Are Solar Shingles Better than Solar Panels on an ADU?

By Buz Artiano, BuildX | September 2026

Watch: How Solar Really Works for Builders, Homeowners, and ADUs | BuildX Podcast #35

You've seen the ads for a roof that makes its own power, but you figure it's either not real or it's way out of your price range. We understand why that's your first thought, but you don't want to carry doubt like that into an ADU project, because you are about to buy a roof either way. This is the window of time when comparing a solar roof with panels doesn't cost you anything. But every week you push the decision back it gets more and more expensive.

My name is Buz Artiano, founder of BuildX. We've built dozens of ADUs all over Massachusetts, but most of our projects have been on the South Shore and in Plymouth County. We do everything from design and permitting all the way up through construction and the final walkthrough. That means we are the ones there with you when a septic evaluation comes back short, when lot coverage tells you that you have to build a smaller ADU, and when the by-right permitting path turns out to have other local restrictions that you weren't aware of. Roof decisions are made right around that same time. They get made early, they get made once, and they are expensive to go back and change.

We talked to Chris Johnson about this on our podcast. He's the Director of Business Development at Isaacson Solar. Isaacson is a certified Tesla solar roof installer with systems running in this area right now. He didn't answer us with a sales pitch on solar, he said it was simply a trade, with numbers attached to both sides of it. What we've learned after building a lot of these ADUs is that the trade works differently on an ADU than it does on a 3,000-square-foot house, and you should understand that before you make a decision.

So Which One Should I Put on My ADU, Tiles or Panels?

Neither product wins every time. The choice comes down to how much roof you have, how much of that roof solar panels can legally take up, how much you care about the way the ADU looks from the street, and what the two systems cost when you compare them honestly.

Here is the trade as Chris Johnson described it from jobs his crews have installed. Solar roof tiles run about 15 percent less efficiently than traditional panels. You can also fit about 15 to 20 percent more of them on the same roof. So those two things basically cancel each other out, which is exactly why this is not an obvious decision. These are numbers from installed systems, not manufacturer specifications, so compare them knowing that.

What tips the decision one way or the other is everything else around it. Like the shape of your roof, the elevation people see from the street, and the price difference between the two quotes. Those three variables are where an ADU is different from a full-size house.

Solar Shingles Escape the Roof Clearance That Shrinks a Panel Array

A system of panels never gets the whole roof. They are rectangular and they mount on top of a finished roof, and fire code requires clear access pathways and room to walk around the outside edge and the ridge so firefighters can work on a burning building without stepping onto an energized solar panel. That space gets deducted off the top before a single panel is placed. The current state fire code is the Massachusetts Comprehensive Fire Safety Code, based on NFPA 1, 2021 edition with Massachusetts amendments, and the exact dimensions and how you can set up panels on your specific roof are set there and enforced by your local fire official. You can double check everything for your address at mass.gov.

Solar roof tiles are the roof. They are the surface, they don't sit on top of the roof, so they can use that space around the perimeter and pathways. That is the whole thing behind getting more coverage. When Chris put a number on it, the reason was obvious to anyone who has ever designed a panel setup. Panels have to stay back from the edges and tiles don't.

Here is where an ADU stops acting like a house. Perimeter shrinks differently than area. Cut a roof in half and you lose half the square footage while giving back nowhere near half the edge. That means the required clearances for firefighters takes a big chunk out of a small ADU roof, whereas the same amount of clearance takes out only a small chunk of full-size roof. So the extra coverage that tiles give you is worth more on a small building than the sales pitch might suggest. That's why we push people to make a decision on this during design. On a building this size, the difference between a roof that can give you the space for a productive solar panel setup and one that doesn't comes down to one early decision about how large and how simple the roof is, and that decision is free to decide on paper, but very expensive later.

What Are Active and Inactive Tiles, and Will I See the Difference?

A solar roof is not built entirely from power-producing tiles. Chris Johnson split them into two kinds. Active tiles sit in the open middle area of the roof away from the edges. They are full size and they generate power. Inactive tiles are the ones at the perimeter that have to be cut to meet the roof line, and cutting them means they can't produce electricity anymore. They just act like regular tiles at that point, just a weather surface and for appearance, but they're not part of the electrical system.

That matters for two reasons. The first is that a solar roof doesn't produce from every inch of the roof area. It produces only with the middle tiles that don't have to be cut, which makes the layout drawing especially important to pay attention to. The second reason is appearance, which is why most families ask about a solar roof to begin with. Chris's experience says that depending on how the sun hits the roof, you will not necessarily be able to tell the two apart from the ground.

Can I Put a Solar Roof on Only Part of My ADU?

Yes, and on an ADU this is what we would price out first. Tiles don't have to run across the entire roof. Chris Johnson's answer was that partial coverage depends on how simple the design is. To a builder that means a straightforward roof with few planes, few penetrations, and clean transitions give you more freedom to split it up.

Isaacson evaluated exactly that on a house in Truro. The homeowner put the Tesla solar roof on the south-facing roof and asphalt shingles on the back to keep costs down. That is Isaacson's project, BuildX did not build it, but it's a great example to use for this instance. Solar tile goes on the plane that faces the sun and the street. Conventional roofing goes where nobody sees.

For an ADU sitting in a backyard, there's logic here. The elevation your family and your neighbors look at every day is often just a single face of the roof. If a solar roof is on your list because of how the building will look, buying solar tiles for the visible face and doing the rest in regular shingles answers the appearance question without paying for it twice.

What Belongs in the Quote Comparison Before You Choose?

This is where the decision actually gets made. Chris Johnson gave us info about efficiency, coverage, tile behavior, and a real example of a roof job. He didn't give us a price at all and he didn't compare pricing of a panel array with a conventional roof. We don't want to guess at price, but what we can give you is the exact language that gets you both quotes on the same page.

Ask both bidders to price the same building against these five things:

• Total installed cost delivered as a complete, weathertight roof, so the tile quote is not competing against a panel quote that leaves out the roof underneath it. Otherwise you're not comparing apples to apples
• Estimated annual production in kilowatt-hours, which is the same unit your electric bill is measured in, you need to know more than just how many panels or tiles they will be installing
• The layout drawing showing which tiles arrive active and which ones will have to be cut, or how much of the roof solar panels can take up after fire department clearance is figured in
• The product warranty and the workmanship warranty. Make sure they give you these as two separate items on each product
• The service plan for year fifteen, including who removes and reinstalls the system when the roof needs to be worked on

The line item people forget is what's underneath. A solar panel array is quoted on top of a roof you are already paying for. A solar roof replaces that roof so you're only paying for one thing. If you compare a solar roof quote against a quote for just panels, then the tiles look a lot more expensive than they are. Compare it against a panel quote that includes the shingles and the tiles look cheaper. Make sure that the numbers you're comparing are both for a finished roof.

Situations Where a Panel Array Serves Your ADU Better

We design ADUs to accept solar, and the solar tiles make our buildings look better in photographs, but that doesn't mean we prefer them.

Panels are the better choice more often than not, and here is when that is clearest. If the ADU sits behind the main house where the roof is out of view, tiles just means you are paying for aesthetics that nobody is going to see. If the roof has multiple planes, dormers, or a run of penetrations, you end up with less production because of all the cut tiles and your advantage disappears. If the budget is tight enough that the roof decision is competing with the kitchen, panels give you the same electricity for less money and leave you room to add capacity later.

We want to be clear on one more thing. BuildX is not a solar contractor. We build the ADU, we frame and sheathe the roof to accept whichever system you choose, and we do things in a certain order so the solar crew isn't interfering with our work. The solar roof product has to use an installer who is certified for that specific product, and not every solar company has that. If a solar roof is what you want, confirm the certification before you sign anything.

Which Roof Is Right for the ADU You Are About to Build?

The trade between tile and panel is close enough that price decides it, and price is the one number this conversation could not hand you. Put both quotes against a finished roof, then stand in the yard and look at the elevation your family will see every day. At that point the question stops being a product debate and starts being a plan for your building.