If you travel with a hygrometer, as any seasoned traveler should, what I have to show you here is nothing new. But if instead you've never measured the relative humidity in a hotel room, I've got something interesting for you…
Let’s talk about the controversial issue of venting an unconditioned attic with outdoor air. It's easy to confuse causes and symptoms sometimes, and that happens a lot with attic ventilation. I'll say upfront, though, that the International Residential Code requires…
In a recent article on the result of my radon test, I referred to the US EPA's work on the health effects of radon. They claim that about 21,000 people in the US each year get lung cancer from indoor…
For the past couple of years, I've carried my Aranet4 carbon dioxide monitor* with me when I travel. For much longer than that, I've been checking the ventilation in hotel rooms. What I've found is that it's rare to see…
When you turn on an exhaust fan, it blows air from inside the house to the outdoors. That air leaving the house will be matched by an equal amount of air coming in from outside. The more airtight the house…
OK, it's time to spell this out in black and white because there seems to be some confusion. Monitoring carbon dioxide (CO2), as I've been doing with my Aranet4 portable CO2 monitor* for the past couple of years, is a…
Tis the season for pumpkin spice. It began with pumpkin pie and then later spread to fancy coffee drinks. Starbucks introduced the pumpkin spice latte in 2003 and turned it into a trend. Now everyone knows it even by its…
Since the beginning of the pandemic in 2020, indoor air quality has become a subject of great concern. IAQ and infectious disease scientists discovered early on that COVID is airborne. That means removing virus-laden particles from the air or deactivating…
The past 2.5 years of the COVID pandemic have put a big spotlight on indoor air quality and the spread of infectious disease. I've been writing about various aspects of indoor air quality since I started this blog in 2010,…
Humidity control is becoming a bigger deal than it used to be. As Joseph Lstiburek, PhD, PE said to me one time, "the gap between stupid and hurt is narrowing." Building codes and best practices are getting better, which is…