We recently completed our net-zero farmhouse project. The house has a contemporary design and feel, but the exterior pays tribute to the classic farmhouse designs found throughout the Shenandoah Valley.

Some highlights of the project:

- 0.46 ACH50 final blower door test
- Exterior mineral wool insulation (Roxul Rockboard 80)
- Fiber cement siding (HardiePlank) and double-locked standing seam roof
- 5.6 kW PV system, with islandable capability
- Hearthstone Craftsbury woodstove with outside air intake
- Fujitsu slim duct high efficiency heat pumps
- Renewaire EV90P Energy Recovery Ventilator

This project combined energy efficiency with resilient design. Genesis Home and Energy installed an islandable PV system (discussed in a previous blog). Key electrical circuits will be maintained during a power outage: lighting, wall outlets, well pump, refrigerator and freezer, microwave, etc.

Although we were somewhat hesitant to install a woodstove in a tight house, the client wanted the ability to heat with locally harvested wood (ambiance, resiliency, radiant heat for comfort). No woodstove is airtight, so there were some risks:

- Backdrafting
- Depressurization of the house
- Lower indoor air quality

We mitigated these risks by making the house all-electric, and eliminating exhaust appliances. The range hood is recirculating. The dryer is a condensing, ventless model. We were also careful about specifying a woodstove with an outside air kit--and positioning the inlet and chimney to provide excellent draft.

John Semmelhack of Think Little fame completed several tests to determine if the woodstove would negatively affect the house. He found that the woodstove had a negligible effect on the house pressure (within the noise of precision). This measurement held when the woodstove was cold AND when it was operating.  He determined that the stove pulled between 10 - 15 CFM (cubic feet / minute) when operating. With the outside air intake the majority of that air is supplied from the exterior.

Promethean Homes, LLC is now a Builder Member of EarthCraft Virginia! Visit their website to learn more information about their green building programs.

www.earthcraftvirginia.org

Although some parents still use alphabet soup it to help their toddlers learn letters and spelling, it is not as popular as it was years ago. I wonder if it because adults are getting a heavy dose of alphabet soup everytime they read a newspaper or magazine or online blog? If you are like me, you are overwhelmed by the sheer number of acronyms you encounter.

Although acronyms are supposed to make it easier to learn a new set of words, I think we are starting to suffer from acronymical confusion.

Some of these acronyms have been with us a long time, or they have been popularized through various media. I'm quite sure you are familar with the YMCA. You may even be a member. And I have little doubt that you know about the CIA, EPA, and FBI. However, you are probably not familar with the growing number of "green building organizations" and standards that have sprouted in the last twenty years. 

In this blog I will provide a brief overview of several popular green building standards. You should note that these programs are in a process of continual revision; what is true today may not hold for tomorrow.


LEED (Leadership in Energy and Environmental Design)

Organization: USGBC (U.S. Green Building Council)

Summary: Perhaps the most recognized green building standard, LEED is a comprehensive standard that covers just about every aspect of construction. It is a sliding scale system. Although you must meet a certain number of points to earn the certification, there are several levels: silver, gold, and platinum. Although it emcompasses both residential and commercial construction, its primary focus is multi-family and commercial projects.

Pros: It covers a broad range of issues, from location efficiency and pollution reduction, to stormwater management and regional material use. It even has a category for bird collision deterrence.

Cons: Critics argue that it fails to adequately address energy efficiency, or that it has encouraged "glass box" architecture. Unsubstantiated energy efficiency claims was even the topic of a $100M class action lawsuit (dismissed in court). The level of documentation required makes this standard cumbersome and expensive for residential projects.


ENERGY STAR

Organization: EPA (Environmental Protection Agency)

Summary: A program of the U.S. federal government, this program focuses on reducing energy use in homes. Certified projects must pass either a prescriptive path or a performance path.

Pros: The name is widely known for its association with energy efficient appliances, and has solid branding because of consumer recognition.

Cons: In years past, critics said that the program lacked any teeth, that it was too easy to meet the standard (performance monitoring of certified houses showed marginal savings). A recent update, Version 3.0, is more rigorous.


EARTHCRAFT

Organization: Southface Energy Institute

Summary: This standard focuses on reducing the consumption of resources, energy, AND water. It applies to new homes, multi-family housing projects, and light commercial construction. Certified projects must pass a number of criteria and tests. The organization says that Earthcraft houses are projected to save 30% compared to code-built houses.

Pros: This standard covers a number of issues, and it does so without adding a lot of complexity to the building or certification process. It focuses on issues that are specific to the Southeastern part of the U.S. It has the backing of the U.S. Department of Energy, as well as the Environmental Protection Agency.

Cons: This standard does not address all aspects of sustainable construction. Also, it is only available in the following states: VA, NC, SC, TN, GA, and AL.


PASSIVE HOUSE

Organization: PHIUS (Passive House Institute US)

Summary: An offshoot of the German based Passivhaus concept, this standard focuses mainly on reducing heating and cooling loads (although overall energy consumption must also meet a strict limit). Certified consultants must model the project using a complex spreadsheet, then test for certain criteria.

Pros: It is one of the most rigorous standards for energy efficiency. Savings are projected to range from 60-70% compared to code built houses.

Cons: The standard only addresses energy consumption. It ignores other issues related to green building. Critics argue that the standard lacks any feedback on cost efficiency, and that it is excessive for some parts of the country.


Other standards include:

LIVING BUILDING CHALLENGE
Organization: ILFI (International Living Future Institute)

ICC-700 NATIONAL GREEN BUILDING STANDARD
Organization: NAHB (National Association of Home Builders)

Regional programs are available too. Literally, there are dozens of local green building programs. Some localities are requiring builders to rate new houses using the RESNET developed HERS Index:

Stuffed yet? Suffering from information overload? Sick of alphabet soup? Me too. All of these organization and standards are giving momentum to good ideas, but they are sometimes difficult to digest.

With our society's level of sophistication, it is hard to image that this will ever become a simple topic, or that organizations will stop using acronyms. So I'll leave you with one more: KISS (Keep It Simple Silly). For designers and builders of high performance homes, the KISS principle still applies.

--------------------------
 
*We have Franklin Delano Roosevelt to thank for being the first to prepare a linquistic feast of acronyms. Back in the '30s, when FDR rolled out the New Deal, reporters struggled to deal with the huge number of new government agencies formed by this legislation. Sarcastic observers started calling them the alphabet soup agencies. Today, these agencies are quickly becoming TNTC (Too Numerous To Count ;)