Eric and Donna Mendelson built their home in Missoula in 2008 with energy conservation in mind. The walls are constructed of structural insulated panels (SIPs), and the heating system is a hybrid high-efficiency heat pump and high-efficiency gas furnace. Eric explains that the furnace heats the home when outside temperatures are coldest, and the heat pump takes over when it’s warmer than 28-30 degrees F, maximizing the overall efficiency of the system.
The Mendelsons didn’t include solar in the initial design of their home, but they hoped to add a solar array one day. So they jumped at the chance to learn more about solar at MREA’s Clean Energy Fair in September 2014. At the fair, they attended workshops on solar electricity and financing and incentives, and chatted with several local solar installers. “The fair was very informative,” recalls Eric. “For people like us, who’d had solar panels tucked away in the back of our minds for ‘some day,’ learning that they’re quite available now at a reasonable price really catalyzed us to start moving.”
After the Clean Energy Fair, the Mendelsons began contacting local solar installers, ultimately choosing to work with Solar Plexus. Jody Aldegarie of Solar Plexus recalls that the Mendelsons’ goal was to install a large enough solar array to offset their electricity use, including the electric heat pump. She proposed a 5 kilowatt array.
The biggest design challenge was where on the roof to install the solar panels. The options were the garage roof, which faces south but is shaded by neighbors’ trees, or the house roof, which is less (though still partially) shaded and faces southwest, less optimal for solar than due south. They chose the house roof. Jody explains, “We decided that the uppermost roof of the house was the most appropriate. It was high enough to be mostly out of the trees, shallow enough that its orientation away from south was mitigated and it had the most open square footage to work with.”
Due in part to their concerns about the partial shading of the house roof, the Mendelsons opted to have power optimizers installed at each panel to increase the system’s energy output. The power optimizers also allow the Mendelsons to track the performance of each individual panel from their home computer.
The installation was completed in April 2015. The Mendelsons enjoy tracking the performance of their solar array on their computer, and Eric reports that in its first few weeks it is producing better than anticipated. “It’s fun to watch,” he says, “and we’re looking forward to being able to graph our solar production throughout the year.”