April 17, 2018 Solar Energy Written by Greentumble
solar panel mounting
While even ambient sunlight hitting solar panels can

generate power, the highest collection period is during peak sunlight hours when sunlight hits the panels at a direct angle. Accordingly, it is the goal of the solar panel installer to place panels at a trajectory that optimizes collection from a direct angle.

In the northern hemisphere, the sun hits most directly from an angle at true south. The angle of tilt to align with true south is close to the latitude from the equator in mid-afternoon [1].


Installing solar panels on the roof

Considering rooftop installation, that may not have been an objective when your house was built and the usable space for panels may be limited. Too, you may have architectural obstructions like dormers, skylights, a chimney, roof vents or a satellite dish that further limit possibilities.

It may be that taller buildings or large trees on neighboring property block a significant portion of the sunlight hitting your roof.

Solar panel systems have developed to the point where many of these considerations can be addressed. For example, the panels do not have to lie flat against the roof, but can be tilted toward the sun’s trajectory. Shading one portion of the panels does not necessarily affect the performance of the balance of the system. 

Rooftop solar tracking system

It is even possible to install a tracker system where rooftop panels can move to follow the sun’s trajectory, thereby collecting more of the most powerful sunlight. However, rooftop tracking systems, while available are not widely used on residential rooftops in the United States as the sun’s movement may not impact the panel production enough to offset the cost.

The system and installation are both more complex, more invasive to roof integrity due to moving parts, more likely to require repairs for the same reason and too, it consumes energy to power the movement of the panels [2].

Assessing the condition of your roof

If you have both the roof space and the ground space and are weighing where to mount solar panels, another consideration is the type and anticipated lifespan of your roof. The solar panel system you are considering may warrant a lifespan of 25 years, while your present roof may only have 10 more years before it needs to be replaced.

Yes, solar panels can be removed and reassembled, a roof replaced and the system re-installed. The initial installation likely required lag bolts drilled into the roof to hold the mounting rack, and was likely designed with a roof replacement so that the solar panels can be removed and replaced without the necessity of removing the mounting structure.

The necessity may be contingent upon the choice of new roofing materials, but a skilled roofer should be able to work around an existing mount.

Do remember that there is the added expense of removing and reinstalling a roof solar panel system, presently estimated between $500 and $1500 [3].


What about roof leaks with solar panel construction?

The belief that solar panel installations frequently result in roof leaks has been discredited. Still, any homeowner is rightfully cautious of unnecessary roof repairs that can further compromise the integrity of the roof.

Technologies are rapidly advancing and new options are now available like tile roofs capable of collecting solar energy, but what if you are not in the market for a new roof and you would like to take advantage of the federal tax credit of 30 percent this year?

If you do not have the space on your roof to generate the power you would like, a ground mount array may be a better option for you. You may even have the space to get off the grid entirely.

When are ground-mounted solar panels better option?

Ground mount systems, if you have the space, can offer more flexible options to capture direct sunlight, especially if there are no obstructions to the sunlight. You may have more space for a greater number of panels than your rooftop can fit. You can adjust the orientation exactly where you’d like and the movable parts of a tracker will not impact the integrity of your roof.

Maintenance is simpler and safer as you can simply walk around the panels to access the panels and wiring rather than having to climb the roof. It can be easy to keep panels clean, remove snow and make any necessary repairs.

A ground mount system will likely require a building permit and have to comply with local regulations governing wind resistance, but they do have a huge advantage of allowing the free flow of air under the panels and not within inches of a hot rooftop. Panels perform less efficiently if hotter than 77 degrees Fahrenheit or 25 degrees Celsius, the most efficient temperature for collection [4].

Installation expenses will vary, depending if excavation is needed for the ground mount system or nearby obstacles need removing and there is the expense of digging a trench for wiring, but in many situations it is well worth getting a quote for what may be involved.

In the article on the positive effects of solar farms on biodiversity, we probe the challenge of the skepticism to change where beauty is an issue, especially where home values or tourism coffers are at stake. We have all read about, or possibly been involved in the furious controversy surrounding proposed windmills on ridgetops.

The naysayers decry destruction of pristine views, while proponents see the windmills as beautiful as a tree line, emblematic of a world advanced enough to embrace clean, renewable energy and the windmills conjuring dreams of Don Quixote’s quest for justice.

While the question of aesthetics is certainly subjective as illustrated above, it can become a tangible concern when homeowner associations or zoning concerns, like historic district regulations ostensibly govern a proposed installation [5].

You may have a situation where rooftop panels will not be approved by your homeowner association for not blending into the style or color scheme of the neighborhood, yet a ground mount system out of view will be approved. States are now passing legislation promoting solar access rights which can limit local private restrictions [6].



[1] http://www.solarpaneltilt.com
[2] https://news.energysage.com/solar-trackers-everything-need-know
[3] https://news.energysage.com/solar-panel-roof-replacement/
[4] https://www.civicsolar.com/support/installer/articles/how-does-heat-affect-solar-panel-efficiencies
[5] https://www.nachi.org/hoa-solar.htm
[6] https://www.seia.org/initiatives/solar-access-rights