On southern and western exposures canvas awnings minimize solar heat gain in summer cooling months.
By locating the home and office on the same lot, the daily commute has been eliminated. Added to the savings in gasoline is the time gained that can be spent on more productive and fullfilling activities. A downtown location encourages walking and bicycling which has health benefits as well as saving gasoline.
One of the biggest impacts on energy use is the size of the building. Smaller structures use less materials, which saves energy in production, transportation, installation and maintenance. Smaller structures take less energy to heat and cool. The residence here is only 1730 sf. but feels larger due to high ceilings, openings between floors, and a large glass door to the exterior which visually expands the room to include the courtyard. The use of exterior space in our climate also allows for smaller interior spaces.
INDOOR FINISH MATERIALS
Using structural materials as finished materials reduces the products that are manufactured, shipped, maintained and replaced. Here, the Doug Fir roof decking and beams are the finished ceiling; no sheetrock. The walls have a sanded compound finish; no paint. The floors are stained and sealed concrete; no carpet.
Savings will extend into the future as the products that are not initially included will never need maintenance or replacement.
A large sliding glass door in the Great Room combined with the dark stained concrete floor allows for solar gain and storage in the winter. In the summer a large retractable canvas awning keeps the sun out.
Between rebates, tax credits (commercial) and depreciation, the cost of photovoltaics can be reduced to 25–30% of original cost. In this case the energy savings more than paid for the monthly cost to purchase the sytem.
PASSIVE COOLING CEILING FANS
Cassablanca type ceiling fans circulate air in the summer which provides a greater sense of comfort in warmer temperatures. Again, with far less electricity use and corresponding cost than air conditioning.
PASSIVE COOLING NIGHT AIR FAN
When passive cooling via the thermal chimney effect is inadequate, 36" industrial fans bring in large quantities of cool night air. This is technology borrowed from the wine industry. These fans allowed air conditioning to be eliminated. The electricity required to run the fans is a small fraction of the cost to power AC.
PASSIVE COOLING THERMAL CHIMNEY
Openings in the floors create a thermal chimney (hot air rising) that exhausts hot air high in the space and pulls in cooler air from outside. Outside air cools the thermal mass in the structure which then is able to absorb heat the following day keeing temperatures comfortable.
ON DEMAND GAS BOILER
A 98% efficient instant gas boiler heats water for both radiant heating as well as domestic use. Eliminating the tank associated with conventional water heaters means there is no energy wasted in heating stored water.
Concrete slabs at grade and on the upper floors add mass to the interior which absorbs daytime heat in the summer and provides the mass for radiant heating in the winter. Insulation between the slab and exterior stem wall reduce heat loss. Use of 5/8" sheetrock vs. 1/2" adds mass as well.
Windows properly placed reduce the need for electric lighting during daylight hours. In addition to reducing direct energy usage, this lowers the need for cooling in the summer.
LOW MAINTENANCE EXTERIOR MATERIALS
The exterior materials are brick, corrugated steel, rusting cor–ten steel, and Hardipanel siding. Only the siding will ever need maintenance (repainting).
LOW WATTAGE BULBS
The use of fluorescent light fixtures and dimmers significantly reduce the electricity used for lighting.
The use of salvaged materials reduces the need to manufacture new products and saves room in landfills. The front door to the house and garage, and this gate were all salvaged. Use of these types of components can also add charm to a new project.
HIGH PERFORMANCE GLASS
The use of dual glazing, heat blocking films, and inert gasses between the glass panels significantly reduce the summer heat gain.
Hot water is circulated in plastic tubing within the slab to warm the mass of the floor. The mass moderates and stores the heat. Radiant heat provides the same level of comfort with lower air temperatures compared to forced air heating.
The use of plants that are native or have low water needs enabled the use of drip irrigation which conserves water.
Our approach to sustainable design begins with the site. Is it an urban infill location or a large property in the country? How do the solar orientation, topography and prevailing winds interact with access to the site and views? How much involvement does the Client want in operation of the systems? How interested is the Client in long term or life cycle costs as opposed to the initial cost of the project. What is an acceptable payback period for investments in energy saving features? These are questions we ask as we begin the design process. Sustainability is built into the project from its inception, not added on at the end.
We have been doing this kind of design long before the phrases ‘Green Building’ and ‘Global Warming’ became part of our regular vocabulary.
We will highlight our recent 205 Center St. project to illustrate strategies that can be employed in reducing energy use.
205 Center St. is a live/ work project that includes the office of Alan B. Cohen, Architect, his wife’s painting studio, and their residence. Nothing in 205 Center is particularly exotic. Energy savings are realized by making some lifestyle choices, incorporating a few routines into one’s daily life (ie. opening and closing windows), and with the use of ‘off–the–shelf’ components.
Prior to moving into 205 Center we lived in a house and I worked in an office built in the 60’s. Both are similar in size to 205 Center St. The office was in Santa Rosa, CA and just over a 17 mile one way commute from our home in Healdsburg. It is interesting to compare the energy usage before and after 205 Center. Natural gas (space and water heating and cooking), electricity (air conditioning, lights, fans, pumps, appliances, equipment), and gasoline (auto and truck fuel) were converted to BTUs (British Thermal Units) in order to compare overall energy use. We reduced our use by over 70% after moving to 205 Center St. See the attached Comparison of Energy Use for the data.