How Does Humidity in the Home Affect Viruses?

Indoor air quality is a huge issue in 2020. People stayed inside far more than usual for the first half of the year, and as the weather gets warmer, things are only becoming more uncertain.

Science points to a decline in the spread of viruses during the warmer months. High humidity has a lot to do with that.

But, research – and history- also predict a possible surge when it gets cold again.

Liberty Bond Parade

That photo’s from the infamous 1918 parade in Philadelphia that ignited a second wave of the Spanish flu. The story’s gotten a lot of traction this year, but it’s worth reading when thinking about how you’ll prepare your home for the summer and winter.

That’s not to sound alarmist at all. But, it’s a reminder that there’s information out there to help us deal with the health concerns we’re facing today. And, it’s worth knowing about the benefits of indoor air quality and how to stay healthy.

So, in this article, we’re focusing on how humidity affects viruses, and what you can do in your home to reduce the spread of any virus – pandemic or otherwise.

We’ll look at that potential drop in infections in the summer — and what role humidity plays in those numbers.

Of course, we’re not pathologists. But, we do know HVAC. And, when you’re talking about air purification and controlling the humidity in your home, well, that’s in our wheelhouse.

We’ll walk you through using your HVAC system to help keep you healthy.

Meanwhile, you can check out information on what relative and absolute humidity mean here and how they affect your home and health in general.

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What Happens to Viruses in High Humidity?

The good news is that a normal amount of humidity — between 40 to 60 percent humidity — reduces the spread of viruses. But, it doesn’t prevent it completely. And, when the humidity gets too high, you run into problems again.

So, not much of an answer? Well, let’s break this down a little further.

How Humidity Affects Viruses

Viruses are sensitive to humidity, although the jury’s still out on why that is, exactly. But, when the ambient humidity is upwards of 30 or 40 percent, the virus particles become inactivated and don’t travel as far.

To get into the weeds a little: When relative humidity is at 23 percent or less, up to 77 percent of virus particles remain infectious. Up the relative percentage to 43 percent, and the number of infections particles drops to 14 percent.

So, keeping your levels above 40 percent deactivates most viruses. That means if they’re present, or if someone coughs or sneezes, you’re much less likely to catch it.

That said, however, too much humidity causes other problems.

Problems With High Humidity

Before you let your home start feeling like the rain forest, know that you’ll run into other health problems when the humidity gets too high.
People who suffer from allergies, asthma, or other respiratory ailments often experience trouble breathing if there’s too much moisture in the air. Besides feeling stuffy, all sorts of airborne contaminants — pollen, dust, and more — will hang in the air instead of falling to the ground.

Then, it’s easy to inhale them and have an existing problem flare up. It may not be a virus, but it can still be dangerous enough for a person not to have trouble breathing.

Now, let’s say that person is infectious. If they start coughing due to another issue, they’re still spreading viral particles — adding to what’s already in the area.

Do I Need a Dehumidifer All Year?

Humidity and Ventilation

Simply increasing moisture in the air isn’t a magic bullet. You have to consider other factors — and a big one is ventilation.

What It Means When Your AC Short Cycles

Go back to our stats: Even at optimal levels, there’s still a small percentage of viral particles remaining active. And remember: That’s not a fixed number, but a portion of the total. The more particles you have, the more still-infectious viral particles are present.

That’s why it’s tougher to catch these outdoors: No particles, be they dust, pollen or other pollutants, stay in any one place very long. Instead, they blow around.

The same applies to when you have your windows open and the fan blowing: Dirt, viruses, allergens, and other stuff can blow right back out of your house.

It’s why you can end up with sick building syndrome when your office building has windows that don’t open. Or, when you close your windows for the summer and run the air all the time.

In those situations, you lose ventilation, and all sorts of contaminants begin building up.

Controlling Humidity at Home

So, the object here is not to only increase your humidity at home, but to control it. You want it between 40 and 60 percent all the time, no matter how hot or cold it is outside.

Your first step is getting a humidistat. It measures the humidity, just like a thermostat tracks the temperature.

The Temperature Will Fluctuate

Next, invest in humidifiers and dehumidifiers if you need them. Odds are you will have to dehumidify your home in the summer, especially if you are not using an air conditioner.

Then, in the winter, you may have to add some moisture to the air. The problem then is that cold air is naturally dryer than warm air. Then, heat through a forced-air system is a dry heat. Put together that makes the moisture levels unnaturally low.

Finally, you can also invest in an air purifier. It won’t affect moisture, but it will filter out many of the particles that you’re trying to get rid of in the first place.

It all sounds like a lot, but it doesn’t have to be. You have the choice of buying off-the-shelf units for each of these. It won’t cost all that much, but you’ll have to stay on top of them all — turning them on and off, moving them from room to room, and measuring the humidity levels.

The other option is to have your HVAC company install higher-grade appliances that treat your entire home. Whole-home humidifiers, dehumidifiers, and AprilAire purifiers hook up directly to your central heating and cooling system.

It costs more, but you make up for it in comfort and convenience. First of all, these will work better than any room-level appliances because they affect your entire home’s air circulation.

Second, you don’t have to worry about monitoring them. Just hook them up, and they’ll do the work on their own, just like your furnace or central air.

Depending on your home’s needs, you may not need all three of these. So, your best bet is to start with a consultation with an HVAC company.

Based in Havertown, PA John Cipollone has worked with homes in Delaware and Montgomery counties for more than 50 years. As a trusted member of the community, we can help you keep your home —- and yourself — healthy all year. Email or call us today for a virtual or in-person consultation.

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