TechPractices are outstanding housing projects throughout the U.S. where innovative technologies are implemented. Builders and remodelers can use these examples as models for projects of their own.
|The Bentley Residence Snapshot
||Steamboat Springs, Colorado
||Habitat Design Construction
||3,000 sf single-family home
||This house is priced about mid-range of the market. However, the annual energy cost of the Bentley Residence is about 87% lower than conventionally constructed houses.
||I-joist super-insulated walls; natural, low-toxic, recycled and re-manufactured materials; air-tight drywall construction; heat recovery ventilation; solar water heaters for radiant floor heating; rain/grey water harvesting; photovoltaic panels; subsoil irrigation.
This 3,000 sf custom home is for a client who desires to showcase resource efficiency and recycled materials. Materials are chosen for their durability, low toxicity, and recycled content. A system was created to harvest rain and collect grey water for sub soil outdoor irrigation. The heating load is reduced by increasing the efficiency of the building envelope; heat recovery ventilation and passive and active solar heating systems; and high efficiency back-up space and domestic hot water heating systems. The electric load is cut in half by using photovoltaic panels.
Steamboat Springs is at an altitude of 7,000 feet. It has 9,523 heating degree days and an average of 73% of possible sunshine
annually. As a result of super insulation, air-tight drywall, and heat recovery ventilation used on this project, the projected design heating load is 25,000 BTU/hr at a design temperature of -25°F.
A majority of this heating load is supplied through passive and active solar heating systems. South-facing windows admit low winter sun and window quilts at night increase window R-values from R-4 to R-9. A self-pumping three panel solar water heater supplies hot water for radiant-slab floor heating system and for domestic hot water. For back-up, a 94% efficient 100,000 BTU natural gas hot water heater is used for space heating and an instantaneous natural gas water heater supplies domestic hot water. In order to be as self-sufficient as possible, the house uses a photovoltaic solar electric system. Twelve PV panels installed on a seasonally adjustable pole next to the house meet 50% of the annual electric
needs. This is achieved in part through the use of high efficiency lighting products and home appliances. Water efficiency is enhanced with water saving fixtures, appliances, and landscape irrigation equipment. Xeriscaping with native plants eliminates the need for outdoor irrigation for a majority of the site. Rain water from the roof and from around the foundation is collected along with grey water from showers, sinks, and tubs and stored in 500-gallon below-ground holding tank. It is then filtered, re-pressurized, and piped to underground emitters that irrigate the small turf and garden area.
A number of durable, natural, low toxic, and recycled materials are used. The foundation has Styrofoam drainboard with a fabric filter paper. Rain water around the foundation percolates through the fabric filter to the drainboard where it is collected for rain/grey water reuse system.
Dry-blown cellulose with netting insulates walls and ceilings. Cellulose is a non-toxic recycled product with a higher R-value and a much higher resistance to air movement than fiberglass batt insulation.
The floors, walls, and ceilings are framed with engineered wood made from wood scraps. The exterior decking is constructed of "plastic wood," a product made from recycled plastic milk jugs. Special attention should be given to expansion and contraction of "plastic wood" products.
The exterior of the Bentley House is finished with fiber cement siding. An "air-tight drywall technique" inside employs neoprene gasketing installed around all edges, seams, windows, and doors, as well as air-tight electrical switches and outlet boxes.
Other products of note include: carpeting made from 100% recycled plastic soda bottles, natural linoleum, and floor tile made from recycled automobile windshields.
Before window trim and baseboard was installed, the builder performed a blower door test to identify and seal any remaining air leaks.
The available technologies used dramatically lower the house's water and energy use. Although never monitored, the builder indicates that the annual utility energy costs are in the $100 to $200 range. For comparison, the average annual utility cost for a similarly sized conventionally built house is approximately $1,600.00.
Because I-joists were used for wall construction, a special engineering report was requested by the local building code official. No testing was required, but the report had to be signed and sealed by a professional engineer.
The rain water and grey water collection system was originally intended to supply water to toilets, the clothes washer, and outdoor irrigation systems. The code only allows the rain/grey water to be used for outdoor irrigation with subsoil emitters.
The builder says that there are pros and cons to using I-joists for wall construction. Although I-joists are easy to work with and create extremely straight walls, they are expensive. Other less costly products can be used to achieve similar results.
The builder also indicates how important it is to keep the customer's expectation real when using photovoltaic (PV) systems. Even though electric loads are minimized in this house, PV's supply only half the power. The other half is supplied by the local utility.
Do you have a specific question? Try the contacts listed below:
Habitat Design and Construction Co.
1500 Skyview Lane, Suite A
Steamboat Springs, CO 80487
James Hardie & Coy Pty Limited
26300 La Alameda, Suite 250
Mission Viejo, CA 92691
Fiber-Cement Products, Inc.
Excelsior Industrial Park
P.O. Box 99
Blandon, PA 19510-0099
610-936-5533 or 888-9FC-PINC
iLevel™ by Weyerhaeuser (formerly Trus-Joist MacMillan)
33663 Weyerhaeuser Way South
Federal Way, WA 98003
APA, The Engineered Wood Association
P.O. Box 11700
Tacoma, WA 98411-0700
Plastic Lumber Trade Association
540 South Main Street
Akron, OH 44311-1023
Image Industries, Inc.
P.O. Box 5555
Armuchee, GA 30105
EPA EnergySTAR Appliance Program
Mailbox 6202 J
Washington, DC 20460
Consortium for Energy Efficiency
1 State Street Suite1400
Boston, MA 02109
Association of Home Appliance Manufacturers
20 N. Wacker Drive Suite 1231
Chicago, IL 60606
American Nursery & Landscape Association
1250 I Street NW, Suite 500
Washington, DC 20005
American Horticultural Society
7931 East Boulevard Drive
Alexandria, VA 22308
American Water Works Association
1401 New York Ave NW, Suite 640
Washington, DC 20005
Plumbing Manufacturers Institute (PMI)
800 Roosevelt Road Building C, Suite 20
Glen Ellyn, IL 60137