Energy Vanguard Blog

Air Conditioner Sizing Rules of Thumb Must Die

Posted by Allison Bailes on Fri, Aug 26, 2016

We design a lot of heating and air conditioning systems at Energy Vanguard. Alexander Bell, who goes by Andy, is our design wizard, and I've been getting involved with the process again lately. When I talk to potential clients, a lot of them tell me their contractor wants to size their air conditioner using a rule of thumb. The rule is usually something like this: Install one ton of air conditioning capacity for every 500 (or 600) square feet of conditioned floor area. How far off are they? Let's take a look.

Read More

Tags: comfort, heating & cooling

The Evolution of Passive House in North America

Posted by Allison Bailes on Fri, Jul 1, 2016

In 2002, Katrin Klingenberg introduced the passivhaus program to North America when she built the Smith House in Urbana, Illinois. She had come to the US from Germany, where she studied architecture and got involved with passivhaus. But is this really where it all began?

Read More

Tags: design, comfort, environment & sustainability

MAD AIR:  Duct Systems, Infiltration, & Their Interactions

Posted by Allison Bailes on Thu, Jun 30, 2016

A lot of discoveries and research work over the past four decades have led to our current understanding of air leakage in buildings. I’ll mention a few here, but I want to focus on one: the MAD AIR paper by John Tooley and Neil Moyer. The full title of the paper was, Mechanical Air Distribution And Interacting Relationships. The first letters of those words spell out MAD AIR.

Read More

Tags: heating & cooling distribution, air leakage, comfort, indoor air quality

A Sticky Psychrometric Situation: Wet Bulb Temperature

Posted by Allison Bailes on Tue, Jul 7, 2015

Wet bulb temperature tells you how easy it is for water to evaporate. Sounds simple enough, right? Today I'll give you a couple of examples to see how well you really understand that simple statement. First, early last month my friend Mike MacFarland texted me about the day he wore his wet bulb shirt on a mountain bike ride. Here's what he said:

Read More

Tags: comfort, environment & sustainability, moisture problems, health & safety

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:

Read More

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

A Beautiful Solar Home in Utah Nears Net Zero Energy Use

Posted by Allison Bailes on Wed, Mar 18, 2015

I'm writing this on St. Patrick's Day so let me tell you a wee bit about the O'Mearas. Kevin and Svetlana O'Meara live in a beautiful home in Utah that's oh-so-close to being a net zero energy home. After I wrote about how home building is like skiing two years ago, Kevin invited me out to see their home and this year I managed to do so. My wife and I visited them for two days last week and Kevin told me all about the house, including his one major regret.

Read More

Tags: ENERGY STAR, design, heating & cooling distribution, insulation, air leakage, energy code, energy conservation, comfort, windows, environment & sustainability, solar energy, water heating, ventilation, heating & cooling, green building

A Net Zero Energy Home in a Beautiful Green Community

Posted by Allison Bailes on Tue, Nov 26, 2013

I spoke at Serenbe, a beautiful green community southwest of Atlanta, this weekend and got a chance to visit a net zero energy home while there. Built by Luis Imery, one of the home energy raters we're a HERS provider for, the home has garnered quite a bit of recognition. In fact, they recently picked up a pretty big award from Southface.

Read More

Tags: ENERGY STAR, HVAC, building enclosure, heating & cooling distribution, insulation, air leakage, energy code, comfort, spray foam, indoor air quality, solar energy, ventilation

Fixing an Old House? Follow Einstein's Advice

Posted by Allison Bailes on Mon, Nov 4, 2013

I get a lot of questions from people asking how they should go about fixing their homes. Sometimes it's specific (What's the best way to insulate my kneewalls?), and sometimes it's a hands up in the air, With all these problems, where do I start?  I'll focus on the latter today and let Albert Einstein provide the guidance you need.

Read More

Tags: HVAC, building enclosure, crawl space, air leakage, attic, comfort, windows, indoor air quality, diagnostic/performance testing, solar energy, water heating, health & safety, ventilation

This Little Ventilation Mistake Can Lead to Comfort Problems

Posted by Allison Bailes on Wed, Oct 9, 2013

If you're designing a ventilation system, first you have to determine how much air the house needs. You can use ASHRAE 62.2 or the new BSC-01 for that task. Then you have to decide what type of ventilation system to use: positive pressure, negative pressure, or balanced. In many green homes, the balanced system is becoming a popular choice. I've seen some installations lately, though, that are missing a key component.

Read More

Tags: HVAC, design, heating & cooling distribution, comfort, ventilation

Why Do So Many Expensive Homes Get Walmart-Class HVAC Systems?

Posted by Allison Bailes on Tue, Oct 8, 2013

The fellow standing in the home he's having built is proud. It's his dream home in Brookline, Massachusetts after all. The Wall Street Journal last week published an article about affluent home buyers getting their own jumbo construction loans to do just as Mr. Deshpande has done. Usually, they hire a home builder to build the home, but if you look at that photo, you'll see a mistake that's common even in million dollar homes.

Read More

Tags: HVAC, design, heating & cooling distribution, comfort, spray foam