Building Science

Solving Comfort Problems Caused by Attic Kneewalls

Posted on August 21, 2013 by Allison A. Bailes III, PhD, GBA Advisor

In Texas, they call them “hot walls.” My friend Mike Barcik likes to say they’re what separate you from the blast furnace. Down here in the warmer climate zones, where attics get up to 8,000°F (well, that may be a slight exaggeration), many people call them a liability. (Sadly, architects haven't gotten the message.)

A Stupid — and Illegal — Way to Air Condition Your Garage

Posted on August 14, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Sometimes people do the craziest things. Take that photo at right, for example. That's a new home being built in Austin, Texas. The arrows point to three air conditioning ducts. In the garage. Yes, they're air conditioning the garage.

ASHRAE 62.2 Committee Chair Defends Ventilation Standard

Posted on August 7, 2013 by Allison A. Bailes III, PhD, GBA Advisor

The great ventilation debate of 2013 roars on. Last month, I wrote about Building Science Corporation's residential ventilation standard for new homes, to be released officially at Building Science Summer Camp this week, and then followed that up with an interview with Dr. Joseph Lstiburek.

An Interview with Dr. Joseph Lstiburek

Posted on July 31, 2013 by Allison A. Bailes III, PhD, GBA Advisor

Dr. Joe Lstiburek of Building Science Corporation is on a mission. The issue is residential ventilation. He contends that the residential ventilation standard, ASHRAE 62.2A standard for residential mechanical ventilation systems established by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Among other requirements, the standard requires a home to have a mechanical ventilation system capable of ventilating at a rate of 1 cfm for every 100 square feet of occupiable space plus 7.5 cfm per occupant., ventilates at too high a rate, causing problems with humidity in hot or mixed humid climates, comfort and dryness in cold climates, and too much energy use everywhere. The 2013 version makes it worse.

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.

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