Energy Vanguard Blog

Is Evaporative Cooling the Answer to High Air Conditioning Costs?

Posted by Allison Bailes on Tue, Jun 30, 2015

This time of year, air conditioners are running like mad to keep people cool in their homes. Here in Atlanta, we've had a couple of weeks of hot, muggy weather, with a little break on Sunday. Now we're heading back to the mid-90s with high dew points again. As a result, some people are starting to dread those air conditioning bills arriving and wondering what they can do to save energy. Is the Kickstarter-funded Mistbox the answer?

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Tags: heating & cooling

17 Reasons I Love Working with Buildings

Posted by Allison Bailes on Mon, Jun 29, 2015

Yesterday I had lunch with Robert Bean and Eric Griffin at the ASHRAE conference here in Atlanta. As we talked about how we got into the field of building science, I began thinking of the reasons I love doing what I do. My background is physics, and I really enjoyed teaching it when I was in academia, but I didn't really fit in there. When I discovered building science (and later blogging), I finally found my niche. Here's why:

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Tags: fun, design, education, business, comfort, indoor air quality, environment & sustainability, big picture, creativity, health & safety, blogging

Psychrometrics, Part 2 - The Quantities in the Chart

Posted by Allison Bailes on Tue, Jun 2, 2015

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.

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Tags: moisture problems, ventilation, heating & cooling

How to Clean Out Your Air Conditioner's Condensate Line

Posted by Allison Bailes on Fri, May 29, 2015

Your air conditioner does two jobs: It cools down the air and it dehumidifies the air. If you live in a dry climate, you want the AC to dehumidify as little as possible because it uses extra energy and makes you spend more on lip balm and hand lotion. If you live in a humid climate, you really want it to do that second job as well as it can to keep your indoor air dry and comfortable. But where does all that condensate go?

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Tags: heating & cooling

Psychrometrics - Impenetrable Chart or Path to Understanding?

Posted by Allison Bailes on Tue, May 26, 2015

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.

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Tags: moisture problems, ventilation, heating & cooling

Does the Nest Learning Thermostat Save Energy?

Posted by Allison Bailes on Wed, May 20, 2015

The Nest Learning Thermostat has been on the market for nearly four years now. One of the biggest things the Nest folks use as a selling point is energy savings. "Programs itself. Then pays for itself." That's the first thing you see when you go to the Nest homepage. But what do the data say? Three independent studies plus a whitepaper from Nest provide some answers.

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Tags: heating & cooling

This Lack of Building Enclosure Design Makes Extra Work

Posted by Allison Bailes on Fri, May 15, 2015

Take a look at the photo below. See anything missing? If you don't see it yet, look at the big opening at the bottom right of the photo and you should be able to deduce what that room is. It's a garage. Now look at the framed wall between the garage and where I was standing when I took the picture. You see it, right?

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Tags: design, air leakage

Nest Thermostat Data Unveiled at ACI Conference

Posted by Allison Bailes on Tue, May 12, 2015

The Nest thermostat has been around since October 2011, quietly collecting data on how your home — and the homes of hundreds of thousands of your neighbors — operates. It gathers information about indoor temperature, relative humidity, air conditioner runtime, auxiliary heat operation for heat pumps, and much more. Unlike the Ecobee thermostat, however, Nest doesn't let its owners see all those data (which is a problem only for energy geeks really). Enter Michael Blasnik.

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Tags: conferences, heating & cooling

Why Did the Chicken Go to the ACI Conference?

Posted by Allison Bailes on Mon, May 11, 2015

I love the ACI National Home Performance Conference! This year's conference was spectacular. It was in New Orleans, which is always fun. The stars of home performance were there. The Californians came back. (That's one of them in the chicken costume below. ACI after dark, which even has its own Twitter handle, @ACIafterdark, is fun no matter where the conference is, but wild things can happen in NOLA.) And perhaps best of all, Michael Blasnik revealed data from the Nest thermostat for the first time.

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Tags: conferences

Moisture Transport, Sorption Isotherms, and Aliens Drinking Beer

Posted by Allison Bailes on Tue, May 5, 2015

You know about the fourth state of water. (You read my last article, Introduction to the Physics of Water in Porous Materials, right?) Not liquid, not vapor, and not solid, it has properties similar to liquid water but not quite the same. Today we'll take a look at how that physics affects the transport of water through porous materials.

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Tags: moisture problems