Shade Issues No Problem for This Solar System
July 28, 2016
By Mike Kluk
Richard and Linda Allison, their three daughters, and Linda’s mother live in a house on a quiet South Davis cul de sac. With six in the family, power use is going to be relatively high no matter how you cut it.
Their power bill was averaging about $400 per month. When it hit $750 one hot summer month, they knew they needed to find a way to stop the bleed. But it wasn’t just the bills that posed a problem: the Allison family’s roof wasn’t fully exposed to sunlight throughout the day.
High energy bills made solar attractive
“Our ever increasing PG&E bill motivated us to try rooftop solar. We tried to conserve generally and wait until night-time with lower rates to use the washer and drier and other appliances. But that was not conducive to our lifestyle,” said Richard. “So we asked why not look at solar power. We don’t want to waste power, but we do want to be able to use it when we need it.”
Family chose a contractor they trusted from past work
In November of 2015, the Allison family had a 4 kilowatt system put into place. The Allisons received quotes from three different companies and chose Sierra Pacific Home and Comfort.
They were persuaded by the overall cost, the warranty, the ongoing monitoring process offered, and the solar panel brand. They were happy with a solar pool heating system Sierra Pacific had previously installed for them.
Payback in five years, $40K home value increase
The cost of the system was $26,733. With a 30% federal tax credit, the out of pocket expense was $18,713. They decided that buying the system outright rather than financing it or renting made the most sense for them. The system came with a 25 year parts and labor warranty.
Since the installation, the Allisons’ electric bills have decreased by 50 to 75% and they estimate that payback could occur in as little as five years. This example shows how the benefit of solar panels can be greater for people who use relatively more power, largely because it helps them drop to a less expensive tier in the PG&E rate structure.
As an added bonus, the Allisons found that the system added about $40,000 to the value of their home – not that they are planning to sell any time soon.
Shady site produces power via optimizing system
The Allisons’ system is a few panels shy of what they wanted because one section of the roof was consistently shaded by a Davis street tree on a neighbor’s lot that could not be pruned back any further. Since mature trees benefit the environment and Davis’s overall quality of life in many ways, residents looking to install solar will sometimes need to make compromises
Other areas of the roof were not as consistently shaded, but shaded enough to adversely affect production. In this case, Sierra Pacific solved the problem by installing an “optimizer” to each of their LG brand panels. Optimizers are devices that can turn an individual panel off, removing it from the system if it becomes shaded and stops producing allowing the others to continue to produce at peak efficiency. Optimizers cost a bit more, but provide a solution when shade is an issue.
Panels that are wired together might all be shut down partially or totally when shadows fall over just one.
The Allison’s panels are also installed on three sides of their home, showing that while a south facing roof is ideal for solar, panels can be mounted to face other directions and still work.
Their pool heating system does not require the same degree of direct sunlight to operate, so it is mounted on roof areas that are less than ideal for solar electric.
The Allisons now take advantage of the huge plus of clean power as well as the cooling comfort of large neighborhood shade trees.
Ten out of ten
The Allisons’ system is monitored at a basic level for free by SolarEdge, the manufacturer of the optimizers and inverter. Through the SolarEdge portal, the Allisons can also remotely access daily information about the productivity and status of their system. SolarEdge evaluates and, if necessary, will repair the system if there is an unexplained reduction in power production.
Overall, the family rates the experience with the contractor and satisfaction with their new solar power system as a ten out of ten.
Energy saving appliances and measures came first
The Allisons are not new to saving energy. Over the years they installed dual pane windows in their home, switched to energy efficient light bulbs, installed ceiling fans, an on demand water heater, and a solar pool heating system. Plus, they drive a hybrid automobile.
All of these changes and additions have allowed the Allisons to save money, enhance their comfort and quality of life, and benefit the environment. Rooftop solar eliminated the Allisons’ monthly bill shock and turned it into a “made in the shade” win-win situation.
Richard and Linda Allison live with their family in the Rose Creek neighborhood of South Davis.
Cool Davis is a coalition of citizens, the City of Davis, and community organizations working to empower our community to reduce greenhouse gas emissions.