Adding a luxury electric vehicle — a Rivian R1S, Porsche Taycan, Tesla Model X, or Mercedes EQS — to your garage fundamentally changes your home’s energy profile. A standard Level 2 home charger pulls 7.2 to 11.5 kW of continuous power, which is comparable to running an entire central air conditioning system. If you have two EVs charging simultaneously, you’ve effectively doubled your home’s peak electrical load.
If you simply plug these vehicles into your home without an energy strategy, your PG&E bill will skyrocket. The irony is painful: you bought an electric vehicle to eliminate fuel costs, and instead you’ve transferred them — and then some — to your electric bill.
Understanding the load impact
A typical California home consumes 20 to 30 kWh of electricity per day. A single EV driven 40 miles per day (the average American commute) adds roughly 12 to 15 kWh of daily consumption. That’s a 40 to 60 percent increase in your home’s total energy use — from one vehicle.
For households with two EVs, or families who drive more than average (school runs, weekend trips, longer commutes), the additional load can exceed the home’s baseline consumption entirely. Without solar to offset this new demand, the utility bill impact is dramatic.
Smart charging integration
When we design residential solar systems for EV owners, we don’t just look at past utility bills. We model future energy consumption based on the vehicles you own (or plan to buy), your driving patterns, and your charging preferences.
The smart charging approach
We program the home’s smart energy hub to ensure your vehicles charge primarily when the sun is shining and solar production is highest, or when utility rates are at their absolute lowest (typically midnight to 6:00 AM). The system coordinates EV charging with battery state-of-charge, household loads, and solar production in real time — automatically adjusting the charging rate to optimize economics without any manual intervention.
Sizing for the future
One of the most common mistakes we see in residential solar design is sizing the system for today’s loads without accounting for the EV that’s arriving next year. A solar array sized for a 25 kWh/day household will be woefully undersized once two EVs add 25 kWh of daily charging demand.
We always ask homeowners about their vehicle plans for the next three to five years. It’s far more cost-effective to install a slightly larger solar array now than to retrofit additional panels later. The marginal cost of adding capacity during the initial installation is a fraction of what a separate return visit costs.
The panel-to-wheel economics
When your EV charges from your own solar panels, the effective cost per mile drops to roughly $0.03 to $0.04 — compared to $0.08 to $0.12 per mile charging from the grid at peak rates, and $0.12 to $0.18 per mile for a comparable gasoline vehicle. Over 15,000 miles per year, that’s $1,200 to $2,000 in annual fuel savings per vehicle. Multiply that by two vehicles and a 15-year system life, and the solar array is paying for a significant portion of itself through fuel cost elimination alone.
Driving an EV should eliminate your fuel costs, not transfer them to your electric bill. The right energy system ensures that’s exactly what happens.