EV Charger and Solar in Temecula: Why Installing Both at Once Saves You Money

Adrian Marin|Independent Solar Advisor, Temecula CA

Helping Riverside County homeowners navigate SCE rates and solar options since 2020

Installing a Level 2 EV charger alongside a new solar system is not just convenient. It saves on permits, cuts electrician costs, compresses the SCE interconnection timeline, and lets the EV charger qualify for the 30% federal solar tax credit. Here is the complete math for a Temecula homeowner adding a Tesla to their household.

How Much Electricity Does an EV Actually Add to Your Home?

Before getting to the money, it helps to understand the energy picture. A 2024 Tesla Model Y Long Range has an EPA-rated efficiency of approximately 3.5 miles per kWh, depending on driving conditions, speed, and climate. Temecula drivers typically see slightly lower real-world efficiency because of Interstate 15 highway driving and summer air conditioning load inside the vehicle.

At 15,000 miles per year driven at an effective efficiency of 3.5 miles per kWh, the Model Y consumes approximately 4,285 kWh annually, or roughly 357 kWh per month. For context, the average SCE residential customer in Riverside County uses approximately 700 to 900 kWh per month for their home. Adding a Model Y increases total household electricity consumption by 35% to 50%. That is not a rounding error. It is a meaningful load that needs to be planned for in your solar system size.

A shorter-range vehicle such as the standard Model 3 or a non-Tesla EV with a 150-mile range consumes proportionally less, typically 2,000 to 3,000 kWh annually at similar mileage. The numbers below use the Model Y as the reference because it represents a realistic mid-range case for Temecula households, where longer commutes and road trips to San Diego or Los Angeles are common.

Sizing Solar to Cover Both Your Home and Your EV

Temecula receives approximately 5.5 peak sun hours per day on average across the year, one of the better solar resources in Southern California. Each kilowatt of solar capacity in this region produces roughly 1,900 to 2,100 kWh per year after accounting for system losses, panel degradation in the first year, and seasonal variation.

A household that currently consumes 800 kWh per month (9,600 kWh per year) and wants to fully offset its bill with solar needs approximately 4.8 to 5.1 kW of solar capacity. Adding a Model Y at 4,285 kWh per year brings total annual household consumption to roughly 13,885 kWh. To cover that combined load, the system needs approximately 6.9 to 7.3 kW of solar capacity.

In practice, most installers recommend sizing to cover 100% to 110% of combined annual consumption when an EV is part of the plan. This provides a modest export buffer to ensure the system generates enough even in low-production months (December and January, when Temecula receives closer to 4.5 peak sun hours per day). For the household above, the recommended system size with a Model Y is approximately 7 to 7.5 kW.

The incremental cost of the extra panels to cover the EV is typically $2,500 to $4,000 for the additional 2 to 2.5 kW of capacity. That incremental cost qualifies for the 30% federal Investment Tax Credit the same as the rest of the system, bringing the net cost down to $1,750 to $2,800. Compared to paying SCE $50 to $80 per month to charge the car on the grid for years, the economics of sizing the solar system to cover the EV are very strong.

The Bundle Savings: One Permit, One Electrician, One Interconnection

The most underappreciated reason to install solar and an EV charger at the same time is the cost of doing them separately. When you combine both into a single project, you avoid duplicating three significant cost centers.

First, permits. A solar installation requires a building permit from the City of Temecula, Lake Elsinore, or the Riverside County Building Department, depending on your address. A Level 2 EV charger installation also requires an electrical permit. Each permit runs $200 to $500 in fees, plus the time and labor for the inspection. One combined project means one set of permits, one set of inspections, and one scheduled inspection visit from the building department.

Second, electrician labor. Both a solar installation and a Level 2 charger installation require electrical panel work, particularly when a panel upgrade is needed, which is common in older Temecula homes that have 100-amp service. Upgrading the panel once during a combined solar-and-charger installation costs $1,800 to $3,500 including labor. Doing it twice, first for solar and then returning for the charger, can cost $2,500 to $5,000 total because the electrician must return, resecure the panel, pull new wires, and schedule a second inspection. The combined project eliminates the second mobilization entirely.

Third, SCE interconnection. Every new solar installation in SCE territory requires an interconnection application, which is the process by which SCE reviews and approves your system for grid connection. Processing time for residential interconnection applications runs four to eight weeks. If you install the EV charger separately after the solar is already interconnected, there is no second interconnection required for the charger, since the charger does not connect to the grid directly. However, the charger circuit work can be folded into the initial inspection scope if done simultaneously, simplifying the sign-off process and reducing the number of separate inspection appointments needed.

Total savings from combining the installations into one project: typically $800 to $2,000 in hard cost savings, plus four to eight weeks of time savings on the project timeline.

The 30% Federal Tax Credit Covers the EV Charger When Bundled With Solar

Under Section 25D of the Internal Revenue Code, the 30% federal Investment Tax Credit applies to "qualified clean energy property," which includes solar panels, inverters, battery storage, and solar electric generating equipment. When an EV charging station (technically called Electric Vehicle Supply Equipment, or EVSE) is installed as part of a solar project, the IRS has consistently treated the charger equipment and its installation as part of the qualified clean energy system.

In practice, this means the cost of a Level 2 charger and its installation labor is included in the total project cost that you apply the 30% credit against. A $1,500 charger installation added to a $30,000 solar project brings the credit base to $31,500. At 30%, that is a $9,450 federal tax credit versus $9,000 for solar alone. The charger bundling generates an additional $450 in federal tax savings compared to claiming the charger separately.

The separate Section 30C alternative fuel vehicle refueling property credit, which applies to standalone EV charger installations, has different limits and phaseouts that make it less favorable in most cases. For homeowners adding a charger alongside solar, bundling into the Section 25D credit is almost always the better tax treatment.

The current 30% credit rate is scheduled to remain through 2032 under the Inflation Reduction Act. Verify current tax credit rules with your tax advisor, as your specific tax situation determines how much of the credit you can use in a given year.

Level 2 Charger Options: Tesla Wall Connector, ChargePoint Home Flex, and JuiceBox 40

Not all Level 2 chargers are equal, and the right choice for a Temecula home with solar depends on the vehicle, the monitoring priorities, and whether scheduled charging for TOU rate optimization matters.

The Tesla Wall Connector is the natural choice for Tesla owners. Running at 48 amps, it adds up to 44 miles of range per hour of charging. A Model Y with a 20% battery charge can reach 80% in under four hours overnight. The Wall Connector integrates natively with the Tesla app, which lets owners schedule charging, view energy consumed per session, and set off-peak charging windows automatically based on SCE rate schedules. Hardware cost: $400 to $500. Installation labor: $400 to $800 depending on panel work needed.

The ChargePoint Home Flex runs at up to 50 amps and is compatible with every EV on the market that uses a J1772 connector (which includes every non-Tesla, plus Tesla vehicles with an adapter). At 50 amps, it adds approximately 37 miles of range per hour. ChargePoint's app is highly regarded for energy monitoring: it breaks down energy consumption per session, tracks cost based on your utility rate, and supports smart scheduling for TOU rate optimization. Hardware cost: $550 to $700.

The JuiceBox 40 runs at 40 amps and adds approximately 30 miles of range per hour. It is specifically designed around smart grid integration. JuiceBox has a direct integration with SCE's rate schedule data, allowing automatic scheduling of charging during super off-peak windows without manual configuration. For homeowners who want set-it-and-forget-it TOU rate optimization, JuiceBox delivers that out of the box. Hardware cost: $400 to $650.

All three options charge a Model Y from 20% to 80% overnight well within a typical 8-hour sleeping window. The speed difference between 40 amps and 50 amps is meaningful only for larger battery packs (over 100 kWh) or for households where the car is not plugged in until late in the evening.

SCE TOU Rate Plans and the EV Charging Strategy

SCE's Time-of-Use pricing structure is the core of the solar-plus-EV financial case. Understanding the rate windows determines exactly when to charge the car, what to do with solar production during the day, and how a battery changes the calculus.

On the TOU-D-PRIME rate plan, which is the most common plan for new solar customers in SCE territory, the rate tiers work as follows in summer months: super off-peak (midnight to 9am) at approximately 12 to 14 cents per kWh, mid-peak (9am to 4pm and 9pm to midnight) at approximately 24 to 28 cents per kWh, and on-peak (4pm to 9pm) at approximately 47 to 55 cents per kWh during the highest-demand summer periods.

The charging strategy that maximizes savings is straightforward. Set the Level 2 charger to activate at midnight and complete by 6am. At 12 to 14 cents per kWh, charging a Model Y from 20% to 80% (approximately 50 kWh of energy added) costs $6.00 to $7.00. That covers roughly 175 miles of driving at a cost of 3.4 to 4.0 cents per mile. Compare that to a 30 mpg car at $4.70 per gallon in Temecula: 15.7 cents per mile for fuel alone.

During the day, your solar panels produce power at their peak. Some of that production offsets home daytime consumption (air conditioning, refrigerator, lighting). The remainder exports to the grid at the NEM 3.0 ACC rate of approximately 5 to 8 cents per kWh, which is lower than the off-peak import rate. This means it is almost always better to use midnight grid charging at 12 to 14 cents than to try to shift EV charging to daylight hours to use solar directly: you are essentially trading low-value exported solar for higher-value overnight super off-peak grid power.

The exception is when you have a battery. A Tesla Powerwall or Enphase IQ Battery absorbs excess solar production during the day at zero cost (you own the panels) and dispatches it in the evening to avoid the 4pm to 9pm on-peak window. If the battery has enough capacity after covering home evening load, it can also feed the EV charger after the on-peak window closes, effectively using stored solar at a cost of 0 cents per kWh rather than paying even the 12-cent super off-peak rate. The full efficiency stack of solar plus battery plus EV gets the effective cost of EV fuel to near zero.

The Full Efficiency Stack: Solar, Powerwall, and Model Y in Temecula

Let us put real numbers to the full stack for a Temecula homeowner with a 2024 Tesla Model Y.

Baseline situation: SCE bill of $280 per month (900 kWh at blended rate), plus $120 per month at the gas pump for a second vehicle being replaced by the Model Y. Total monthly energy and transportation fuel cost: $400.

After adding a 7.5 kW solar system sized for home plus EV, a Tesla Powerwall 3, and a Tesla Wall Connector, the monthly picture changes substantially. Solar production covers daytime home load directly. The Powerwall stores afternoon overproduction and dispatches it during the 4pm to 9pm on-peak window, eliminating most peak-hour grid purchases. The Model Y charges overnight at super off-peak rates or from stored solar, costing $15 to $25 per month in grid electricity versus $120 in gas.

Estimated monthly SCE bill after solar and battery: $20 to $60 for baseline service charges and any residual grid imports. Estimated monthly EV charging cost from grid: $15 to $25. Total monthly energy cost: $35 to $85, down from $400. Annual savings: $3,780 to $4,380.

Total project cost before incentives: 7.5 kW solar at approximately $3.00 per watt ($22,500) plus Powerwall 3 ($12,500 installed) plus Wall Connector with installation ($900). Total: $35,900. After 30% ITC on the full project ($10,770) and a potential SGIP rebate for the battery ($2,700 to $5,400): net project cost of $19,730 to $22,430.

At $4,000 in annual savings, payback from that net cost is approximately 5 to 5.6 years. The solar panels carry a 25-year production warranty. The Powerwall carries a 10-year warranty. The Wall Connector carries a 4-year warranty. All three components remain functional and productive well past payback.

Frequently Asked Questions