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Home Ventilation and COVID-19: How ventilation prevents the spread of COVID-19 indoors



    For the past six months, Chicagoans have been bombarded with officials’ implorings to wash their hands, stay six feet apart and wear a mask.  And in turn, the ‘three w’s’ have certainly helped to curb the rise of COVID-19 in some areas of Illinois. But as the coronavirus is new (although it seems like it’s been here forever), scientists are continuing to learn new things about it and its transmission. The latest coronavirus topic? How ventilation prevents the spread of COVID-19 indoors. 

    The research to this effect is definitely sound. In July, 239 scientists from 32 countries wrote an open letter to the WHO showing evidence that tiny virus droplets people expel when they cough or sneeze can hang in still air for hours, making crowded indoor spaces with poor ventilation risky for the spread of COVID-19. 

    Then, in late August, a team of infectious-disease experts argued in a new analysis in the peer-reviewed medical journal, BMJ, that six-feet protocols are too rigidly small and are based on outdated science and studies of different viruses. Instead, these experts now believe the evidence shows that the novel coronavirus can travel farther than six feet under certain conditions and that six feet is the bare minimum of space that should separate people, especially in poorly ventilated indoor areas.

    So as Autumn approaches and Chicago area residents start to return to school and work and begin spending generally more time indoors, good home ventilation will be key to prevent the spread of COVID-19 indoors. Here’s how to ensure proper ventilation and stop the spread of the virus:

    Keep it Fresh

    Trust your nose. If you walk into a room or building where the air feels stuffy and stale, turn around and leave because chances are, the ventilation is insufficient. And without proper ventilation, COVID-19 could spread indoors. 

    Simply put, the more outside air that enters a building, the better. Bringing in fresh air dilutes any contaminant in a building, whether a virus or something else entirely, and reduces the exposure of anyone inside. “Having 100% outside air or close to 100% is a good thing,” says Prof Cath Noakes of the University of Leeds. “The more fresh air, the less you’re running the risk of recirculating the virus through the building.”

    In warm weather, it’s pretty easy to get a larger amount of outside air into a building by keeping windows and doors open (or cracked if the AC is on) and by putting a box fan in a window blowing out which can greatly increase the air exchange rate.

    In cold weather, try micro-ventilation. This means that you just crack open one window in each room to permit a little fresh air to enter. To help keep the room warm, switch ceiling fans to “winter” mode. Most ceiling fans have a switch that reverses the blade direction. This reversal pulls the cold air up and pushes the warm air downwards.

    Check the Air Conditioner

    If a building you enter has a split air conditioner (a slim white box mounted on a wall or ceiling), try not to spend too much time there or you might risk COVID-19 spreading indoors. All air conditioners recirculate air, but smaller ones like these don’t have the filtering capacity of larger, outside units.

    For your Chicagoland home HVAC, it’s recommended using a MERV-12 level filter that removes particles down to 1.0–3.0 microns as a good medium between effective filtration and likely compatibility with your existing equipment. (Note: Since higher-rate filters allow less air to flow through your furnace, it’s a good idea to check if your system has a maximum MERV rating. The wrong type of air filter can force your furnace to work harder and increase the risk of it breaking down.)

    Use Air Cleaners

    Lew Harriman, director of research & consulting at HVAC consulting company Mason-Grant, and a member of the ASHRAE Epidemic Task Force, says concerning filtration, “Don’t let the air conditioner carry that load. Frankly, you should have an air purifier even if you’re not concerned [about airborne viruses].”

    Air purifiers remove particles from the air, usually using a filter made of tightly woven fibers. They can capture particles containing bacteria and viruses and can help reduce disease transmission when used along with other best practices recommended by CDC and others. But not all air purifiers are equal. Here are some points to keep in mind:

    • Your best option is a cleaner that uses a high-efficiency particulate air (HEPA) filter, as these remove more than 99.97% of all particle sizes
    • Think about how powerful an air cleaner you’ll need. The bigger the room – or the more people in it – the more air needs to be cleaned.
    • Scrutinize the validity of the claims made by the air cleaner manufacturer. The Association of Home Appliance Manufacturers (AHAM) certifies air cleaners, so look for their verified seal.

    Use a CO2 Meter

    Since the coronavirus is most often spread by breathing, coughing or talking, you can use this meter that checks CO2 levels to see if the room is filling up with potentially infectious exhalations. A well-ventilated room will have around 800 ppm of CO2. Higher numbers are a sign the room may need more ventilation.

    Good air quality is just one way to help protect yourself, your families and coworkers. A higher air quality helps prevent the spread of COVID-19 indoors. The EPA states, “By itself, increasing ventilation is not enough to protect people from COVID-19. When used along with other best practices recommended by CDC and others, increasing ventilation can be part of a plan to protect people indoors.” So use ventilation alongside following the rest of the CDC’s guidelines; social distance, wash your hands, wear a mask, and treat frequently touched surfaces with disinfectants.

    ServiceMaster Restoration By Simons can help with two of those guidelines. First, we’re able to help properly disinfect and decontaminate your home or facility as we provide Decontamination Services to commercial and residential properties across Chicago. Second, we provide Air Duct Cleaning Services. The EPA found indoor air may be two to five times—and occasionally more than 100 times—more polluted than outdoor air and may cause health problems. To improve the function of your air purifiers, have us clean your air ducts regularly. That way you’ll be able to breathe easier – both literally and figuratively.

    ServiceMaster Restoration By Simons is an MBE/WBE certified firm and family-run company serving Chicago, Oak Park/River Forest, and the North Shore.  ServiceMaster Restoration By Simons provides Disaster Restoration Services including  COVID-19 Cleaning Services, Water & Flood Damage Restoration, Fire & Smoke Damage Restoration,  Mold Remediation, and a wide range of interior specialty cleaning including Hoarder & Clutter Cleaning,  Post-Construction Cleaning,  Carpet Cleaning, and Upholstery Cleaning to residential and commercial customers. ServiceMaster Cleaning By Simons provides Specialty Cleaning Services For Chicago, Oak Park-River Forest, and the North Shore.  For more information, give us a call at 773-376-1110 or visit


    • Sam Simon

      Sam Simon is a very accomplished individual. He is gifted in the areas of creativity and operations - managing and directing restoration of large commercial losses to the every day residential water damage. He recently achieved the coveted title of Master Restorer by the IICRC (Institute of Inspection Cleaning and Restoration Certification) after countless hours of classroom training & education. Sam is knowledgeable on a vast range of disaster restoration topics from water damage/flooding, mold remediation to advanced drying, fire & smoke restoration, and specialty cleaning (carpet and upholstery). Given Sam's background in the television industry as a videographer and cameraman, he lends a creative flair to the company's strategy marketing planning efforts and is well regarded in the restoration industry.

      About ServiceMaster Restoration By Simons
      Restoration By Simons is an MBE/WBE certified firm and family-run company serving both Cook and Lake County, Illinois. Recently, the company was awarded a variety of honors, including the SB100 Best of Small Business Award Winner 2021, Bronze Stevie® Award in the Female Entrepreneur of the Year category in the 18th annual Stevie Awards for Women in Business, recipient of the 2020 Better Business Bureau's Torch Award for Marketplace Ethics, and the recipient of the 2020 Skokie Business of the Year Award, Honorable Mention Category. Restoration By Simons provides disaster restoration services including water and flood damage restoration, fire and smoke damage restoration, mold remediation, to residential and commercial customers in both Cook and Lake County IL.

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