CLICK Find authors Ed and Carly Wansing on the SOLAR TODAY blog: solartoday.org/blog
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 ener-
gy usage. The new washer’s more efficient spin
cycle means that clothes require less time to
dry on the clothesline. We replaced our refrig-
erator 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 sys-
tem, 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 (lightwave
solarelectric.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 modern-
izations. We installed a dual-flush toilet, which
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 bar-
rels to two 250-gallon water tanks to harvest
more rainwater for our expanded vegetable gar-
den. 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.
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
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. ST