How to Design for Solar – New Construction Solar Design Concepts
If you are building a new home, garage, or other structure and are considering a solar installation during construction or in the future, there are several solar design features that should be discussed during the design phase. Key solar design features will help optimize a solar array’s performance. Take these items into consideration early on in your new construction project to increase the probability of a successful solar installation, whenever it may occur.
Schematic Solar Design Considerations
Solar design considerations include but are not limited to the following:
Orientation: Orientation is perhaps the most important feature of a good solar design. A roof which faces as close to due south as possible is ideal for capturing the most sunlight and maximizing your system’s electricity output. In some municipalities, there are incentives for arrays that face direction other than south. This is done when a specific location has high grid load during a specific time of day. Orienting panels to generate more power early or late in the day is sometimes done to mitigate load. Check with your installer to see if this could apply to your project.
Pitch: The pitch of your roof can have a significant impact on how much electricity your system produces. Higher pitched (steeper) roofs capture the winter sun better; lower pitched (shallower) roofs favor summer sunlight. The ideal pitch for maximizing a south facing solar array in Rhode Island is 37 degrees. The ideal solar design pitch goes down as the roof orientation shifts east or west of south.
Shading: Ideally, there would be no trees or other tall structures to the south, southeast, or southwest that would cast shade on the solar array. Opt for a shrub or shorter tree species such as a Dogwood tree if you wish to have vegetation on the south side of your house.
Solar Design Development Considerations
Obstructions: Skylights, dormers, chimneys, and vent pipes should be installed on a non-south facing roof if possible. At the very minimum, a good solar design should plan for the location of these items. If they must be on the south side, try planning out where these penetrations might go to minimize shading on the solar array. If you don’t want to plan out the layout, locating these penetrations close to the ridge will maximize space for the solar array.
Roof Type: Asphalt shingles and standing seam metal roofs are the simplest and most cost-effective roof type to install a solar array on. If the roof is standing seam metal a solar array can be installed without penetrating the roof.
Roof Framing: Rafters and trusses with a 2×6 top chord are the simplest for installations. They require fewer roof penetrations, less materials, and less labor for installation. This can save you money on your solar array.
Electrical Solar Design: Be sure to plan on installing the appropriate equipment and leaving enough space for these items; this is discussed further in the construction phase consideration section.
- Ensure the electricity meter on the outside of the house is easily accessible
- If you are considering a Renewable Energy Growth Tariff system, have your on-site electrician install a two-gang meter base
- In addition to a two gang meter base, make sure conduit is in place from inside the house to the meter base for solar wires
- If the array is to be on a different building, be sure that additional conduit is installed in the trench between the buildings when power is being run between the buildings. We recommend putting in a few conduits – PVC is cheap relative to the cost of digging a trench!
Efficiency: When building your home, it is beneficial to incorporate energy efficient building methods into your design to couple with a solar design. Check out this blog from the Newport Solar archives to learn why energy efficiency and solar are better together.
Construction Phase Considerations & Other
Wiring/Access: Be sure to consider pre-wiring your array before the sheetrock gets installed; this allows the wires to be hidden in the walls, rather than run on the outside of the brand new building. If there is a utility room, be sure to work with your installer to find out how much space you should reserve for solar electrical equipment.
Construction Loan: Banks are becoming more receptive to including solar in appraisals and construction loans. Integrating solar at the time of construction can allow you to get the lowest rates possible; wrapping the cost of solar into your 30 year mortgage will give you the best cash flow possible!
Part of the Team: Make the solar installer part of the project team from the beginning; this will help integrate solar design requirements early and avoid rework as the project proceeds.
Use a Local Builder: Local builders tend to have well developed relationships with their sub-contractors, including solar panel installers. This allows them to deliver a well integrated project that meets the solar design criteria. They also have to keep a good reputation in their area; this helps to drive quality construction execution.
Some local builders/architects in RI that we have worked with that work well to integrate solar into their designs:
- Demetrick HouseWrights
- Caldwell & Johnson Builders
- Macht Architects
- MC Squared
- Pike Builders
- Franklin and Company
- Estes Twombley Architects
Use a Local Solar Installer: Local solar installers like Newport Solar, have the relationships and know-how to build your installation to the required design criteria and local code considerations.
Building a new structure is a big undertaking. Investing heavily in all design efforts, building and solar design alike, will help to ensure that an integrated team will carry your project to completion, delivering a building that will meet all of your needs as you live and/or work in your new space.