Solar for New Homes: How to Plan Ahead

                 There are a multitude of challenges facing the owner, architect, and general contractor when planning and designing a new home. Due to the evolution of solar technology and its recent explosion in popularity, many architects and contractors do not have experience with approaching the challenges associated with planning a solar system into the construction of a new home. Roof-mounted solar has been available for decades, but solar systems are still primarily installed on homes retroactively. This has resulted in architects and general contractors who are not familiar with how to make a home “solar friendly” and solar contractors who want to treat house plans as set in stone and design around suboptimal circumstances. This article will outline the key steps you need to take when integrating solar panels into your new home project.

Make sure your architect is aware that you plan to install solar panels before you finalize the placement and orientation of your home.

Home before solar

In order to truly optimize a house for solar, the architect needs to know at the onset of the project that solar is going to be an integral part of the home. This is because two of the key factors which make a house great for solar are the orientation and placement of the building. Ideally, any roof faces containing solar panels would  face south so the panels can take full advantage of the sun in our part of the world. In the northern hemisphere the sun’s path is an arch across the sky each day, starting in the east and ending in the west. When the panels are oriented to the south and there are no obstructions like trees or other buildings, the sun shines on them from morning to nightfall with the strongest, most direct exposure in the middle of the day. There are a few reasons it is preferable for the back of the house to face south:  1) people tend to prefer the panels to not be visible from the street, which could potentially have a negative impact on their curb appeal;  2) it is common for homes in our region to have architectural features, such as dormers, on the front of their homes which dictate the layout of the panels and usually do not complement each other aesthetically; 3) the other initial design aspect to take into consideration is the placement of the building on the property. People tend to place a house on a property to allow a large open yard in the front and trees close to the back of the house. This often leads to shading on the panels from the trees behind the home. Moving a home 100+  feet from a tree line to the South can drastically improve the production of a solar array. Depending on the property, there is not always a choice of orientation and placement, but if possible, it is best to follow the guidelines presented here.

Consider the placement of solar panels when designing roof details.

Solar panels on roofIt is also essential to consider the roof design and obstructions on the south-facing roof plane where the panels will be located. Roof designs with multiple hips, valleys, pop-outs, dormers, etc. force solar installers to design a system with panels spread out, disconnected, varying between landscape and portrait orientation, and which are generally not symmetrical. This not only affects the aesthetic, but it also frequently impacts solar panel productivity through shading by other parts of the roof and increases the labor required for the installation. Ideally those architectural features would be prioritized for the front of the roof. Rooftop obstructions such as vent pipes, skylights, satellite dishes and even chimneys also create challenges for solar designers. While some of these items like vents and exhaust pipes are integral to the function of a home, they can be located in a solar-friendly way. It is ideal to group these items in one part of the roof, either as high up along the ridge as possible, or as far out toward the edges of the roof.  This allows designers to shift the whole array rather than omit select panels, leaving gaps in the middle.

Ask your architect to include dimensions on the roof plans.

Solar plans

Another area where architects need to adapt to working with the solar trade is in drawing their roofing plan pages. Traditionally, architects do not include dimensions on roof plans because they are not necessary for the builders. Solar designers rely on satellite images to create their initial panel layout drawings. When a home is being built there are not satellite images available, so solar designers must rely on the house plans. Adding dimensions to the roof drawings is a small chore for architects, but it is a huge help for solar designers and estimators.

Use a home energy calculator to determine your projected energy usage.

Possibly the greatest challenge for solar companies bidding a new house project is determining the amount of electricity a new home will consume. When determining the number of panels required to generate 100% of the electricity a home will use, a solar estimator’s best friend is the customer’s past utility bills. They show exactly how many kilowatt hours of electricity that have been historically required to power a home. Obviously, this data is not available for a new house. This requires a solar estimator to collaborate with the architect or homeowner to project the energy consumption by evaluating each appliance, the quality of the insulating materials, the overall square footage, the number of windows and doors, etc. in order to calculate an estimated usage figure. Fortunately, there are resources available like home energy calculators which help break down the process into relatively simple questions. Using a home energy calculator to estimate the usage of a new home is the best alternative for estimating a home’s usage when past utility bills are not available.

Conduit Mount for Solar

Plan electrical infrastructure to conceal ugly conduits on your roof

Another challenge with integrating solar into a new home is also a wonderful opportunity. You have the opportunity to conceal the conduit which is normally exposed when retrofitting a home with solar.  With a new home, the builder can integrate the solar electrical infrastructure by asking the electrician install an empty run of 1 ¼” or larger conduit going from the attic into the main service panel. Solar panels can then easily be installed later when it fits into the construction sequence. Solar can be installed any time after the main service panel and final roof covering have been installed. As far as the roof covering, any flat roof substrate is okay. For slopped roofs corrugated metal, standing seam, and asphalt shingles are good, but tile and slate are not.

Integrating solar into new homes with these simple steps can be a relatively painless undertaking and achieve a better outcome than retrofitted solar. It is worth noting that with new home solar, as with retrofitted solar, even when it is not possible to optimize every aspect of a solar system to create a “perfect” array, (i.e. the orientation isn’t perfect, there is some shading, etc.), the savings from solar is so great that it still makes sense to invest regardless. So, don’t fret if you and your architect are not able to design your home without making a few compromises to your perfect solar system. Additionally, since you can integrate the cost for solar into your mortgage you are in a position to get the best value through financing at a lower rate.

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