Going Solar Step by Step
By Ed Wansing, with Carly Wansing
Our solar-powered home rests in what might seem an unlikely location: a developer-built neighborhood in tiny Ashland City, Tenn., just outside of Nashville.
My wife, Carly, and I purchased it in 2004, as recent college grads with new careers and not a whole lot of money. Although the house was just four years old, the previous owner had done little to improve energy efficiency. Historical data revealed that its energy bills were near average for houses in the Southeast.
As newly minted intern architects, we soon discovered how inefficient traditional architecture and construction have become. Eager to help change the way buildings are designed and built, we got involved with the local Middle Tennessee Emerging Green Builders and Middle Tennessee chapters of the U.S. Green Building Council (USGBC). We helped to implement recycling programs in our offices. In short order, peers at Carly’s office christened her Queen of Green. I became known as Mr. Green Jeans at my firm.
At home, we started with small changes, switching out our incandescent light bulbs for compact fluorescent ones and installing a programmable thermostat.
We put up a small clothesline to use when the weather cooperated. A screening of the documentary “Kilowatt Ours,” about the dangers of coal-generated electricity, enticed us to join the Tennessee Valley Authority’s (TVA’s) Green Power Switch program. Each block of green power we purchase for $4 represents 150 kilowatt-hours of renewable energy that the utility pledges to add to its power mix. We also started recycling. Ashland City doesn’t have curbside pickup, so we have to take our recycling to Nashville. We typically fill four 18-gallon recycling bins per month. As a result, our trash has dwindled to less than half a bag weekly.
After a year in our new home, we broke ground on an organic vegetable garden.
We began composting food scraps and lawn and garden waste to create fertilizer for the garden and flowers. The compost has been a most beneficial addition to our heavy clay soils.
We set up rain barrels to reduce the runoff from our house and for use in watering the garden.
In 2006, we moved to fertilizing only with compost or organic fertilizer. Ours is the greenest lawn in the neighborhood, and we like knowing that the compost used to fertilize our vegetables no longer includes the chemicals we once applied to our yard.
To eliminate some of the pollution caused by mowing and to reduce runoff from our property during storms, we’ve planted wildflowers. When we can’t get our vegetables from the garden, we buy organic food, and we carry reusable cloth shopping bags everywhere we go.
Choosing Sustainable Upgrades
When it came time to add a home office in 2006, we decided to locate it in a portion of our unfinished basement. We salvaged some new-looking carpet tiles from an office building that was being renovated and installed them over our unfinished concrete floor. To maintain access to the plumbing and electrical systems, we used corrugated metal in the ceiling. That proved smart when our icemaker line sprung a leak while we were on vacation. We were able to pull the metal off of the basement ceiling, wipe it off, let the subfloor dry and reinstall. The finishing touch to the basement was closing in our stairs, which were the original framed open risers and 2- by 12-inch (5- by 30-cm) steps. We used Dow Wood Stalk, a compressed wheat straw composite board produced with glues containing no added formaldehyde. A low-VOC polyurethane coating gave the new stairs a golden finish.
Remaining space in the basement became our entertainment room. Working in architectural firms, we had access to the cardboard tubes that plotter paper comes on. After collecting quite a few of them, we created a bar by topping 40 tube “towers” with a piece of glass salvaged from a coffee table. Each tower could support an estimated 4,000 pounds, so not only is the bar sustainable, but it’s also sturdy and durable.
Next we focused on reducing our water usage. We started by installing low-flow showerheads and aerators in the bathroom sinks. During the Southeast’s 2006 and 2007 drought, we began recycling our shower and bath water to water our newly planted trees. We also upgraded our five 55-gallon rain barrels to two 250-gallon water tanks to harvest more rainwater for our expanded vegetable garden. When the drought ended, we couldn’t go back to just letting the water go down the drain. Now we use the gray water to flush our toilets. I also built a bigger clothesline, enabling us to line-dry all of our clothes during warm months.
In 2007, we decided to replace our carpet with hardwood floors. We chose bamboo when we could find no Forest Stewardship Council-certified American hardwood in our area. Within months, Carly’s allergies cleared up, and we no longer had to run a humidifier during the winter. The bamboo floors were so nice that we decided to replace carpet in the spare bedrooms with cork flooring. While we were at it, we replaced the sheet vinyl in the kitchen with cork flooring, as well. The cork in the kitchen is pleasantly warm and cushiony to stand on when you’re preparing meals. We like it so much that in our next house, we’ll opt for cork in the master bedroom instead of the bamboo.
Reducing Energy Demand
In 2006, we purchased a Prius for carpooling to work. Our offices were right across the street from one another, so sharing the car was a no-brainer. Carpooling in the Prius helped us do our part to reduce congestion on the roads and reduce our carbon footprint. It also saved us a lot of money in gas and maintenance associated with driving two vehicles. On days when carpooling wasn’t an option, I drove my vegetable oil-fueled Mercedes diesel or my motorcycle, which gets 50-plus miles per gallon.
In 2007, we purchased a frontload washer and dryer, further reducing our water and energy usage. The new washer’s more efficient spin cycle means that clothes require less time to dry on the clothesline. We replaced our refrigerator with the highest-rated Energy Star unit we could find. We also put our electronics on power strips and powered them down when not in use, to eliminate phantom loads. Other than replacing our seldom-used HVAC system, we’d done everything we could think of to reduce our energy usage. Yet we still found ourselves asking, where do we go from here?
We found our answer when Carly’s office, Street Dixon Rick Architecture in Nashville (streetdixonrick.com), installed 72 solar panels on its roof. Steve Johnson with Nashville-based Lightwave Solar Electric (lightwavesolarelectric.com) installed the system. I got in touch with Johnson, who happened to be an acquaintance through USGBC. Johnson gave me some background on photovoltaics (PV) and helped design a system for our house. We selected Evergreen Solar panels for their low carbon footprint in production and reduced prices for blemished panels. We installed 12 180-watt panels for a total installed capacity of 2.16 kilowatts.
Siting the system was tricky because our house faces west instead of south, the optimal placement for solar panels.
To maximize solar access, we elected to install the panels on poles in the side yard. The six-inch galvanized steel poles were set into two holes, each two feet (0.6 m) in diameter and five feet (1.5 m) deep. Each pole was then set in concrete to ensure it could handle the large wind loads the panels would experience.
In December 2007, the completed system was tied to the grid. We were now producing our own clean energy on site! We supplement the system with a 5-watt solar panel used to charge battery packs. The battery packs charge our phones, iPods, rechargeable batteries and even our laptops.
Now that we were producing most of our power, we wanted to conserve enough to enable us to produce all the electricity we used.
In February 2008, we replaced our 80-gallon electric water heater with a gas-fired tankless water heater. That greatly reduced our electrical usage and only slightly raised our gas bill. It dropped our energy usage below the amount the PV system generated in the winter and spring months. But, we wondered, would we be able to produce everything we used when we were running the air conditioning?
That goal led us to install radiant barrier in our attic to reflect radiant heat from the asphalt shingle roof. Lower temperatures in the attic significantly reduced the amount of time the air conditioner had to run to keep the house cool. After the radiant barrier was installed, we blew more recycled fiber cellulose insulation into the attic to further reduce heat transfer through the ceiling.
Last year we slowed down on the modernizations. We installed a dual-flush toilet, which we still flush with gray water from the bathtub. The dual-flush toilet helps to keep our water usage low now that I work from home full time. We also installed high-efficiency ceiling fans in the master bedroom and living room to help maintain airflow.
We’ve done our best to take advantage of passive cooling and heating, as well. In the summer, we use our air conditioner modestly, and if the evening low drops below 70, we open all of the windows to allow the cool air in. In the morning, we close the windows and blinds to retain the cool air. When our air conditioner is running, we set it at 82 while we are out, 78–80 when we are home and 78 at night.
In the winter, we open all of our blinds to allow for maximum passive solar heating, and we set the thermostat to 55 when we’re out, 66–68 when we are home and 58 while we sleep. Moderate HVAC settings are the single-biggest thing most households can do at no cost to reduce their gas and electric bills.
Since February 2008, when our solar panels were first active for an entire billing cycle, we have not paid an electricity bill. Our highest bill was $14 in January 2009, but that amount came out of our rolling credit. As of this February writing, we have a $60 credit. Our utility, TVA, pays us a 12-cent-per-kilowatt-hour premium over the retail rate. For example, if we pay 10 cents a kilowatt-hour, they pay us 22 cents per kilowatt-hour for everything we produce. We have a 10-year contract with TVA guaranteeing this amount.
Getting Neighbors on Board
Looking to the future, our goal is to have a true net-zero-energy home, producing as much energy on an annual basis as we consume. Our home improvements to-do list includes new Serious Materials windows and doors, said to be up to four times more efficient than standard Energy Star windows and doors. We are also considering buying a high-efficiency wood stove for heating.
Many people in the neighborhood have stopped by to ask us about the panels and what we’ve done in our home to earn a credit from the electric company. Others have seen our efforts featured in newspaper articles and television interviews.
It turns out that our Ashland City development, far from an unlikely location, is fertile ground for solar. After seeing the reports, several people have asked me to design PV systems for them.
Photovoltaic System Performance, Ashland City, Tenn.
- Tennessee has an average 208 days of sunshine.
- 2.16-kilowatt system installed in December 2007.
- System produced 2,820 kilowatt-hours (kWh) in 2008, 2,495 kWh in 2009.
- Average monthly household consumption in 2009: 253 kWh (347 kWh in summer months, 239 kWh in winter months).
- Tennessee Valley Authority pays a 12-cent premium over the retail rate for electricity produced by the system.
Ed and Carly Wansing are Leadership in Energy and Environmental Design Accredited Professionals (LEED APs) and associate members of the American Institute of Architects (AIA). Ed (firstname.lastname@example.org) works as a sustainable design consultant with Architectural Energy Corp. (archenergy.com) and is the technical programs coordinator for the Collaborative for High Performance Schools.
He is the Middle Tennessee Emerging Green Builders chairman and the Emerging Green Builders national committee chairman, and he sits on the Middle Tennessee U.S. Green Building Council (USGBC) board of directors. He is pursuing a Master’s of Science in Sustainability at Lipscomb University’s Institute for Sustainable Practice.
An intern architect and project manager at Street Dixon Rick Architecture, Carly (email@example.com) just finished her first LEED Gold project. The Middle Tennessee USGBC recognized Carly with its Green Star Award for individual contribution in 2009.