California Solar Questions Answered: 30+ Technical FAQ for Homeowners

How long do solar panels last?

Modern monocrystalline solar panels are warrantied for 25–30 years and typically operate well past 30 years at gradually reduced output. Industry standard performance degradation is 0.4–0.5% per year, meaning a 25-year-old panel still produces about 87–90% of its original output. Panels rarely fail outright; they fade. Inverters typically last 12–15 years and need replacement once during the panel lifetime, costing roughly $2,000–$4,000.

Do I need a battery with solar in California in 2026?

Under NEM 3.0 (the rule for all new California interconnections since April 14, 2023), batteries are practically essential for the system to make economic sense. NEM 3.0 pays you about $0.05–$0.10/kWh for energy you export to the grid (Avoided Cost Calculator rate) but charges you $0.40–$0.55/kWh to buy that same energy back during peak hours. Storage lets you use your own production at peak rates instead of selling at wholesale and rebuying at retail. Solar without storage on NEM 3.0 leaves significant value on the table.

NEM 2.0 customers (interconnected before April 14, 2023) can run solar-only and still get full retail credit on exports.

Can I get solar without a battery in California?

Yes, but the math is dramatically worse than solar-with-battery under NEM 3.0. A solar-only system on NEM 3.0 typically pays back in 12–15 years instead of 7–10 with a battery. Some installers will sell solar-only because the system cost is lower, but the customer’s lifetime savings are also lower. If your installer recommends solar-only on NEM 3.0 without explaining the trade-off, get a second opinion.

What is the difference between NEM 2.0 and NEM 3.0?

NEM 2.0 (Net Energy Metering) credits exported solar energy at full retail rates ($0.30–$0.55/kWh in California). NEM 3.0 credits exported energy at the Avoided Cost Calculator rate ($0.05–$0.10/kWh, about 25% of retail). Under NEM 2.0, exporting was profitable; under NEM 3.0, self-consumption with batteries is profitable and exporting is value-loss. NEM 2.0 applies to systems interconnected before April 14, 2023; NEM 3.0 applies to all new interconnections after that date. The change forced a structural shift in how solar systems are designed.

Will my solar panels work during a power outage?

Solar panels alone do not work during a grid outage, even though they are producing power. Standard grid-tied solar systems are required by safety code to shut down during an outage so utility line workers are not exposed to backfed power. To run loads from solar during an outage, you need a battery system with islanding capability (Powerwall, Enphase IQ Battery, etc.). With batteries, your system disconnects from the grid during an outage, runs your home from stored solar, and re-syncs when grid power returns.

How much do solar panels cost in California?

Residential solar in California costs about $3.00–$4.50 per watt installed, depending on system size, financing, panel quality, and battery configuration. A typical 7 kW system runs $21,000–$32,000 before any financing structure. Adding two Tesla Powerwall 3 batteries adds about $25,000–$30,000. Total all-in for a 7–10 kW system with two batteries: $50,000–$70,000 purchase price, or equivalent in PPA monthly payments. Prepaid PPA structures often run lower than purchase because the installer claims commercial tax credits internally.

Can I claim the federal solar tax credit in 2026?

No. The federal Residential Clean Energy Credit (Section 25D) terminated for systems placed in service after December 31, 2025, under the One Big Beautiful Bill Act (OBBBA) signed July 4, 2025. Homeowners purchasing solar in 2026 cannot claim the 30% federal credit. Sunrun-owned PPA paths (monthly or prepaid) use a separate commercial credit Sunrun claims internally; their pricing reflects whatever credit they receive, but it is not a credit the homeowner files. California’s property tax exclusion under Rev. & Tax Code §73 still applies through January 1, 2027 — solar systems do not increase the property’s assessed value.

Do solar panels increase home value?

Owned solar systems typically add $15,000–$25,000 to a home’s resale value, according to Lawrence Berkeley National Laboratory and Zillow studies. PPA-financed and leased systems generally do not add resale value because the buyer assumes a contract obligation. The added value depends on system size, age, and whether the new buyer wants to assume a PPA. Owned-system pricing premium is most pronounced in higher-electricity-rate states (California qualifies) and on homes that already have higher resale values.

What happens to solar if I sell my house?

If you own the system, it transfers with the property and typically adds resale value. If you have a PPA or lease, the agreement transfers to the new buyer, who assumes the monthly payment. Sunrun’s PPA includes a service transfer guarantee. Most buyers welcome a paid-up prepaid PPA (free electricity for the remaining contract years) but may push back on a high-payment monthly PPA. The transferability is a contractual term — review your specific agreement before listing the home.

Will my HOA allow solar panels in California?

California’s Solar Rights Act (Civil Code §714) prohibits HOAs from unreasonably restricting solar installations. HOAs can require aesthetic reviews and ensure code compliance, but cannot ban solar outright or impose restrictions that would substantially reduce system performance or significantly increase cost. Aesthetic guidelines (color of mounting hardware, panel placement on less-visible roof faces) are generally allowed; outright prohibition is not. If your HOA blocks solar, the Solar Rights Act gives you legal standing to install anyway.

How long does solar installation take?

From contract signing to system activation, the typical timeline is 8–16 weeks. Breakdown: design and permits take 4–8 weeks, equipment ordering and delivery 2–4 weeks, physical installation 1–3 days, inspection 1–2 weeks, PG&E permission to operate (PTO) 2–6 weeks. Ground-mount systems add 4–8 weeks for foundation work and trenching. The longest delays usually come from city/county permit review and PG&E PTO, neither of which the installer fully controls.

What is the difference between Powerwall 2 and Powerwall 3?

Tesla Powerwall 3 (released 2024) is a fundamentally different design from Powerwall 2. Key differences: Powerwall 3 has a built-in solar inverter (eliminating the need for a separate string inverter), supports up to 20 kW solar input, has 11.5 kW continuous AC output (up from 7 kW), and has 13.5 kWh capacity. Powerwall 2 was AC-coupled and required a separate inverter. Powerwall 3 is DC-coupled which is more efficient. New installations almost universally use Powerwall 3 now.

How many solar panels do I need?

The right number depends on your annual usage, available roof or ground space, and whether you have NEM 2.0 or NEM 3.0. Rough math: divide your annual kWh usage by typical per-panel production for your area (about 500–700 kWh/panel/year in El Dorado County for unshaded south-facing panels). A 14,000 kWh/year household typically needs 22–28 panels (10–13 kW). Under NEM 3.0, sizing closer to 100% of consumption is more economic than oversizing.

Do solar panels work in cloudy weather?

Yes, but at reduced output. Heavy overcast typically drops production to 10–25% of peak. Light overcast drops production by 30–50%. Bright haze actually sometimes increases production via diffuse light scattering. Annual production estimates already account for typical California cloud patterns — El Dorado County’s annual sun-hours figure reflects actual weather, not idealized clear-sky.

Do solar panels work in snow?

Solar panels are tested for snow loads and perform fine in snowy conditions. Snow on top of panels temporarily blocks production, but most snow slides off panels within a day or two on typical roof pitches. Total annual snow-related production loss in El Dorado County, where light snow happens occasionally, is well under 5% — already factored into production estimates.

How do I clean solar panels?

Most California solar panels need minimal cleaning. Rain handles 90% of dust/pollen accumulation. For homes near agricultural fields, dirt roads, or with heavy bird activity, a quarterly hose-down with a soft brush handles the rest. Avoid pressure washers and abrasive cleaners — they can damage anti-reflective coating. Professional cleaning runs $150–$300 per visit but typically isn’t needed more than once a year.

What if my solar system underperforms?

Sunrun’s PPA and lease products include a 25-year production guarantee — if the system produces less than projected, you receive a credit for the shortfall. Owned systems have manufacturer warranties on panels (25–30 years for output below specification) and inverters (10–15 years). Production monitoring is built into modern systems; the installer (or you) gets alerts when output drops. Most underperformance is fixable — bad inverter, dirty panels, growing tree shade.

Can I add panels to my solar system later?

Yes, but expansion has rules. Under NEM 2.0, expanding a system within 110% of original sizing typically preserves NEM 2.0 status; expanding beyond that triggers transition to NEM 3.0 for the whole system. Battery additions to existing solar can preserve NEM 2.0 in some configurations. Adding panels usually requires inverter upgrades to handle the additional capacity. The cleanest path is right-sizing the original system; expansion is workable but more expensive per panel than the original install.

What is the difference between leasing and PPA?

A solar lease is a fixed monthly payment for use of the equipment, regardless of how much energy it produces. A Power Purchase Agreement (PPA) is a payment per kWh produced, so your monthly bill scales with production. PPAs can be monthly (with annual escalator, typically 3.5%) or prepaid (lump sum upfront, locked rate, no escalator). Sunrun’s main residential offerings in California are monthly PPA and prepaid PPA.

Can I buy solar outright instead of using PPA?

Yes — purchase or loan-financed ownership is an option through most installers. Pros: you own the asset, it adds home resale value. Cons: higher upfront cost, you handle maintenance and any unexpected repairs after warranty, you replace the inverter at year 12–15 ($2–4K). PPA pros: no money down, all maintenance and warranty issues are the installer’s problem, locked production guarantee. The right answer depends on your tax situation, cash availability, and how long you plan to be in the home.

What is the California Solar Consumer Protection Guide?

The California Solar Consumer Protection Guide is a CPUC and CSLB publication required to be provided to every California solar customer before they sign a contract. It covers required disclosures, the right to cancel within three business days, how to verify installer licenses, complaint and warranty resolution processes, and key terms to look for in a solar agreement. Reputable installers provide a copy automatically; you can also download it from the CPUC website. Read it before signing anything.

How do I verify a solar installer is licensed in California?

California requires solar installers to hold an active CSLB (Contractors State License Board) license, typically C-46 (Solar) or C-10 (Electrical). Verify any installer at cslb.ca.gov by entering their license number. Confirm: license is active, no disciplinary actions, bond is current, workers’ compensation insurance is current. Salespeople (not installers) need a Home Improvement Salesperson (HIS) license — verify the same way. Anyone selling or installing solar in California without a license is operating illegally.

Will solar work for my house?

Solar typically works well if you have: usable south-, west-, or east-facing roof space (or yard space for ground-mount); minimal heavy shade in the 9 AM–4 PM solar window; annual electric usage above 5,000 kWh per year; plans to be in the home for 7+ years.

Solar may not pencil if: heavy tree shade is unavoidable, roof needs major work in the next 5 years, usage is very low (under 4,000 kWh/year), you plan to move within 3 years, or you don’t own the property.

What roof material is best for solar?

Asphalt shingle, concrete tile, and standing-seam metal all work well for solar. Asphalt is the easiest and cheapest install. Tile requires special mounting hardware (more expensive but doable). Standing-seam metal uses non-penetrating clamps which is technically the best mount but limited to that specific roof type. Wood shake is the most problematic; some installers won’t work with it. Roof age matters more than material — if your roof has under 10 years of life left, replace it before adding solar.

Can solar panels survive hail?

Modern solar panels are tested to UL 61730 and IEC 61215 standards, including impact resistance up to 1-inch hail at 50 mph. Real-world hail damage to panels in California is rare. Most homeowners insurance covers solar panels under the dwelling policy or as a scheduled item; verify with your insurer before installation. PPA-owned systems are insured by the installer.

Do solar panels need permits?

Yes. Every California residential solar installation requires building and electrical permits from the local jurisdiction (city or county). For El Dorado County addresses, that’s the El Dorado County Building Department. Your installer pulls the permits, schedules the inspection, and handles utility interconnection. Permit fees are typically $300–$1,200 depending on system size and jurisdiction; this is included in your installer’s quoted price.

What is a smart panel and do I need one?

A smart panel (SPAN, Schneider, Lumin, etc.) replaces or supplements your home’s main electrical panel and provides circuit-level monitoring and control. Practical benefits: see exactly which circuits are using power in real-time, automatically shed non-essential loads during outages or peak hours, schedule EV charging or pool pump runs to align with solar production. Cost: $3,500–$6,000 installed. Worth it if you have an EV, pool, or want active load management. Not strictly required for solar to work; nice-to-have for NEM 3.0 self-consumption optimization.

How does net metering true-up work?

Once per 12-month cycle, PG&E reconciles your solar system’s net consumption. Throughout the year, you bank credits for excess production and apply them against months you consumed more than you produced. At true-up: any net consumption is billed at retail rates; any net production under NEM 2.0 is paid at the wholesale Net Surplus Compensation rate ($0.03–$0.05/kWh); under NEM 3.0, excess credits are typically forfeited. Your true-up date is set when you interconnected.

Can I run my whole house on solar and battery?

Almost — depending on system size, weather, and household behavior. A correctly sized system with sufficient battery storage can cover 90–100% of annual consumption, with the grid as backup for unusual demand or extended cloudy periods. Going truly off-grid (zero PG&E connection) requires significantly larger battery storage and is usually impractical from a cost standpoint. Most California solar customers stay grid-tied with batteries, treating PG&E as a backup utility for the 5–10% of the year they need it.

What happens to solar at the end of the 25-year contract?

For PPA and lease customers, the contract end gives several options: renew the agreement for additional years (typically at lower rates); buy the system at fair market value (often surprisingly low after 25 years); or have the installer remove the system at no cost. Sunrun’s PPA includes a 25-year end-of-term system removal guarantee. For owned systems, the panels typically still produce 85–90% of original output and continue functioning past 30 years.

What is a production guarantee?

A production guarantee is a contractual commitment by the installer that the system will produce at least a specified amount of energy each year (usually 90–95% of projected). If the system underproduces, the installer credits the customer for the shortfall (under PPA, that’s a reduction in monthly payment; under purchase, it’s a cash payment or repair to fix the underperformance). Sunrun’s PPA and lease products include a 25-year production guarantee. Always read the specific terms.