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Starting from scratch: Builder-oriented approach to installing solar panels
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Starting from scratch: Builder-oriented approach to installing solar panels

20 mins 20 Sep 2021
Builder or a prospective home buyer – knowing what goes into building a truly solar-friendly house can help you increase profits or cut costs. Below you will find a comprehensive guide that covers a range of topics pertaining to PV systems from a builder’s perspective, beginning from positioning and shading and ending with how to install solar panels.

Solar-friendly buildings are trending

A recent study has found that US citizens have been looking for houses with installed PV systems more than ever before. Their prices are only about 4.1% higher than those of similar properties, which makes such a purchase even more attractive. In some states, installing solar panels has become a matter of course: California building code requires all new homes to have a PV system.

Even if the clients you are building for are not going to set up a solar panel system, you’d better adjust your project to future solar energy improvements. It is highly likely they will thank you for that once they change their mind.

Solar-ready home vs. complete installation

If you tailor a house project for your clients, you can offer two options:
1.Solar-ready home. You make the home ready for solar panels, and then they are the prospective owners who will choose and install a PV system.
2.Complete installation. It requires more upfront investment since all the solar equipment needs to be purchased by the builder. At the same time, it offers opportunities for cutting costs, especially for medium and large scale projects: labor optimization and bulk purchases will have more of an impact. 

One more important thing before we dive into details. Your construction crew should not perform any part of the work without proper certification or training. What is more, the laws differ from state to state, and an experienced professional with numerous certifications can encounter problems outside his home state. Check if you meet all state requirements, and let the construction begin!

Constructing a solar-ready home

There are three main things to consider: positioning, roof design and wiring.

Expose solar panels to the most sunlight

Expose solar panels to the most sunlight

The position and orientation of the house should be considered before laying the foundation. The principle is simple: as much sun as possible should hit the roof of the building. To achieve it, the roof should face south – it is an ideal option in the northern hemisphere. If this is for some reason impossible, southwest or southeast direction might work just as well. A flat roof will be a universal option, allowing installers to pick any type of solar panel positioning.

When choosing the house location, avoid tall structures and trees – even a minimal amount of shade can significantly affect the functionality of the future setup. The same rule applies to the objects positioned on the roof itself, such as chimneys, antennas, vents, etc.

Design the roof to avoid shading

Design the roof to avoid shading

The National Association of Home Builders suggests the following rule of thumb: the slope of the roof should be equal to the latitude of the building site or up to 10 degrees less. For instance, NYC has a latitude of approximately 41 degrees. According to the rule, the ideal roof pitch is between 31 and 41 degrees.

To maximize the system’s efficiency, the NAHB recommends concentrating roof equipment on the north-facing side, as the panels themselves will be on the southern half. It’s best to tackle this during the planning stage, so that you will not need to relocate vent pipes, dormers or roof windows in the future. The key to a simpler installation that leads to an aesthetically pleasing result is a roof with fewer hips and valleys, as it allows for a more usable rectangular area.

The roofing materials should also be taken into consideration. Going for higher quality is more important than ever: the warranty for most solar panels is 25 years, but they tend to last considerably longer. The expected lifespan of materials must be targeted accordingly, because the presence of solar panels makes any repairs a difficult and expensive process.

Think where to hide wiring in advance

Think where to hide wiring in advance

Solar cables are constantly live while the sun is in the sky. They can run at up to 600 V, requiring special solar conduits. Furthermore, there are strict regulations that contain information on how and where these cables must be placed. It’s best to plan for this task in advance, not during the finishing stages. This will allow the bulky wiring to be easily hidden from view.

If possible, leave some space near the electric panel for inverters, meters and batteries. Some states specify the minimum and maximum allowed space between the electric panel and the solar equipment, and between the latter and the floor. It won’t hurt to account for this space in construction plans.

Installing solar panels. Detailed checklist for builders 

Now you're just one step from completing the installation – just choose the right equipment and mount it on the roof. Beware of legal issues though.

Permits and paperwork are rewarding, but take time

Permits and paperwork are rewarding, but take time

Getting solar permits is the most time consuming part of the building process. Any mistakes in the application can delay your project for weeks, so it’s worth checking twice. You can file for a permit with an Authority Having Jurisdiction (AHJ) in your area. Usually, but not always, it is your city’s planning office. The application form can be found on the organization’s website, but you can also contact them by phone for instructions.

Consult with local authorities before placing solar panels on the roof. There might be requirements for fire setbacks to allow firefighters to freely access and walk on the roof. These are usually located near ridgelines, valleys and other obstacles. Some states may also require 3 feet of distance around the modules.

Paperwork has its benefits though. Builders are eligible for up to $2,000 tax credits for all new energy-efficient homes. Various state incentives are also available. They can be found in the Database of State Incentives for Renewables & Efficiency by entering your zip code.

Laws and incentives differ from state to state and are subject to change. It makes incorporating research in the planning stage of your project a good idea. You can also learn about available state and federal incentives to be more knowledgeable when speaking to clients.

Solar equipment depends on your project needs

Solar equipment depends on your project needs

After completing the paperwork you can start choosing solar equipment and making orders. You will need to assess the size of your future system and determine its type. Once the needs of your project are clear, you can pick PV modules, inverters, charge controllers, batteries and other components.

The list of the necessary equipment may change depending on the project and needs of clients. There are three main types of PV systems: grid-tie, off-grid and hybrid. The usual choice for most residential buildings is a grid-tie system. It allows maximizing the consumption of harvested energy and selling the rest to the grid instead of storing it with batteries. You may opt for other system types if the project requires autonomy or grid interconnection is impossible.

Make sure you are certified for solar installation

Make sure you are certified for solar installation

If you want your own construction crew to complete the installation, make sure they have proper training and certification. It will dramatically lower the risk of delays and additional costs. Don’t forget that some incentives and rebates are only available for the PV systems that have been mounted by certified professionals.

One of the most cost-effective and simple ways to attach solar panels to the roof is racking. Depending on the type of roof material, this process can be more or less difficult. For example, metal roofs with standing seams appear as one of the most convenient options – PV modules are attached with U-clamps without any prior preparation. Meanwhile, the Spanish roof is one of the worst possibilities, since it’s hard to secure racking without breaking any tiles. For more information, check out How to install solar panels on a roof.

Final approval

Final approval

Finally, the system can start generating solar power. However, it needs an interconnection agreement to begin exporting energy to the grid. The contents of such an agreement depend on local regulations and the utility company you are dealing with. Normally you would have to submit the specs of your system along with other relevant information, but you can also expect a visit from the utility and local authorities.

Generally, it takes from a few days to a few weeks, so reaching out and asking about all the requirements in advance is the best strategy. After the final approval is granted, the PV system of your project becomes fully functional. If mistakes are avoided, it can be expected to work faithfully for many years to come.
Illustrations – Marina Fionova