58 | March 2020
I
'm writing this part of BAD ASS HVAC as the COVID-19
coronavirus is shutting things down here in the U.S.
Flights to Europe were just suspended. Classes at
many universities are moving to 100% remote access.
The stock market is plummeting. Many school districts
nationwide are closing for several weeks. "Social dis-
tance" is the buzzword now, all in hopes of slowing the
spread of this disease, so fewer of us can be at risk and we
can prevent the collapse of the healthcare system, which
sadly has happened in Italy.
While covering our mouths when coughing, washing
hands often, avoiding touching of the face, cleaning surfac-
es frequently, and refraining from large gatherings seem to
be the biggest factors in slowing the spread of the virus, it
strikes me that the HVAC systems in our homes could use
a lot more attention as a preventative measure.
This chart from ASHRAE (The American Society of
Heating, Refrigerating and Air-Conditioning Engineers)
shows how important humidity is for a number of health fac-
tors. Note how keeping relative humidity between 30-60%
reduces the propagation of both viruses and bacteria.
A historical note: we've seen something like this before.
The Spanish Flu of 1918-1919 drastically changed how
boilers were sized. Instead of being sized to heat a home
under normal conditions, they were sized to heat a home
in winter with the windows open. The idea was that fresh
air and sunlight would reduce the spread of the virus. As
important as humidity control seems to be, that much dry
cold air is probably not advisable, but some fresh air seems
like a safe bet. This article will focus on fresh air and its re-
lationship to indoor air quality.
Hopefully you've heard this from me before; we breathe
3000 gallons of air per day. Since we spend 90% or more
of our time indoors, most of that air goes through an HVAC
system. Without overselling the benefits, there are a few
ways HVAC can help reduce viral spread:
By Nate Adams
HVAC and the Coronavirus
