I always look at the bathroom ventilation when I'm staying in hotels. Last month I was at the Air Barrier Association conference in Baltimore and took the photo below. Can you tell anything about what might be happening by looking at it? I didn't do a thorough investigation, but here's what I see.Read More
Energy Vanguard Blog
I know it's not air conditioning season, but this story is too good to wait until summer rolls around. My friends at E3 Innovate in Nashville — you may remember them for finding the home ventilated with dead possum odors — have done it again. This time they've discovered a crawl space with an unhealthy innovation. Let's take a look at the photos.Read More
Unvented combustion appliances were added to the scope of ASHRAE's residential ventilation and IAQ standard (Std. 62.2) recently. The committee has begun their deliberations on the issue, and at ASHRAE's winter meeting in Orlando this month, the unvented gas appliance industry folks attempted a defense of their products. Based on the results they presented and the reaction from most committee members, I'd say they failed.Read More
It's been a little crackly around here lately. We're having a cold spell in Atlanta, with high temperatures right around the freezing point. As a result, the indoor relative humidity has dropped and we're getting some static electricity. Even better, what I call the Southern Lights are visible at night, too. (I've never called it that before, but hey, a man named Allison is entitled to make things up on the spot.) That's when the microfiber blanket on the bed lights up every time I move.Read More
If you have an attached garage where you live, the odds are high that your indoor air quality is worse than a home without an attached garage. Just take a look at the photo below to see some of the sources of pollutants that can get into your home's air. How many do you see?Read More
The British newspaper The Guardian recently published an article on asthma and energy efficient homes, claiming that reducing energy use in homes can hurt indoor air quality (IAQ). But wait! Asthma may not be the only thing to fear with energy efficient homes. A researcher whose report is cited says that poor IAQ also can lead to "lung cancer, chronic obstructive pulmonary disease, airborne respiratory infections and cardiovascular disease." Should we be worried? Are those airtight houses going to kill us?Read More
My friends up in Maine came up with the concept of the Pretty Good House a few years ago, and I love the idea! Not everyone can or wants to build a LEED Platinum, Living Building Challenge, Passive House. But a lot of architects, builders, and homebuyers would like to design, build, and live in houses that are better than the barely-legal, code-minimum houses that populate the market. The Pretty Good House, then, is the way to go.Read More
Psychrometrics, you may recall, is the science that involves the properties of moist air and the processes in which the temperature or the water vapor content or both are changed. To understand how all that works, we need quantities and we need them to be well-defined. Some are easy to understand (e.g., dry bulb temperature and barometric pressure); others are a bit more abstract (e.g., enthalpy). Here we'll take a look at the main psychrometric quanitites, define them carefully, and tell which commonly used term you should avoid.
I have a confession to make: I've fallen in love with psychrometrics! After water itself, moist air has got to be the most interesting substance in building science. And the psychrometric chart, in all its many manifestations and with its multitudinous quantities, is a thing of beauty. Well, at least it is to me, and maybe it will be to you, too, after you get to know it a bit better.
Insulation is good. More insulation is better (although at some point, more may not be cost effective). It reduces the amount of heat a home loses in winter or gains in summer. You can get there by building thicker walls and putting more insulation in the cavities, or you can put insulation on the outside of the structure, as in the Perfect Wall. The photo below shows thick insulation in the cavities of a home with double-wall construction.