A Superior Alternative

Net Zero Energy—Concrete Habitat for Humanity Home of the Future

Salt River Materials Group (SRMG) of Scottsdale spearheaded the project introduced at the Greenbuild International Conference & Expo 2009 in Phoenix. Among 200 entries, the Habitat home was selected for the Contemporary Living Desert Tour and features a variety of green technologies.

The Habitat for Humanity® home utilizes HercuWall® instead of conventional wood-frame construction. By combining HercuWall® with conditioned attic space using spray foam insulation directly underneath the roof deck, and energy- efficient windows and HVAC equipment, this home has the essential elements to reach the coveted “Net Zero” energy designation. Exceeding Energy Star certification, the project’s additional “green” products contributed t an overall LEED® for Homes “Platinum” designation, meeting the highest U.S. standards. Eighty out of 126 points are required for Platinum certification and the Habitat home scored a massive 114.5.

Before considering the contribution of the solar system, heating and cooling costs for this home were guaranteed not to exceed $32 per monthby Environments For Living® (MASCO). TheHERS Index Score was finalized at negative four (-4). This is better than net-zero and dep\nding on the family’s energy usage habits, power could actually be put back on the grid. This projec proves that highly energy efficient construction is practical even for entry level housing.

What is a HERS Rating?

A home energy rating involves an analysis of a home’s construction plans and onsite inspections. Based on the home’s plans, the Home Energy Rater uses an energy efficiency software package to perform an energy analysis of the home’s design. This analysis yields a projected, pre-construction HERS Index. Upon completion of the plan review, the rater will work with the builder to identify the energy efficiency improvements needed to ensure the house will meet the specified performance guidelines. The rater then conducts onsite inspections, typically including a blower door test (to test the leakiness of the house) and a duct test (to test the leakiness of the ducts). Results of these tests, along with inputs derived from the plan review, are used to generate the HERS Index score for the home.

The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.

Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.
Source: www.energystar.gov

The HercuWall® Net Zero Method

The building envelope provides the barrier between the interior conditioned space and outdoor environment. Its elements determine a building's energy requirements based on the climate where it is located. These elements include the walls, roof, floor, windows and doors. A properly executed, energy efficient building envelope is the most cost effective method of maximizing the overall efficiency of a building structure and will continue to reduce energy usage and costs for the lifetime of the structure. The high performance wall system chosen is one of the most important components of the building envelope.

Two primary issues need to be addressed in the design and construction of an energy efficient home: insulation and infiltration. HercuWall®, combined with an air resistive insulation barrier in the attic and energy efficient windows and doors, directly addresses these issues.

A HercuWall® home requires a smaller capacity air conditioning and heating system and will cost much less to heat and cool year after year. Because the envelope is so efficient, a much smaller solar system is required to attain net-zero (if that is the goal). Additional benefits include a quieter, more comfortable home that is cleaner and easier to maintain. All of this at a cost comparable to conventional construction.

HercuWall® Is The New Standard

HercuWall® technology meets the requirements of production builders with industry experts recognizing HercuWall® as the first concrete wall solution to do so. HercuWall® does not require highly skilled installation crews. HercuWall® comes to the building site in the form of a kit consisting of numbered panels manufactured according to the building plans with pre-built corners and window and door panels with openings blocked out and in place.

Panels are manufactured to the height of the wall. Multiple stories can be stacked. Crews simply set up the numbered panels in the correct order, tie the system together with top and bottom channels, place rebar into the integral hooks and guides, and then fill the system with concrete. After the concrete has cured, the window and door block-outs are removed revealing straight, accurate, and clean openings.

HercuWall® is The Lowest Cost - Fastest to Install - Highest Performing name brand preengineered reinforced concrete wall construction system available today. HercuWall® provides significant savings in both labor and concrete costs as well as construction timelines, yielding a high quality, high strength, long lasting, energy efficient structure. Website: HercuWall.com