Build small, smart, and invest in the sun
By Rick
Talk is cheap, but building is not. Some of you have asked me to stop talking about building small and show an example of a small, sustainable home. Fair enough.
Our firm recently completed a design for a regional Habitat for Humanity house. The challenge: Can our communities have sustainable homes that are also affordable to build?
We call our response the S.A.V.E. (Solar-Assisted/Volunteer-Erected) House. It was specifically designed for a Western NY climate, for a typical 40’ x 100’ city/village lot, for up to 3 bedrooms. It’s only 1000 square feet, not including three distinct outdoor “rooms” – a generous front porch, back covered patio, and a driveway that doubles as a pergola-shaded dining area.
Through careful design, the S.A.V.E. House reduces fossil fuel demands by 60-80% over a conventional home, encourages outdoor living, basks in natural light and provides inspiring yet compact living spaces. The key to unlocking the Finger Lake Region’s solar heating potential is what we call the Tall Wall system, made out of off-the-shelf components.
On the home’s south side, 250 sf of double wall polycarbonate panels concentrate the sun’s rays into a high, narrow sunspace insulated from the house. Absorber plates mounted inside the sunspace send hot water to an insulated tank, ready for cloudy day heating duty. Sunny days also create convection currents to directly warm the house. When the sun doesn’t shine, the convection dampers close and the insulated wall prevents heat loss.
Here are other ways the S.A.V.E House saves:
SAVE on HEATING
- Convection. Sunny day convection heat loop through sunspace wall.
- Radiation. Sunny day direct gain heat from south glass.
- Thermal mass. Concrete floor spreads heat gain over 24 hours.
- Heat Transfer. Sunspace absorber plates transfer heat to storage tank.
- Hydronic. Cloudy day/night-time in-floor heating distributes efficiently.
- Reduced load. 1000 sf of heated space reduces demand.
- Reduced loss. In-track insulated curtain seals south glass against loss.
SAVE on DOMESTIC HOT WATER
- Extract heat from wastewater. Incoming water is pre-heated by outgoing wastewater from shower, dishwasher and laundry.
- Extract heat from solar storage. Heat exchange coils in solar-heated tank further boosts temperature.
SAVE on WATER USAGE
- Graywater. Drainwater is used for flushing toilets.
- Rainwater. Cistern collects rain for carwashing and gardening.
SAVE RESOURCES
- Build Small. Compact plan minimizes material consumption.
- Build Modular. South wall module minimizes material waste.
- Build pre-fab. Small-dimension truss construction reduces waste.
SAVE MONEY
- Reduce bills. Payback time for sunspace components is 5 years.
- Reduce material costs. 1000 sf plan frees up money to invest in “green” strategies.
- Reduce unpredictability. Decreased reliance on fluctuating fossil fuels increases family’s financial stability.
SAVE NEIGHBORHOODS
- Encourage outdoor living. Three distinct outdoor “rooms” provide opportunities for community engagement.
- Respect Solar Access. Roof angle permits southern sun to reach neighboring homes.
- Catalyze green innovation. An accessible, affordable, “demonstration” project in the neighborhood proves the efficacy of green principles.
These are readily-built, modest-cost, low-tech approaches to infill housing in our region. We can start by building small and smart, and investing in the sun.