1. The Roof (Azimuth)
A west-facing roof isn’t a dealbreaker anymore
Let’s start with the roof. An ideal roof has a large, uninterrupted surface facing south, southeast, or southwest. However, given advances in solar module technology and efficiencies that make them more affordable, a purely due-south roof is no longer a prerequisite. A well-producing solar home should have an orientation or “azimuth” within 90 degrees of true south. The closer the solar azimuth is to 180 degrees true south the better the system will produce. Roof angles are also something to consider. A roof pitch between 5 and 12 is ideal. The lower the slope, the less production you will see in the winter.
A good roof for solar is an empty roof; uninterrupted. That means keep your chimneys, vent pipes, dormers, and skylights away from that nice big southern expanse! We can work around these things if we have to, but if you want to maximize production, have wide-open spaces.
Shade on panels means less production
When you’re deciding where you want to put your home on your land it is best to avoid any trees on the solar side. Planting a gorgeous maple in front of your array will mean shadowed solar panels in a few years. Go ahead and tuck the northern side of your home into the trees, but any tree that casts a shadow on your solar roof for any significant portion of the day is no good for your system’s production.
3. Roof Material
Anything but cedar and slate
Roof composition really matters when building a house with solar. Asphalt shingles or metal roofs are great, slate and cedar shingles are a no go.
With asphalt roofs, it is important to choose a shingle that will last as long as your solar system. A 30-year rated shingle would be best. A minimum 3/8” sheathing on the roof is recommended. Standing seam metal roofs are ideal because the roof material will last as long as your solar system. Corrugated metal roofs are also an option. Our solar attachments are happiest if your corrugated is installed directly on top of plywood decking.
4. House Electrical
A benefit of incorporating solar into your new construction is that we will often be able to integrate the wire or pipe run into your building. We will work with you or your contractor on the specifics to make sure that you get a high-producing and aesthetically-pleasing solar system.
Our licensed electricians can run conduit and wire while your walls are open. Then, as soon as you have a roof, we’ll be happy to come out, install your solar system and celebrate with you as your meter runs backwards.
5. PV Systems Add Weight
A standard PV system adds less than 3lbs per square foot on the roof. Making sure your roof can support this weight across the house is important and your contractor should be able to factor this added weight into the design.
6. What We Need From You
In order to facilitate a Design and a cost estimate for your PV system, we will need some information about your project. Some of the things we will need are:
- Contractor Phone Numbers (if any)
- Design/ Architectural Drawings
- Structural Information
- Electrical Information
- Building Timeline
To summarize, when building a house with solar, you want a roof that is unshaded and free of obstructions such as dormers, chimneys, or skylights; made of solar-friendly materials such as metal or asphalt shingle; and structurally supported by accounting for the weight of the panels and leaving room for the necessary electrical work to connect the panels to your circuitry.
We hope this information will be useful while you work on your home. Remember these are strictly recommendations and you should build your home to how you prefer it. If you (or your contractor) have any questions about how to better integrate your new home project into the solar system, our engineering team will be happy to assist you!
Have any specific questions, we’re happy to answer them here or via email.