With skyrocketing utility rates and climate change, the benefits of going solar are becoming increasingly difficult to ignore. From the moment your photovoltaic (PV) panels go up your electricity bills go down, often to $0 a month. Some customers even receive negative utility bills (you read that correctly). Your carbon footprint also shrinks and Planet Earth stays a little greener for a little longer. These benefits are immediate. And more important, they’re long-lasting. Most solar panels carry warranties of 25 years, but many PV systems last 40 years or longer. The question isn’t whether or not to go solar—it’s how best to do it. You have two main options:
Rooftop solar PV installations – These are probably what you’re most familiar with. The panels are built into new rooftops or retrofitted to existing ones.
Ground-mounted solar PV installations – With this approach, the panels are attached to the ground and slightly elevated—usually in your property’s backyard.
But what factors go into the decision-making process? Why would you ever choose one installation type over another?
The biggest difference between ground-mounted and rooftop solar installations is appearance. With many properties, rooftop solar panels are easily visible from the street, whereas ground-mounted systems are typically out of sight in backyards.
In the past, this was a very important distinction.
Some customers felt that solar panels were unsightly and preferred to hide their PV installations, making ground-mounted systems an obvious choice. In fact, many homeowners associations tried to make it impossible for neighbors to install solar panels on their rooftops.
But this has changed dramatically in the past several years, thanks to:
Shifting perspectives – What was once an eyesore has now become a badge of honor for an increasing number of homeowners and businesses throughout the country. There’s a certain satisfaction from signaling to neighbors that you’re a responsible, financially savvy citizen who cares about the environment.
Technological innovations – There now exists a range of solar panel designs for every type of roof. From crystalline blue to sleek black; traditional panels to thin-film panels. Even the most discerning solar customers can find panels that mesh seamlessly with their pre-existing rooftops.
You may or may not think solar is beautiful. But there’s nothing more attractive than having a healthy bank account. And who can argue with having a cleaner and more sustainable community?
This is precisely why many states have introduced solar bills of rights. Maryland, for example, makes it illegal for homeowners associations to prevent you from generating your own clean, free electricity with a rooftop solar installation.
Space and Exposure
Another important consideration is space. Many roofs are too small or have too many obstructions (chimneys, vents, skylights, etc.) to make rooftop solar viable. Depending on your property, a ground-mounted installation may be the only option.
The same is true of exposure. In the northern hemisphere, south-facing roofs receive the most direct and continuous sunlight throughout the day. If your rooftop is facing the wrong direction, a ground-mounted installation is probably better.
Other important considerations include:
Tilt – Depending on the slope of your roof, a ground-mounted system may be able to deliver higher electricity bill savings than a rooftop installation can.
Shading – With some homes and businesses, the roof is the only part of the property that receives direct sunlight, making ground-mounted systems a bad choice. With other properties, the roof is too shaded by surrounding trees, making ground-mounted installations a better option.
Assuming that you have plenty of yard space and the right type of roof, you may be better off with a rooftop solar installation, which would allow you to make optimal use of your backyard (barbecues, swimming pools and so on).
Ground-mounted systems usually cost more because they require extra materials (e.g. foundation cement, additional wiring). But when dealing with older roofs that require renovations and/or structural reinforcements, rooftop installations are sometimes more expensive.
However, cost is not nearly as important as payback period—that is, the length of time required for your monthly utility bill savings to exceed the price of your installation. In Maryland, for example, the average payback period is seven years, with many solar customers recouping expenses much sooner than that.
And remember that the payback period of your installation is calculated at today’s utility rates. As electricity prices continue to rise, your monthly savings actually increase; thus, you reach the break-even point that much sooner. So rather than focus on differences in cost, it’s better to concentrate on whichever installation type offers the shortest possible payback period.
To receive optimal power generation from your solar panels you used to have to clean them regularly. Debris and dust can have an adverse effect on PV panel performance. Because ground-mounted panels are easier to access, they’re also easier to clean and maintain. But with many of today’s solar panel technologies, regular maintenance is largely unnecessary. In a landmark study from UC San Diego, researchers discovered that the increased power output achieved through cleaning doesn’t usually justify the added cost and effort.
However, there’s one scenario in which access is important. Some solar PV systems are adjustable, allowing the panels to follow the sun’s trajectory (throughout the day or throughout the year). For most standard residential installations, this extra sunlight won’t have a major impact. But for larger PV installations, the long-term financial benefits of solar tracking can be significant. And the easy access to ground-mounted installations often makes it easier to capture those extra savings.
Some parents have safety concerns about ground-mounted solar installations—they don’t want their children exposed to high voltage electrical equipment. But, in fact, solar is one of the safest and most reliable energy generation technologies ever created.
With no moving parts, breakages and malfunctions are exceedingly rare. During Hurricane Sandy, New Jersey was one of the hardest-hit regions in the country, with millions of homes and businesses losing power. Yet in the aftermath of this freak superstorm, there wasn’t a single report of any major solar malfunctions throughout the entire state. In other words, solar is an extremely safe technology, whether you install it on your rooftop or in your yard.
So, which solar installation type is right for you?
Now that you understand the main differences between rooftop solar installations and ground-mounted systems, which type is best for you? The answer really depends, since every property is so different. Even within the same neighborhood, no two homes or businesses are identical.
The only way to be 100 percent sure is to have a licensed solar contractor inspect your property and review your long-term financial and environmental goals. If the numbers do work out, you could be looking at decades of higher savings and a much smaller carbon footprint.[box]Ryan McNeill is the president of Renewable Energy Corporation, one of the Mid-Atlantic’s largest residential solar energy companies—committed to installing quality, American-made solar panels and energy products for homeowners.[/box]