands such as:

• Alexa, turn on/off [air purifier name]
• Alexa, set [air purifier name] to [auto low or auto medium or auto high]
• Alexa, turn on/off the mood light on [air purifier name]
• Alexa, what is the air quality on [air purifier name]

A full list of the available voice commands can be found here: https://www.rabbitair.com/pages/alexa-commands-for-minusa2-spa-780n

Smart Home Integration of the MinusA2 SPA-780N

I wasn’t able to create a Crestron integration module to communicate with the MinusA2 SPA-780N as part of this article. That may be coming in the future. However, the MinusA2 SPA-780N can be somewhat automated using a simple smart plug.

If you remove and restore power to the MinusA2 SPA-780N, it will return to its prior settings. So, by simply leaving the air purifier in Auto Mode and powering it on/off using a smart plug you can turn the air purifier off when the home isn’t occupied and turn the air purifier off when the area of the home it is located in isn’t being used. Then, when the smart plug is turned on Auto Mode, it will take care of utilizing the sensors in the device to set the fan properly based on the air quality in the room.
Conclusions from Testing the MinusA2 SPA-780N

In a recent article in CNET, Will air purifiers protect you from COVID-19, wildfire smoke and pollen?, there were some very valid points explored on the limitations of air purifiers. For example, no air purifier is going to protect you from close contact with a person with COVID-19. But, air purifiers do have a place in COVID-19 prevention based on the latest research showing that the virus can be spread by small droplets that can remain in the air for longer periods of time and travel up to 30 feet. In addition, as someone who is both an allergy sufferer and lives in an area of the country that is plagued by late summer wildfires, air purifiers definitely have their place in making significant improvements to the air quality in a home.

The Rabbit Air MinusA2 SPA-780N isn’t an inexpensive investment and offers a wide array of features and high performance air filtration.