At Your Holiday Party, Ventilate Like Your Life Depends On It

Perhaps we’ll never agree on masks, vaccines and lockdowns, but can we please agree that a ventilated home is the safest way to gather this year?

I’m not going to spend much time laying out the situation. We’re facing a “tripledemic” of flu, new variants of Covid-19 that evade vaccinations and medical treatments, plus respiratory illness, at the same time we’re gathering with friends and family and traveling in close-packed vehicles.

The chances of a sudden return to mask protocols is slim to none, given the politicization of the issue, and hospitals are nearing capacity, so what’s to be done? We can go with the flow, accept an untold number of deaths, and sort through the sorrows later, as potentially millions of long-term, life-threatening health issues arise from a viral disease we barely understand? Or we can turn on the bath fans and range hoods, and reduce our risk.

I’m oversimplifying somewhat, of course, but the concept of diffusion applies to most airborne respiratory diseases. Reduce the viral load and lessen the chance of infection. Various standards exist to estimate how much airflow you need to cut transmission rates. For example, the Rhode Island Dept of Health prescribes 4 to 6 air changes per hour for school classrooms. Hospitals tend to have higher standards.

This figure is a baseline for diffusion only--meaning introducing fresh air and exhausting contaminated air to keep air moving. Recirculating air is not advised, unless the space has a high efficiency filtration system, such as MERV16 or HEPA filters. 

A Party Less Perilous

Let’s say you’re planning a big family dinner of 10-20 people, with few if any masks, no pre-testing for Covid-19, and some sniffly noses among the kids.

Aside from trying to keep some physical distance, pulling aside one person to talk on the porch for an hour, or going outside “to play with the kids,” your best hope to avoid infection  is ventilation.

Let me preface this advice, however, by noting that if you do choose to party like it’s 2017, even if you’re vaccinated, you’re still walking into a health minefield. You’re choosing to use only one defense to protect yourself from a pervasive enemy. But you’re going in with a better chance of coming out without a life-threatening illness.

In an ideal situation, you would crank up a heat recovery or energy recovery ventilator to swap out air in the house without wasting as much energy.

If you don’t yet own an ERV or HRV, however, you can start ventilating immediately by turning on your bathroom exhaust fans.  Bath fans are supposed to change the air in the shower room at about 15 ACH to remove steam. If you leave the bathroom door ajar and run the fan continuously, you can “pull” air from nearby rooms to some degree. Crack a window open half an inch in another room and feel the breeze.

To get even more air moving, however, look to your kitchen range hood. Yes, yes, they’re often noisy—but so are hospital ICUs—so just suppress your yearning for quiet and turn the fan on. Tape the button on if you have to, so that some drunken sister-in-law doesn’t shut it off as 10 people crowd around the kitchen, talking too loudly with no masks.

Range hoods typically have settings of 300 cfm or more, much higher than the 50-100 cfm found in baths. With some selective slightly open windows in other parts of the house, the range hood can act like a whole house fan, dragging fresh air through much of your living space.

Plan Your Drafts

With freezing weather in the forecast, you’ll want to plan the “intake” points for fresh air wisely. Otherwise you’ll have guests going around behind you closing doors and windows. 

Keep in mind that most heating systems don’t bring in any fresh air. They recirculate the air already inside the home. Plan to spend a little more to preheat the home warmer than usual before the party, so guests can feel comfortable despite the life-preserving drafts created by the fans.

If your home lacks bath fans, or has an all-but-useless recirculating range hood fan, you can always go old school, and put fans in windows and leave other windows open. It will be mighty chilly, but if your guests have to wear ugly holiday sweaters to stay warm, that’s a small price to pay for a greatly elevated level of protection from severe illness.

If you’d like to dig deeper into how ventilation reduces the risk of viral infection, here’s a detailed article I wrote explaining various types of filtration and ventilation methods that can help reduce your covid exposure.

I wish you all the best, in the safest possible home environment.