Making a home Solar Ready means providing the plumbing, wiring, and structural changes needed to support solar thermal collectors and PV modules.
These modest upgrades make future installations much easier, less costly, and more durable.
Building America experience and market research suggests that when it comes to ZEH, communi-ties that make the technology part of the house package, rather than an option, do the best job of marketing solar. However, solar ready is a small step for builders who want to get started, but are not ready to commit to full installations.
Making a home solar ready helps to retain the advantages of new construction, such as avoiding after-market roof penetrations, and will help build-ers comply with programs that require offering solar features to consumers.
Perhaps the most important step in using solar energy is the site evaluation and design.
Site planning that exploits and protects solar exposure is critical to making a home and community solar ready for both PV and solar thermal technologies.
Clearly label all end points for wires or pipes so subcontractors, homeowners, maintenance workers, and solar installers know their purpose and where the materials are located. Similar information will be needed for the location of structural rein-forcements. This information should also include
the intended placement for potential equipment, such as arrays, collectors, tanks, inverters, and switches. Diagrams and notes should be included in the homeowner’s manual. In addition, a copy of the wiring notes and diagrams should be left in the electrical panel. Post a sign or label on the electrical panel door indicating that the home is SOLAR READY.
See the respective chapters on PV and solar thermal installations and site planning and orientation for more details.
Design the home as if PV were going to be installed. Here are some elements to include:
• Design the orientation and pitch of the south-ernmost facing roof to maximize solar gain, although there is a great deal of flexibility in both the direction and angle.
• Design the roof vents, chimneys, gables or other obstructions to sit to the north side of the planned array. Do not shade the part of the roof where a potential PV array or solar thermal collector could be installed.
• Ensure that the roof structure is strong enough.
Design structural support into the roof to handle the weight of a rack-mounted system.
• Design space for inverters and disconnects near the main service panel.
Builders’ & Installers’ Brief
• Use the techniques found throughout this document to make homes solar ready.
• Making provisions for solar installation up front will make future installations easier, less costly, and more durable.
Plan for solar at the earliest stages of site design and construction.
• Make sure the main service panel has space to handle a power input breaker.
• Pre-wire or install empty metal conduit from the roof to near the main service panel to handle wires from the future array to the future inverter. 1”
conduit would support most residential systems.
A conduit will also be needed from the inverter location to the main service panel. If you are preparing a very large house you may need to run two or more conduits from the roof.
• Provide enough room in the breaker box for a double-pole 30 A breaker (solar electric feed).
• Provide a vertical wall area to mount an inverter in the mechanical area of the house.
• Minimize the distance (wire run) from the array to the inverter.
• Install an electric disconnect switch for a potential future solar electric system.
• If stand-off mounts or racks are needed, install them before the final roofing material is installed to ensure proper flashing.
Preparing for solar thermal:
• Design the orientation and pitch of the south-ernmost facing roof to maximize solar gain, although there is a great deal of flexibility in both direction and angle.
• Design the roof vents, chimneys, gables, or other obstructions to sit to the north side of the planned array. Do not shade the part of the roof where a potential PV array or solar thermal collector could be installed.
• Ensure that the roof structure is strong enough.
Work with your designer or structural engineer to ensure adequate structural support. Note that in some designs structural lumber is added as a convenience for easy installation rather that to actually support additional load.
• Install 3/4” copper pipe for both cold and heated water from the roof to the space where hot water storage tanks would be located. The pipe will need to be capped and accessible on the top. The bottom should dead end until the solar system is installed. Insulate the pipe as described in Chapter 3: Solar-Thermal Water Heating.
• Run sensor wires parallel with copper pipe.
Electric cable may be needed for a potential pump.
• Allow space near the water heater for necessary equipment including hot water tanks, valves, pumps, heat exchangers, expansion tanks and other needed equipment.
• If stand-off mounts or racks are needed, install them before the final roofing material is installed to ensure proper flashing.
(left) Structural changes may be added to ensure adequate support or just to make installation easier.
(right) Set off mounts installed before roofing to allow for proper flashing. Photo courtesy of Namaste.
Resources and References
Lubeliner, Michael, Andrew Gordon, Adam Hadley, and Michael Nelson. 2004.
“Introducing ‘Solar Ready’ Manufactured Housing.” Proceedings of the 1994 ACEEE Summer Study on Energy Efficiency in Buildings, American Council for an Energy-Efficient Economy, Washington, D.C.
Seiter, Doug. 2006. “Are You Solar Ready.” Home Builder, July 2006.
(left) Pre-plumbing for solar thermal collectors is especially important in inaccessible areas.
(right) Pre-wiring or installing empty conduit allows for the easy installation of PV systems. A junction box with some flexibility can be moved to the appropriate location to match a future PV array.