The Inadequacy of House Burping - GreenBuildingAdvisor

Some years ago in a previous century, I spent the month of January in Germany. It happened to be a winter of extreme cold, with a low temperature of –40°^† at one point. And yet my German companions liked to keep a bedroom window open each night. I was young and hardy then, but it makes me shiver to think of it now. I don’t recall if they called it lüften, but it was certainly akin to that practice. The current misguided fad here in the U.S. calls it “house burping,” a name intended mainly to grab the ever-diminishing attention of social media addicts. Now airing out a house can be a good thing, but let’s talk about why you should be wary of this craze.

Indoor air quality is more than ventilation

I’ve been hammering away at this for a few years now. Ventilation is only one part of a good IAQ strategy. In my IAQ online course, I cover seven steps to good indoor air quality. You can get the gist of what I cover from an article I wrote in this blog. Ventilation isn’t even the best thing you can do to improve IAQ.

If you really want a good way to breathe healthier air, do source control first and then add some high-efficiency filtration. Those two address a lot of the most important indoor air pollutants. Yes, ventilation is definitely important, but opening your windows three times a day regardless of the current indoor and outdoor conditions is foolish. You might as well follow a herd of lemmings over the cliff—or believe that lemmings actually do that.

Outdoor air quality matters

Are you going to open your windows for “fresh air” when wildfire smoke has engulfed your home? I hope not. But what about a less extreme case? Let’s say the outdoor ozone level is high, or PM2.5, the fine particles that make it deep into your lungs, then your bloodstream, and on to the brain or the heart.

Opening the windows when the outdoor air quality is bad only makes things worse.

Comfort problems arise

Recently here in Atlanta we had a low of –9°C (15°F) and a high of 2°C (35°F). Which three times that day should I have opened the windows? None! I don’t like to freeze inside my own house. Plus, my heat pump is sized perfectly to meet our design heating load, which occurs at –5°C (23°F). It would never have caught up with all that cold air coming in.

On a hot, humid day in summer, it’s equally as bad. The air conditioner wouldn’t be able to handle the extra humidity load. The house would be sticky and uncomfortable most of the time. No one wants that.

Humidity gets worse

In winter, cold air is dry air. If you live in a home that has a lot of air leakage, you most likely already have low indoor humidity without opening the windows. Opening the windows not only makes it colder indoors—it also makes it drier. If you like to burp your leaky house, I hope you like 5% to 10% relative humidity—and dry, itchy skin, static electricity shocks, and desiccated nasal passages.

I mentioned in the last section the summer humidity problem. You don’t want that either. I monitor the outdoor temperature and dew point to determine if opening the windows is a good idea or not. If the outdoor temperature is moderate and the dew point below 15°C (60°F), I open the windows. Otherwise, they stay closed.

Energy gets wasted

A lot of house-burping critics have already covered this one. Releasing all that expensive air that you’ve paid good money to heat, cool, filter, humidify, or dehumidify is just plain blockheaded. And now it’s more true than ever since utilities are raising rates for homeowners so they can subsidize the cost of energy for data centers. I know the bills for my all-electric home have gone up significantly in the past two years.

What you should do instead of house burping

You want clean air in your home, of course. Who doesn’t? House burping isn’t the solution. Do as much as you can in the seven-step approach to good IAQ and you’ll get a lot of the benefits—or more—without the drawbacks of house burping. And when you add ventilation, do it with a balanced ventilation system that has heat and moisture recovery. That’s an energy-recovery ventilator (ERV); it’s what I have in my house.

If you want to find out more about ventilation, here’s a perfect opportunity for you. Two weeks ago I gave a talk on this topic at the HVAC Symposium in Florida. They recorded the presentations, and you can get a virtual ticket and watch them all for the low price of $29. There are much better options for good IAQ than house burping.

^†If you know your Fahrenheit and Celsius temperature scales, you know that I don’t need to give the unit here.  The two scales are equal at –40°.

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Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia.  He has a doctorate in physics and is the author of a bestselling book on building science.  He also writes the Energy Vanguard Blog.  For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel.