Building Science

Grow Your Own Green ... Insulation, That Is

Posted on July 24, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Rather than blowing agents, this insulation uses growing agents. It's natural. It's made with agricultural waste and fungi. You can grow it in place. No hydrocarbons are involved, and it yields little to no toxic waste. Compared to most other insulation materials, it takes little energy to make the stuff (low embodied energyEnergy that goes into making a product; includes energy required for growth, extraction, and transportation of the raw material as well as manufacture, packaging, and transportation of the finished product. Embodied energy is often used to measure ecological cost.). Indoor air quality is likely to be better, too.

Wow! If you're looking for a super green insulation, mushroom insulation could be for you... if you can wait a bit longer.

EPA Warns Against Unapproved Refrigerants in Air Conditioners

Posted on July 17, 2013 by Allison A. Bailes III, PhD, GBA Advisor

"A New Zealand technician got fire balled in the face," a member of the HVAC-talk.com forum stated bluntly. He was referring to a case in New Zealand where an HVAC tech got burned when he thought he was working on a system with R-22 refregerant, which is not flammable, but which instead was filled with propane, which is flammable.

Resistance May NOT Be Futile in the Residential Ventilation Wars

Posted on July 10, 2013 by Allison A. Bailes III, PhD, GBA Advisor

“ASHRAE 62 is the only national consensus standard document there is. Follow 62.2. Resistance is futile.” So said Dr. Max Sherman last summer in a presentation for the Building America Technical Update meeting. (Download pdf official report here.) That statement about resistance being futile isn’t generally a line you want pinned to you if you’re trying to win hearts and minds, but I asked Sherman about it.

Insulated Rooflines and Shingle Temperatures

Posted on July 3, 2013 by Allison A. Bailes III, PhD, GBA Advisor

One of the most common questions I get when I describe homes with insulated rooflines is, "What does that do to the shingles?" Some roofing companies have made noise about this topic, saying that if the shingles can't conduct heat downward into the attic, the shingle lifetime will be greatly reduced.

An Epidemic of Duct Disease and Enclosure Problems

Posted on June 26, 2013 by Allison A. Bailes III, PhD, GBA Advisor

When an air conditioner breaks down in hot weather, homeowners reach for their phone. The HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. company then sends someone out to the home with the immediate goal of getting the AC running again so the occupants will cool off. The thing is, though, that most homes have problems that run deeper than the cause of the broken air conditioner.

Is NIST Serious About Net-Zero-Energy Homes?

Posted on June 19, 2013 by Allison A. Bailes III, PhD, GBA Advisor

The National Institute of Standards and Technology (NIST) still handles a lot of our basic numbers work, keeping lasers, hunks of metal, and atomic clocks that determine our standards of length, mass, and time. But it turns out they also have an interest in net-zero-energy (NZE) homes.

They’ve built and outfitted an amazing NZE research facility, and they also have convened meetings of experts to develop guidelines for NZE homes. But there’s something about their latest report I just don’t understand.

Taking a 20-Year-Old Florida House to Net Zero

Posted on June 12, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Steve Larson, a builder and home energy rater in Florida, sent me an e-mail with his energy bills for February through July of 2012. When you subtract out the monthly service charges, he paid only $5.35 for electricity during those six months. That's right — less than a dollar a month for electricty... and then $9.88 a month for the service charge.

A 3-Ton Air Conditioner Will Rarely Give You 3 Tons of Cooling

Posted on June 5, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Today I'm going to give you three reasons why your 3 ton air conditioner isn't really a 3 ton air conditioner. Of course, there are more than three reasons, starting with the fact that it's not 3 tons in weight. That unit refers to cooling capacity and harkens back to the days of ice.

Why Do We Measure Air Conditioner Capacity in Tons?

Posted on May 29, 2013 by Allison A. Bailes III, PhD, GBA Advisor

A few years ago, a HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. rater student in a class I taught told a funny story. He was an HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. contractor and said he was installing a new air conditioner for an elderly woman. As he was explaining things to her, he mentioned that they would be installing a 4-ton unit. "Oh, my," she said. "How are you going to get something so big into my back yard?"

Does a Composting Toilet Stink Up Your House?

Posted on May 22, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Ten years ago I was building a green home. It had passive solar features, was built out of structural insulated panels, sent all the greywater out to the back yard to water fruit trees, and was going to be super energy efficient. One feature above all others, though, captured people’s attention when I described the house to them — the composting toilet.

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