New Solar Shingles Get Rid of the Ugly, Complex Hassle That Can Be Part of Rooftop Solar

We visited the factory where GAF Energy's Timberline Solar is made, and got to see one of its first installations.

A new kind of roof shingle called Timberline Solar blurs the lines between roofing and solar. Its form, appearance and installation are barely distinguishable from asphalt composition shingles, yet each one is a solar panel. If it can capture the public's imagination as elegantly as it captures the sun's energy, it could seriously increase the 10% rate of US homes that get solar when a new roof goes on.

Timberline Solar shingle being shown to CNET's Brian Cooley

GAF Energy's Rey Holmes demonstrates the lightness and thinness of his company's solar shingle.


As important as its physical form, Timberline Solar is sold and installed by existing roofing companies -- as opposed to solar companies frequently known for bombastic radio commercials and "free" or "act now" offers. Attracting homeowners solely via the roofing industry is possible because GAF Energy has designed Timberline Solar to be installed like a common asphalt composition roof shingle, that is, with nail guns and string lines (lag bolts and metal racks are nowhere to be seen). "This is meant to be a roofing shingle that happens to produce electricity," says Rey Holmes, vice president of services and product at GAF Energy.

Roofers install Timberline Solar

A roofing crew installs Timberline Solar using a conventional nail gun and snap line. Electrical connections along one edge just snap together.


Prior to installation, Timberline Solar doesn't look quite like a roof shingle nor a solar panel: It's a long, narrow piece of thermoplastic about a quarter inch thick, bonded to an integrated solar panel on top. The whole thing is a single, waterproof unit that you can walk on. Electrical wiring connecting each shingle is hidden under a low-profile plastic channel along the edge of a set of shingles. That wiring feeds a single inverter on the side of the house that converts the panels' direct current output to alternating current used in the home. 

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All types of solar panels must go through this conversion process -- solar installations are eventually an electrical job. The other method is to have a small "micro inverter" mounted at each solar panel, which has some benefits over single inverter arrangements. The roofers I spoke to subcontract that job to a local electrician rather than performing it in-house. 

Walking on Timberline Solar panels

Timberline Solar shingles lay as flat as conventional roof shingles, though they have a more horizontal look that lacks the tabbing of the shingles around them. Still, the effect is less jarring than rack-mount solar.

GAF Energy

When solar is part of the normal roofing technique, it eliminates one of the most unnerving elements of a solar install: lag bolts, which are typically 3 and 1/2 inches long, drilled and screwed through the roof into the underlying framing. Solar installers will say they've done this process for years with very few leaks, but I imagine someday we'll look back and wonder why millions of homeowners consented to it. My own installer uttered the dreaded "oops" as they missed the center of a four-inch wide roof joist and split it quite visibly in my living-room cathedral ceiling. Perhaps the worst part is that I wasn't really surprised when it happened.

Solar panel lag bolt appearing as long as a Roku remote

"Oops" is something you never want to hear when a conventional solar crew is putting these lag bolts into your roof. But it happens.

CNET/Brian Cooley

For now, GAF Energy manufactures Timberline Solar in the US, helping ease residential solar's dirty little secret: Typical Chinese-made solar panels burden the environment with a large amount of up-front pollution due to their coal-fired electricity plants. GAF Energy's plant in Silicon Valley is powered by one of the cleaner electric grids in the country.

Unlike the splashy but troubled solar roof technology from Tesla, Timberline Solar emanates from a sister firm of GAF Roofing, the largest maker of roof shingles in the world. GAF Energy executives take great pains to point out that it's a separate company. But the shared first three letters of its name together with its 50-year roofing warranty will carry a lot of weight with homeowners, who are probably more accustomed to gambling with new tech on their wrists rather than on their roof.

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With so much variation of conventional solar panels on the market, it's hard to pinpoint just one for electrical comparison. But when I compared Timberline Solar to the panels I recently put on my California home, I came away wishing I'd waited for this new product. Though some of its raw specs fall short of the high-performance Panasonic EVPV370 panels I'd installed, Timberline Solar would have been a generally more satisfying way to energize my roof. While GAF Energy insists that a comparison to Panasonic EVPV370 panels is unfair because they're more advanced than average, Timberline Solar will need to succeed in a variety of ways, not just because they look good and install easily.

GAF Energy
Timberline Solar

Cooley's Panasonic EVPV370 panels

System size
(to generate 8.8 kW)

607 square feet

451 square feet

Wattage output
(per square foot)

14.5 watts

19.5 watts

Temp coefficient (PMax)
(power loss per degree above 77 F)



Output decline in year 1



Output decline in 2 to 25 years



Guaranteed output
(at end of 25-year warranty)



An interesting aspect of a Timberline Solar's power output is that its shingles can be installed on parts of a roof that might otherwise be nonwalkable dead zones with a conventional system. Since conventional panels can't be walked on, building codes require access paths to be left open around them. Timberline Solar's walkable surface should obviate that waste, potentially thus achieving more system power even if it might generate less power per square foot. At least one Northern California roofing contractor told me that building inspectors are still warming up to the idea that Timberline Solar doesn't need a roof path open around it.

Walkable space around solar panels

Conventional rack-mount solar panels can't be walked on, so building codes require dead space around them for roof access, potentially reducing their total system output.

CNET/Brian Cooley

This isn't GAF Energy's first attempt at reinventing rooftop solar, though its previous DecoTech technology was less distinct from conventional solar panels. Plus, it came at a price premium that I didn't find justifiable for its moderate aesthetic benefits and due to its risk of becoming an orphan technology.

Pricing solar roof technology isn't like pricing a TV or laptop. It's all bound up in a larger bid for the entire roof, and no two roofs are the same. GAF Energy says Timberline Solar currently costs the same as a new roof with a separate rack-mount solar system, but knows that undercutting the conventional combo is key. As is the case with electric cars, extensive adoption relies on the product becoming cheaper and better than anything else, not just more technically elegant at the same price. 

"Our mission is energy from every roof," says GAF Energy's Rey Holmes, "not just energy from every roof where there's a homeowner who can afford it." Regardless of price parity, this new solar tech deserves a hard look from homeowners interested in solar, as well as from those who decided they weren't.

Article updated on April 15, 2022 at 5:50 AM PDT

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Brian Cooley
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Brian Cooley Editor at Large
Brian Cooley is CNET's Editor at large and has been with the brand since 1995. He currently focuses on electrification of vehicles but also follows the big trends in smart home, digital healthcare, 5G, the future of food, and augmented & virtual realities. Cooley is a sought after presenter by brands and their agencies when they want to understand how consumers react to new technologies. He has been a regular featured speaker at CES, Cannes Lions, Advertising Week and The PHM HealthFront™. He was born and raised in Silicon Valley when Apple's campus was mostly apricots.
Expertise Automotive technology, smart home, digital health. Credentials
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