Solar Q&A

Solar Uncertainty

Q&A with Howie Michaelson, Catamount Solar

Howie Michaelson (who has lived in a solar, off-grid home for 15 years) answers solar-related questions in a simple, clear fashion. Submit your questions to G.E.T. or  howie@ctamountsolar.com  for inclusion in future editions!

Q: My partner wants to put our new solar panels on the barn roof because it is safer and better looking there. I have always heard that it is better to put it on a ground rack so we can clear snow and adjust the angle. Who is right?

A: There are plusses and minuses to roof and ground mounting options, so you could say you are both right, both wrong, or (being more political) somewhere in between. Here is a list of many of the issues you might face when making this decision.

• Roof-mounted systems are typically less expensive than ground-mounted systems, simply for the reason that with roof-mounted systems, the structure for holding the solar rack is already built — the roof itself. Ground-mounted racks need a substantial structure built to hold them in place. It is as important to hold the rack down -– think high winds blowing against that nice “solar sail” of ground-mounted panels.. (If you have any doubts or concerns about the loads that solar applications might add to a roof, or structure, consult a qualified engineer).
• Some folks enjoy the look of a solar array in their field where they can see it and appreciate it (and perhaps show it off), but many others would rather the array fit more unobtrusively into their landscape by “hiding” it on a south-facing roof.
• While roof systems are less expensive, and perhaps generally accepted as more aesthetically pleasing, many people do not have a largely unshaded, reasonably south-facing roof to donate to the project, leaving them with a more easily sited south-facing ground mounted array as the best option.
• Grid-tied, net metered solar systems produce the bulk of their electricity in the sunnier half of the year, so they are not overly sensitive to lost wintertime production due to snow covering the array. However, off-grid systems are trying to maximize wintertime production and therefore benefit from as little snow coverage as is feasible. Ground-mounted arrays (particularly top-of-pole-mounted rack systems) are seasonably adjustable to maximize production year round. They can allow for a steep wintertime tilt in order to minimize snow collection, and are more accessible for careful manual snow clearing when necessary. Roof-mounted systems are often harder to reach and at a pitch that doesn’t shed snow as quickly as might be desired in off-grid situations. Therefore, ground mounts are often the rack of choice for off-grid systems.

So as noted above, there is no a simple answer to the question of where to put a solar array. The answer, as is so often the case, is “It depends!” Your solar installer should be happy to go over the options available to you, discussing the advantages and disadvantages to each. In the end, of course, you can make the final decision, based on your own needs and aesthetic concerns. And it never hurts to get a second professional opinion when making such a significant financial investment.