March 28th, 2009
If you’re one of those folks out there who is suffering from a bit of carbon fatigue, then a post in the NY Times’ Green Inc. blog this week could either provide additional motivation for green projects or increased fear of another jargon-laden debate. Green Inc highlighted the growing trend of striving for “water neutrality”, as highlighted at the Fifth World Water Forum in Istanbul last week.
The idea is gaining ground within a group of companies looking to understand and reduce their consumption of water, including Coca Cola, whose chairman has pledged to eventually balance out all of the water used in its products and manufacturing processes through conservation elsewhere (over 80 billion gallons worth!).
This got me to thinking: what would it take to be water-neutral in our own homes, meaning that we don’t import any net water? If we include all of the water that goes into our food and the products we consume, then it gets ugly real fast (see this post on the water content of food, for example). But what about our direct water use - showers, irrigation, toilets, etc?
Now, this would require some significant changes to a home and to local building/health/safety codes, since the only way to go water-neutral is to reuse graywater and harvest/store rainwater. Both of these options now face numerous permitting and legal obstacles around the country (including some pretty counterintuitive ones, like Utah and Colorado bans on capturing ANY rainwater at your home). Assuming we could, though, how much rain would it take to provide a family’s annual water needs?
After some pretty simple calculations, it turns out that the home of a typical family of three could be water-neutral in climates receiving roughly 25″ of rainfall or more per year under the following assumptions:
- Three-person household;
- Rainwater captured, stored and reused;
- Graywater system used;
- Indoor water efficiency measures employed: low-flow showerheads, toilets, faucets and appliances;
- Outdoor water efficiency measures employed: smart irrigation control, rain shutoff, soil moisture sensors, climate-compatible landscaping.
This basically means that home water neutrality is feasible if you live in the Midwest, anywhere along the US Atlantic or Gulf Coasts, in the Northwest and in higher rainfall areas of the West and Mountain West (here’s a set of maps to review for your area). The detailed calculations are shown below. You can use our Environmental Impact Calculator to make similar calculations for your home and region.
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March 13th, 2009
Our journeys through the green modular landscape often take us to the big cities of America. That’s not surprising, for that’s where you find the high densities of green architects / builders, green consumers and manufacturing plants that really make a prefab company sing. Recently, though, we came across a prefab company from rural West Virginia that will give any of its urban counterparts a real run for their money: Eco Structures, out of Maidsville, West Virginia.
Eco Structures is the brainchild of John Garlow, who has been building timber frame homes and using structural insulated panels (SIPS) out of his own workshop since the late 1970s. Several years ago, when it became clear that the green prefab housing market was ripe for liftoff, he decided to put his many years of prefabrication expertise to use with a new “green” twist. He designed and built a prototype modular Eco Structure on his own property and a new company was born.
The Eco Structure homes are targeted for LEED Platinum certification by the USGBC (process under way), and they come in 450 square foot modules that can be assembled in various configurations according to a client’s needs. Some of the more innovative elements of the Eco Structure system:
- Passive Solar and Ventilation Design. Almost all of the home’s heating, cooling and hot water is provided via smart use of passive solar design. The south side is primarily glass, and awnings and decks provide shade in the summer but allow sunlight in during the winter. Exterior air is drawn in through large pipes buried in the ground, which warms it in the winter and cools it in the summer.
- High Efficiency Building Envelope. The home’s exterior walls and roof are all made out of SIPS that attain insulation levels of R-36 to R-46 and meet the latest in energy codes across the country. Windows are all quad-paned - energy-efficient dual-pane windows are combined to surround a layer of inert gas, offering maximum efficiency.
- Rainwater Harvesting and Water Efficiency. In John’s prototype, rainwater is filtered to drinking water standards and stored in a 2,400 gallon cistern. The system provides nearly 100% of the home’s fresh water demand. The prototype also employs graywater recycling and composting toilets (although these might not be to code in all jurisdictions).
- Advanced Home Automation System. A home automation system made by Home Automation, Inc. controls all of the energy, security, smoke detection and home entertainment systems in the house, and can be configured and monitored over the Internet.
- Solar Thermal and Radiant Heating System. Water is heated via two separate solar thermal systems (one on the roof, one embedded in a vertical wall) and then stored in an in-home tank. Hot water goes to both fixtures and an in-floor radiant heating system. In the prototype, the radiant system is also connected to a backup wood-fired boiler.
(Click here for more information on other green building components and systems.)
Clearly, some of these elements aren’t appropriate for all settings. Each base module can be configured with any of the various options above, depending on client needs and local permitting standards. The 450 square foot modules are easy to transport, so Eco Structures can serve most of the Eastern and Southern US. And, they are compatible with pier foundation systems, so you don’t necessarily need a crane to move them into place. The target price (confirmed in the prototype) for an Eco Structure home is approximately $150 - $175 per square foot.
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