What actually happens during a residential solar installation

October 14, 2014

Step-by-step, here’s what to expect when you go solar:

You get a site assessment, in which a trained technical consultant meets with you to listen to what your goals are, and to gather information about your home’s solar potential. This sales consultant will spend some time up on your roof, using a tool like the Solmetric SunEye to measure the impact of shading from any nearby trees, roof vents, and so on. The SunEye factors in things like the orientation and pitch of your roof, geographical latitude, and time and calendar date variables to help the consultant locate the optimal positioning for the array of solar panels.

If you have any special roofing considerations, the solar installation company may subcontract that part of the job to a roofer. For example, my PVC membrane roof required special “boots” to be constructed to ensure that roof penetrations for the solar racking and mounting structure would be seamless.

Photo of roofer working

A roofer preps my PVC membrane roof. Surprisingly, this was actually the most time-consuming part of installing the array.

Next the racking and mounting system is installed. This includes clamps, mounts, and the long rails on which the solar panels are eventually attached. At this point you can really begin to visualize what the array will look like on the roof. The racking and mounting equipment for my array comes from a Washington state company called SunModo.

Solar panels produce DC power, which must be inverted to AC power in order to be usable in your home. This means that a key component of your array is an inverter. You can get a string inverter (or two), which is usually located in the garage, or you can now get microinverters that are much smaller in size and are located on the back of each solar panel. Microinverters are particularly desirable to mitigate the impact of shading, because they free individual panels from being dependent on power flowing from neighboring panels (as they would in traditional string arrays). In my case, because I do have a couple of trees in the backyard, I opted for microinverters from Enphase, the California company considered a leader in the field. The solar installers attached the microinverters to the racking rails, before installing the panels themselves.

Photo of microinverter

The Enphase M250 microinverter is optimized for higher-powered solar panels and carries a 25-year warranty.

Next the solar panels themselves are attached to the racking and mounting system. In theory, this is one of the simplest parts of the overall installation work. But I was glad that my installers really took their time to align the panels precisely along the rails, so the appearance of the array would be as clean and professional as possible.

When it comes to residential installations, the neighborhood “eye-test” is more important than you might think. You want your home’s solar array to be aesthetically pleasing, not an eye-sore.

And finally, all the electrical work of the array is prepared, including connecting the microinverters to the panels, and running wiring down from the array to a photovoltaic load center box, and from that box to the home’s power box as well as two utility meters.

Aside from the panels themselves, perhaps the big stars of any new solar array are these two meters: one a new “production” meter, which records the total power the solar panels are producing either for use in your home or back out to the grid; and the other is most likely your existing meter from the utility, only now transformed into a “net” meter, able to spin backwards if your solar panels are actually producing more power than you are using in your home at any given moment.

And there you have it! There really aren’t that many moving parts to this technology, so installations can be pretty quick and painless compared to other home improvements you might make.

Up next: Money, quality, aesthetics, and ROI. Some key decisions to make as a solar “consumer.”

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