By Nate Adams
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 distance” 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 surfaces 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 factors. 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 relationship 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:
- Tightly controlling relative humidity levels between 30-50%.
- Below 40F outdoor temps we recommend staying between 30-40% to reduce the risk of condensation on cold building surfaces. If you see condensation inside your windows, you can reduce humidifier settings or open a window until it clears. At higher indoor humidity levels, when it’s colder than 40°F outside, there may be condensation happening somewhere you can’t see, which can cause other problems.
- During warmer winter weather, 40-50% is advised, also to reduce condensation. We talked about dehumidification in part 2: next time we’ll talk about humidification.
- Humidity control seems to be the most important function with regards to HVAC and viral spread.
- It’s quite easy to track humidity, this data logger is only $20 and pairs to your phone, I highly recommend having at least one.
- If you use a humidifier, try to use distilled or reverse osmosis water to prevent putting things other than water into the air.
- Filtering as much bad stuff out of the air as possible (including viruses and bacteria) using MERV 11 or greater filters (discussed in part 1). MERV 13 or higher is needed for viruses.
- Adding outdoor air to dilute indoor pollutant levels – which we’ll discuss this time.
These are all things that BAD ASS HVAC does.
Humans Suck at Long Term Thinking – Plant a Seed Now
While we all have coronavirus on our minds right now, that’s really only one piece of creating healthy home environments. A good HVAC system also helps with reducing particulate pollution, chemical pollutants, mold, dust mites, asthma, and much more.
The downside to this is that adding all the capabilities that BAD ASS HVAC offers is only easily possible (and cost effective) at equipment replacement time.
We humans excel at dealing with a clear and present danger, as we’re seeing with the response to COVID 19, but that’s going to be temporary. In a few months or years, our memories will be fading about it. As humans, we suck at dealing with things that have a long time horizon, such as investing for retirement, health effects of excess weight, or in this case spending a little extra on a new HVAC system for it to include BAD ASS capabilities.
Before we dig in, you might mentally plant a seed to ask for a BAD ASS system when you buy new HVAC, so the next time there might be a wildfire or pandemic you’ll already have such a system in place. Should these threats arise, all you will need to do is turn up the HVAC’s fan speed to increase filtration and fresh air, and then adjust humidity settings.
OK, enough about coronavirus, let’s get to talking about fresh air, the 4th function of HVAC!
Read the full article in the March 2020 issue of Healthy Indoors Magazine at: https://hi.healthyindoors.com/i/1227696-hi-march-2020/57