NEM 3.0 changed solar math.
If you have tile, do the roof first.

What changed with NEM 3.0 (and why payback got slower).

California's Net Energy Metering 3.0 framework (also called the Net Billing Tariff) took effect for new residential solar customers of PG&E, SCE, and SDG&E on April 15, 2023. It replaced NEM 2.0 for new installs. The single biggest change: the price the utility pays you for exported solar dropped roughly 75%, from a near-retail credit (~$0.30/kWh) to an “avoided cost” rate that averages closer to $0.05–$0.08/kWh.

That changes the optimal system design entirely. Under NEM 2.0, oversizing the array to push exports in summer and pull credits in winter was the play. Under NEM 3.0, the math says add a battery to capture your own solar during the day and self-consume it at night, when retail rates are highest.

Payback periods shifted with this change. A typical Central Valley home that would have hit payback in 6–8 years under NEM 2.0 now lands in the 10–13 year range under NEM 3.0 — sometimes longer without a battery. Which means: the roof under the solar array now has to last 25–30 years to make economic sense, not 18–20.

Why this matters more for tile roofs than for asphalt.

Asphalt-roof homeowners can replace the entire roof in a day or two if it fails after solar is installed. Tile is different. To re-roof a tile home with solar already mounted, you have to:

1. Pay the solar installer to disconnect, remove, and store the array (typically $3,000–$6,000 depending on system size)
2. Lift the tiles, replace the failing underlayment, and re-set the tiles ($12,000–$22,000 for the roof portion of the work)
3. Pay the solar installer to re-mount and reinterconnect the array ($3,000–$6,000)
4. Risk losing the solar manufacturer warranty if the original mounts are damaged during removal

Total surprise bill: $18,000–$34,000 in year 6 of a 10–13 year payback. That can flip the whole solar investment from “saved $200/month” to “net loss vs grid power.”

The fix isn’t complicated. If your tile roof is over 20 years old, replace the tile underlayment before the solar install. We call this a lift-and-relay: we carefully lift the existing tiles, tear off the worn felt underlayment, install a new synthetic high-temp underlayment, and re-set the same tiles. Cost: typically half a full tile replacement, since you keep the existing tile. The clock on the underlayment resets to year zero — another 25–30 years of service life before you’d need to do it again. See our tile roofing page for the full process.

How Tesla solar mounts on concrete and clay tile.

Tesla's residential solar panels (and Tesla’s installer partners like Sunlight Financial-network installers and Sunrun) mount on tile roofs using one of two industry-standard tile-hook systems:

• S-5! tile hooks — a flashed tile-replacement bracket that lifts a single tile, sits a metal flashing plate on the deck, and clips a hook upward through a precision-cut slot in the replacement tile. Properly installed, no penetration through the tile itself.
• Quick Mount PV tile hooks (QBase / QHook) — similar concept: the tile is lifted, a flashed deck plate is secured into the rafter, and a hook arm extends up to support the rail. Quick Mount has separate models for S-tile (curved profiles like Eagle Capistrano) and flat tile (like Boral concrete flats).

Both systems are compatible with the tile profiles we install most often: Eagle Capistrano (Spanish S-tile), Boral concrete flats (low profile), and the MCA / Westlake clay S-tiles. The mount selection depends on the tile shape and the solar installer’s standard kit — we coordinate directly with the solar contractor so the hooks land in the right rafter spacing and the deck flashing is correct.

What not to do: straight-through-the-tile mounts (a lag bolt driven through the tile into the rafter) cause tile cracking within 2–5 years from thermal cycling. We’ve replaced cracked tile fields under solar arrays where the original installer skipped the proper hook flashing. Don’t let any solar installer do that on your roof.

The right sequence: roof inspection → underlayment → solar.

Here’s the order we recommend for any tile-roof solar project, based on roofs we’ve walked over the past 30 years:

1. Free roof inspection first. Before you sign any solar contract, get a roofer up on the tile to assess underlayment age and tile condition. We’ll pull a couple of tiles, photograph the felt underneath, and give you a written report.
2. If underlayment is under 15 years old and in good shape: proceed to solar install directly. We coordinate with the solar installer on mount selection.
3. If underlayment is 15–25 years old or showing wear: lift-and-relay underlayment replacement first (~3–5 days). Then solar install, locked in for the next 25–30 years.
4. If underlayment is over 25 years old or actively failing: full tile replacement (or upgrade to a different roof material if you’re considering the change) before solar. Otherwise the math doesn’t work.
5. Solar install with proper tile-hook system. S-5! or Quick Mount tile hooks, deck-flashed, in correct rafter spacing.

We don’t sell solar. We work alongside the installer your project uses. Our job is to make sure the roof under the array is going to outlast the solar warranty.

Permits, interconnection, and the new NEM 3.0 paperwork.

A tile-roof solar project in Central Valley counties involves a few moving permit pieces:

• Building permit for the roof work (lift-and-relay or replacement) — pulled by us. Typical fee $150–$400. Inspection happens mid-install.
• Electrical permit for the solar install — pulled by the solar installer.
• Interconnection agreement with the utility (PG&E or SCE for our service area). Under NEM 3.0 this paperwork specifically uses the “Net Billing Tariff” framework, not the old NEM 2.0 net-metering agreement. The solar installer files this.
• Final inspection by the AHJ, then permission-to-operate (PTO) issued by the utility. Typical from contract-signed to PTO: 8–14 weeks in 2026.

Doing the roof first adds 3–7 days to the schedule but doesn’t delay the solar interconnection meaningfully — the long pole is the utility’s PTO queue, not the roofing schedule. Plan ahead and the sequence is clean.

Battery sizing under NEM 3.0 — quick framing.

We’re not battery installers, but we’ve been on enough coordinated jobs to share the framing solar installers use post-NEM 3.0:

• Without a battery: NEM 3.0 payback typically lands 12–15 years because so much of your exported solar earns the low avoided-cost rate.
• With a 10–13.5 kWh battery (Tesla Powerwall 3, Enphase IQ Battery 5P): payback drops to 8–11 years because you self-consume more solar at peak retail rates.
• Battery oversizing past 20 kWh: diminishing returns for most Central Valley homes. The marginal kWh of storage doesn’t get filled often enough to justify the cost.

Your solar installer will model your specific bill against utility rate schedules (PG&E E-ELEC for example) to pick the right battery size. We just make sure the roof is sound and ready before they install.

Cost reality — tile roof + solar coordinated project.

Typical Central Valley tile-roof home (2,000–2,500 sq ft) doing a coordinated roof + solar project in 2026:

• Tile lift-and-relay (underlayment replacement, same tiles): $14,000–$22,000
• Full tile replacement (if tiles broken or upgrading): $25,000–$50,000
• 8–10 kW solar array (panels + inverter + install): $24,000–$36,000 before federal incentives
• 10–13.5 kWh battery: $12,000–$18,000 installed
• Federal Investment Tax Credit (30% through 2032): applies to solar + battery costs

Doing the roof underlayment first adds $14K–$22K to the project but eliminates the $18K–$34K surprise bill in year 6. The math favors doing it right the first time, especially under NEM 3.0’s longer payback window. Financing is available for the roofing portion if you’re bundling.

Common questions

Frequently asked.

Tile roof + solar project on the table?

Free inspection, written assessment of whether the roof is solar-ready, and a coordinated roof + solar quote so the timing works. We've installed solar on concrete and clay tile across the Central Valley since 2017.