Musings of an Energy Nerd

Drainwater Heat Recovery Can Lower Your HERS Score

Posted on November 4, 2016 by Martin Holladay

Drainwater heat recovery (DHR) devices have been around for more than twenty years. By now, over 60,000 of the units have been installed in North America. When one of these devices is installed in a typical single-family home, it can reduce the amount of energy used for domestic hot water by 15% to 22%.

States are Amending, then Adopting, the 2015 IECC

Posted on October 28, 2016 by Martin Holladay

In the U.S., the system for writing, adopting, and enforcing building codes is peculiar. Lots of people are confused about building codes.

Anyone interested in understanding building codes in the U.S. needs to start by learning a few basic facts:

  • The U.S. doesn’t have a national building code. Building codes vary from state to state, and in some cases from city to city.

Ventilation Failures and Vocabulary Lessons

Posted on October 21, 2016 by Martin Holladay

During the last week of September, I attended the annual conference sponsored by the Energy and Environmental Building Alliance (EEBA). This year’s conference was held in Frisco, Texas.

EEBA was founded in Minnesota in 1982; the original name of the organization was the Energy Efficient Building Association. Thirty-four years later, EEBA is still going strong.

A Superinsulated House from 1984

Posted on October 14, 2016 by Martin Holladay

Were the techniques of superinsulation well understood in the early 1980s? The answer depends on who you talk to. Back then, in most areas of the country, residential builders were slapping together leaky homes insulated with thin fiberglass batts. Yet even 35 years ago, a small subset of builders had already adopted superinsulation techniques. In the early 1980s, anyone who was interested in the topic had access to in-depth information on superinsulation details.

Rural Construction Methods in Tropical Countries

Posted on October 7, 2016 by Martin Holladay

Green building enthusiasts come in two camps. Builders in the first camp follow programs that emphasize energy efficiency; those in the other camp are so-called “natural builders” who emphasize the use of materials like straw, mud, and sticks. (For an analysis of this split, see Low-Road Buildings Are Homeowner-Friendly.)

Zehnder Develops a Ductless ERV

Posted on September 30, 2016 by Martin Holladay

Anyone who lives in a tight house needs a ventilation system. Unfortunately, most ventilation systems are expensive. If you decide to install a high-quality heat-recovery ventilator (HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. ) or energy-recovery ventilator (ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV.) with dedicated ductwork, your ventilation system might cost you between $6,000 and $8,000.

Adopting a Green Lifestyle

Posted on September 23, 2016 by Martin Holladay

I’ve always struggled with the word “green.” I’m not quite sure what “green building” means, but most definitions include the idea of environmental responsibility.

To get a better handle on environmental responsibility, it might be useful to create a list of green values or aims. Here’s my stab at creating such a list.

Green values include:

  • Avoiding actions that injure biodiversity.
  • Avoiding actions that destroy important habitat, especially habit for threatened species.
  • Avoiding actions that increase the likelihood of species extinction.

Indoor Microbes and Human Health

Posted on September 16, 2016 by Martin Holladay

The word “health” is usually reserved for living things. Our children can be healthy or unhealthy, and so can our pets and the apple trees in the back yard. But what’s a “healthy house”?

Most people use the phrase “healthy house” to describe a house that either promotes the health of the occupants or, at a minimum, doesn’t make the occupants sick. Of course, everybody wants a healthy house: Who wants to live in a house that makes you sick?

A Web-Based Information Resource From the DOE

Posted on September 9, 2016 by Martin Holladay

The Building America program, a branch of the U.S. Department of Energy, funds research on ways to improve the energy performance of new and existing homes and provides advice to new home builders and home-performance contractors. In recent decades, Building America has provided millions of dollars of research grants to energy consulting companies, including the Building Science Corporation, Consol, Florida Solar Energy Center, IBACOS, Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Institute U.S., and Steven Winter Associates.

Being a Carpenter Isn’t Simple Anymore

Posted on September 2, 2016 by Martin Holladay

After working for years as a carpenter, Bart Laemmel, a resident of Crested Butte, Colorado, decided to upgrade his skills. “I have a thirst for knowledge,” he said. Speaking at a presentation at the recent Westford Symposium on Building Science, Laemmel deployed his self-deprecating humor. “I am 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,” he said. “It was an intense training — seven days straight. I figured I knew everything. And I am a LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. professional. I know how to check stuff off.”

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