A passive house in a COVID world

view of our house from the surrounding Altshul Preserve

The Corona Virus has shaken up our lives. Fortunately, construction in Connecticut has been allowed to continue since Connecticut went on “pause” and my husband, son and I were able to move into our new house several weeks ago. Living in a passive house means that you live in a house with exceptional air. Unlike traditional residential heating and cooling systems which recirculate air, passive houses receive fresh air 24 hours, 7 days a week through a heating and cooling system called Energy Recovery Ventilation. This air is filtered with a state-of-the-art system which removes pollutants including dust, bacteria and some viruses.

Our ERV unit takes up minimal space and has no sound

For many homeowners, leaving the office for home meant reducing the quality of the air they breathe. Whereas buildings are required to comply with national guidelines such as The American Society of Heating, Refrigerating and Air Conditioning (ASHRAE), residences don’t have these rules. Also, a heating and cooling system in a building is designed by a licensed engineer whose job is to ensure these standards are met and whose design incorporates the latest technology to improve air quality. Most houses do not have HVAC systems that were designed by licensed engineers but were recommendations from contractors who may be knowledgeable, but don’t have the insight of a trained mechanical engineer. But air quality can be significantly improved in any house using some of the technology we used in our house. Here are a few concepts.

Particulate matter or particle pollution is inhaled into the lungs and can cause permanent health damage; good air filtration captures this pollution before entering the house.

Air Filters:

Every house has a filter that works with the furnace if there is no air conditioning, or with the HVAC system if their is central air cooling and heating. There are different types of filters and the quality varies. Also, filters need to be replaced usually every three to four months. Pleated filters that have a “minimum efficiency reporting value” (MERV) of 8 and above will successfully filter out particulate matter, or particle pollution. The higher the number the better the filtration:

MERV 8: filters humidifier dust, hairspray, mold spores and pet dander

MERV 13: provides additional filtration of smaller particles including bacteria, saliva and some viruses

Our house has MERV 13 filtration. When we moved in we realized that the filter had not been changed at the end of construction and the filter installed was stuck with debris. Also, our contractor had intended to install MERV 8 filtration instead of MERV 13. Our own research helped us improve the air quality in our house.

There are higher numbered filters, such as MERV 14, that are called HEPA (High Efficiency Particulate Air) filters. These filters need more fan power to work and because of this aren’t common in residential design. HEPA filters have traditionally been used in healthcare. Since COVID some commercial buildings are retrofitting their HVAC systems to use HEPA filtration. HEPA filtration is now however available in air purifiers and vacuums.

Air purifiers and HEPA vacuum cleaners

Improving air quality through your HVAC unit is great but trapping the particle pollution brought in by walking indoors from outside is of equal importance. One of the most insidious pollutants brought in from outdoors are dust mites, microscopic bugs that thrive by eating house debris like the skin that we shed every day. Unless you live in an area with no humidity like a desert (dust mites cannot survive in that climate) you have dust mites. The allergens they leave in a house are considered to be the major biological agent for the development of asthma. Both air purifiers and HEPA vacuum cleaners are superb in controlling these indoor pollutants. There are hundreds of brands: Dyson is one of the best and my preferred manufacturer.

Air purifiers

Air purifiers “purify” the air by trapping the smallest particle pollution including smaller viruses.

Two types of purifiers are:

HEPA Air Purifiers: HEPA filters trap 99.9% of airborne pollutants up to .03 microns (COVID 19 measures .01-.03)

Ultraviolet Light Air Purifiers: By using radiation from UV lights, airborne pollutants passing through the light is killed.

Dyson’s Pure Humidify + Cool PH01 uses carbon and HEPA filtration and controls humidity

Vacuum Cleaners with HEPA filtration

There are now vacuum cleaners available with HEPA filters which are superior when it comes to trapping pollutants such as dust mites. These filters also trap the smallest air pollutants including most bacteria, and some viruses. I recently bought a vacuum made by Dyson. with HEPA filtration.