Chris D. Craiker: Improving home ventilation

home ventilation Improving

CHRIS D CRAIKER AIA/NCARB

With all the false data and lack of national leadership, the one thing we know is COVID-19 is airborne, mostly transmitted via tiny particles or droplets that hang in the air often for hours. Indoor activities with people in tight conditions are undesirable. It comes down to air cleanliness and sanitation. An air supply is essential for our lives, homes, businesses, schools and shop-

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CRAIKER They must be safe and hygienic. The easy solution is to move outside and stay away from groups of 10 or more but winter is coming and we cannot continue to have classes outside or eat dinner in the cold rain, even in Napa.

Schools are reopening and teachers and parents are focusing on social distancing and face masks. Poor inside school air quality could impact test scores and learning significantly. A June report estimated that 41% of the nation’s school districts need major upgrades into the ventilation systems. https://www. businessinsider.com/poor-indoorair-quality-could-make-schoolscoronavirus-hotspots-2020-9

At the same time, commerce is highly dependent on human oneon-one and high-density interactions. For today’s businesses, the single most important investment is retrofitting their HVAC systems to purify the circulating air, sometimes with UV rays and other high-tech solutions. Our residences are less sophisticated.

I checked with Stephen Likens, CEA Energy Expert, on how

Dreamstime

to best retrofit homes and commercial spaces. Here are some suggestions including industry recommendations for all users. https://www.businessinsider. com/poor-indoor-air-qualitycould-make-schools-coronavirushotspots-2020-9

INCREASE OUTSIDE AIR

Open windows and doors; use window AC units with outside air-intakes to bring in more outside air, but only when temperatures allow.

CHANGE OUT FILTERS REGULARLY

Common filters are designed to catch big particles. Look for MERV and HEPA filters, the higher numbers. https://www. ashrae.org/technical-resources/ filtration-disinfection MERVs are good for pollen and small particles. Look into AAF Flanders Nested Glass EZ-green Filters. Check the manufacturer of your system for filter ratings. https:// www.aafintl.com/en/commercial/ browse-products

CHANGE-OUT YOUR HVAC

Heat recovery ventilation systems work between two different temperature sources to reduce residual exhaust heat. Fresh air is improved before it enters the room . https://en.wikipedia.org/ wiki/Heat_recovery_ventilation

INCREASE GRILL SIZES

To maximize airflow, consider increasing floor, wall and/or ceiling grills and duct connections.

ADD HRV/ERV FANS

Whole house fans filter indoor air without losing the required conditioning.

KEEP HOUSEHOLD FANS ON

Local bathroom and kitchen fans if they exhaust to outside and remove contaminants can increase the overall air ventilation

CONSIDER USING A PORTABLE AIR CLEANER/PURIFIER

They can help reduce airborne contaminants, but they haven’t proven sufficient to protect people from COVID-19. Good for allergies and poor air quality. https://www.epa.gov/coronavirus/ indoor

The bottom line is strong airflow without effective filtration or ventilation will not protect. One crucial factor is airflow: the amount of new air that flows through a room or building. Most buildings should have at least 15 CF/M, cubic feet per minute.

Architects and contractors are used to California’s tough Title 24 energy requirements. Last year filtration effectiveness was upgraded by 50% for new construction, but that won’t help those of us under earlier guidelines. Get a good mechanical contractor to look at your systems. It’s worth it.

Chris D. Craiker, AIA/NCARB, is a Napa architect with Craiker Architects & Planners. He has been designing sustainable buildings for more than 40 years.