Solar roof shingles, also known as photovoltaic (PV) shingles, are designed to integrate with and look more like standard roof shingles and tiles. For some, this is a more aesthetically pleasing alternative than traditional solar panels.
There are solar tiles by SRS Energy that are designed to blend in with clay tile roofs. Dow Chemical has produced a shingle that can be nailed to the roof just like an asphalt shingle, and there are a number of others that integrate with concrete tiles.
The end result is a roof with some dark blue or purple shingles or tiles that is pretty inconspicuous from the curb.
However, it’s not all about looks. Appearances aside, how do PV shingles compare with a more traditional solar panel?
I compared the installation logistics, efficiency and costs between shingles and panels and this is what I found.
Many of the logistics around PV shingles and roof-mounted solar panels are the same. They both produce DC current and therefore both require an inverter to convert this to the AC current used in homes. Both systems can be wired into the grid network so that excess energy is fed back into the grid, earning you a credit with the utility company. Essentially, everything about the system, except the format of the PV cells themselves is the same.
Where they differ, is obviously on the roof itself. The PV shingles or tiles are designed to literally be the roof, and so installation is with standard roofing components. PV panels on the other hand are designed to go over your roofing material and are much heavier due to their support structures. This means that an installer will need to calculate the load your roof can handle to ensure it can support the panel system.
Installation time is obviously very dependent on the size and nature of the project. However, a household PV shingle system is estimated to take 10 hours on average. Installation of solar panels can take 2-3 days and that doesn’t take into consideration any structural adjustments that need to be done to the roof to carry the increased load.
The roof space needed is essentially identical for both panels and shingles. A 2 KW system, which would supply about 35-50% of the average household’s energy demands, would require about 40 tiles and take up 172 square feet (16 square meters) of roof space. A 2 KW system in panels would require approximately twelve 185 watt solar panels in the same amount of space (approximately 172 sq ft (16 sq m)).
Another consideration is that PV shingles and tiles are still relatively new. My searches on various forums for electricians, and professional installers yielded more questions than answers about the technology, so it might be harder to find retailers as well as professionals with much experience using them.
Solar roof shingles are on average 10-20% less efficient than solar panels. The shingles are restricted to being at the angle of the roof and so not all roofs are ideal for this design.
Panels, however, can be mounted at a different angle to the roof line to maximize exposure to the sun.
Solar roof shingles are more expensive by far – often double the cost of panels. The average PV shingle installation will cost somewhere between $25,000 and $45,000. This is despite the fact that installation costs are cheaper than panels as they take less time to install. You also save on the cost of your regular roofing material as using PV shingles means you need less regular shingles.
Like solar panels, PV shingles are still eligible for rebates, and government incentive programs, so this does help reduce the cost.
In both cases, retrofits usually cost more. In terms of solar roof shingles, it’s easier to fit them when a new roof is being installed rather than removing a number of shingles/tiles to retrofit them. It’s also easier to incorporate solar panels into the design of a roof, eliminating the potential need to incorporate additional support to an existing roof so it can carry the extra weight load.
Both solar panels and solar roof shingles are designed to last between 20 and 30 years, which is essentially the same life expectancy as most roofs.
So, if it’s simply a matter of aesthetics that’s holding you back from installing solar power technology in your home, then it’s worth considering solar roof shingles. However, the much larger price tag and slight compromise in efficiency is probably enough for most homeowners to overlook the ‘look’ of solar panels. NBC 6 News Miami discusses solar tiles for roofs some more in the video below.