Many homeowners want to install a solar electric system but don’t know if their roof gets enough sunshine. The return on investment from the solar panels and the positive environmental benefits are highly dependent on the energy production.
Here’s the essential information to determine if a house has ample solar potential.
Solar energy systems generate the most electricity when the panels are pointed south. If the orientation of the roof is slightly off from due south, it won’t have a dramatic impact on the total energy production.
If the solar panels face east, they will generate more energy in the morning. Conversely, if the panels face west, the system will have excellent afternoon production but little in the morning. It is not recommended to install panels on a north-facing roof (in the northern hemisphere).
To determine the energy loss due to orientation, go to the PVWatts website and edit the azimuth field.
Shade from Trees and Buildings
Although trees are wonderful, they can have a negative impact on solar production. Buildings and trees located east, west, and especially south can hinder electricity output. The most crucial window is the mid-day hours, between 9 am and 3 pm. Thus, obstructions on the south side of the home can have the biggest impact. If trees are an issue, trimming certain branches might be highly beneficial.
Evergreen trees can have the biggest impact on solar panels because they create shading throughout the year. Deciduous trees tend to not have leaves when the sun is lower in the sky during the cold weather months. When planting new trees, select shorter varieties or plant them on the north side of the home.
Chimneys, Skylights, and Dormers
Unfortunately, most houses do not have simple, rectangular roofs. Too many limitations may decrease the size of the solar system, making it more challenging to be net-zero. Skylights, chimneys, and vent pipes can reduce the available space for the array. Likewise, dormers and gables can shade panels, decreasing output. Thankfully, it is possible to break up the array into several sections.
Although orientation and shading have a bigger influence on electricity production, a roof with a steep pitch or angle will generate more during the winter months than it would if the panels were flat. The ideal pitch depends on the latitude of the property. Further north, a steeper angle is better for total production throughout the year. Closer to the equator, a smaller angle is preferable.
Alternate Solar Panels Placement
In some cases, detached roofs, awnings, carports, and even trellises can be excellent locations for a solar array. Roofs are often the top choice because they keep the cost of the installation down by using existing infrastructure. Adding an awning or ground-mounted system adds to the installation cost if new materials are used to support the PV panels.
Many solar installation companies will conduct a shade analysis of a property. Reputable contractors will give an honest assessment, but others may sugarcoat the findings. Another approach is to look at the roof every hour to determine how much of the time it’s sunny. It is helpful to do this several times throughout the year because the sun is at a different angle in the summer and winter.