A Complete 2026 Guide to Solar System Sizing in Fresno
Choosing the right solar system size is one of the most important steps when designing a project in Fresno. An undersized system forces homeowners to buy expensive grid electricity all year long. An oversized system adds unnecessary cost. The goal is always the same: size the system accurately so it offsets your usage, supports your battery correctly under NEM 3.0, and provides the lowest long term energy cost.
This guide breaks down exactly how Supreme Solar and Electric sizes solar and battery systems in Fresno using real usage patterns, real production data, and a design strategy that keeps grid usage under 5 percent.
1. Start with Your Annual Electricity Usage
Before looking at panels or batteries, the first question is always:
How much power does the home use in a full 12-month cycle?
Most homeowners fall into one of two categories:
A. You have at least 12 months of usage
Perfect. Supreme Solar and Electric uses your actual consumption to determine how much solar you need.
B. You do NOT have 12 months of usage
This is extremely common. In that case, system sizing is based on:
- Home square footage
- Number of occupants
- Appliances
- Pools or spas
- EV charging
- Lifestyle habits
- Past owner data (if available)
The goal is always accuracy, not guessing.
2. Identify All Future Add-Ons That Increase Usage
Accurate solar sizing in 2026 must include your future electricity needs, not only your current ones. Here are the most important usage add-ons Supreme Solar and Electric accounts for:
- Electric Vehicles: Charging an EV at home adds 3,000 to 5,000 kilowatt hours per year, depending on commute and battery size.
- Pools and Spas: Typical pool equipment adds 1,500 to 2,500 kilowatt hours annually. Heat pumps and hot tubs add even more.
- Switching From Gas to Electric Appliances
- These upgrades significantly change your consumption:
Electric water heater: +1,200 kilowatt hours per year
Electric oven: +300 to 400 per year
Electric dryer: +600 per year - Heat pump HVAC conversion: often thousands of additional kilowatt hours
- Space Heaters and Plug in Heating: These are extremely electricity intensive. Even a small space heater running daily becomes a major load.
- Lifestyle Changes: Most homeowners dramatically increase their usage after going solar because electricity finally becomes affordable. This alone is enough to make a system undersized if the calculation is not adjusted.
Supreme Solar and Electric always builds this into the design.
3. Target 120 to 130 Percent Offset for NEM 3.0
Under today’s net billing structure, credits are low, and batteries are required to capture excess solar and use it at night. Because of this, the old 100 percent offset model does not work well. The modern strategy is: 120 to 130 percent annual offset, which accounts for:
- Summer AC loads doubling or tripling usage
- Lower winter solar production
- Evening usage that must come from a battery
- Lifestyle increases
- EV charging
- Appliance upgrades
This is especially important in Fresno where:
- Summers are long and hot
- AC runs heavy for months
- PG&E electricity prices are extremely high
A correctly sized system paired with a properly sized battery keeps grid usage below 5 percent.
4. Understand Fresno’s Solar Yield
Fresno is one of the strongest solar production zones in the United States.
On average, Fresno produces about 1,550 kilowatt hours per kilowatt of solar installed each year. This is outstanding and one of the main reasons the ROI is so strong in the Central Valley.
The most beneficial roof orientations:
- South
- West
- East
(North-facing roofs are avoided whenever possible because production drops heavily in winter.)
Shade evaluation matters. Trees, chimneys, second story walls, and neighboring homes all impact yield. Supreme Solar and Electric evaluates this carefully to keep your sizing accurate.
5. The Supreme Solar and Electric Formula
Here is the real calculation used for Fresno system design:
STEP 1: Start with annual usage
Example:
10,000 kilowatt hours per year.
Example future add ons:
- EV charging: +4,000
- Pool pump: +1,800
- Lifestyle increases: +1,000
New total: 16,800 kilowatt hours per year
STEP 3: Multiply by 1.2 to 1.3 for ideal offset
16,800 × 1.25 = 21,000 kilowatt hours needed from solar
STEP 4: Divide by Fresno’s solar yield
21,000 ÷ 1,550 = 13.5 kilowatts of solar
So, the home needs around a 13.5-kilowatt system, typically 26 to 30 panels.
This is the same calculation Supreme Solar and Electric follows in every project.
6. How Battery Size Fits into the Equation
Even though the question is, “What size solar system do I need?”, proper system design in 2026 always includes a battery.
A battery that is too small will leave you buying power at the most expensive times of day.
The correct battery sizing formula is: 2.5 to 3 kilowatt hours of usable battery storage per 1 kilowatt of solar
For Example: 13.5 kilowatt solar → 33 to 40 kilowatt hours of usable storage
This ensures:
- Less than 5 percent grid usage
- True nighttime coverage
- Excellent summer performance
- Protection during outages
Supreme Solar and Electric sizes every battery using this same method.
7. Fresno Homes Often Need Slightly Larger Systems
Why?
- AC loads are extremely high in summer
- Production dips in winter months
- Homes typically increase usage after going solar
- PG&E rates are among the highest in the nation
- Battery performance depends on having enough daytime overproduction
Larger systems create better ROI, better battery behavior, and lower long term power costs.
8. Realistic System Size Examples
- Small homes (1,500 to 1,800 sq ft)
Usage: 8,000 to 10,000 kilowatt hours
System: 8 to 10 kilowatts - Medium homes (2,000 to 2,400 sq ft)
Usage: 12,000 to 15,000 kilowatt hours
System: 12 to 15 kilowatts - Large homes (2,800 to 4,000 sq ft)
Usage: 18,000 to 26,000 kilowatt hours
System: 18 to 26 kilowatts
9. The Risk of Undersizing Your Solar Battery
Undersized systems are the number one reason homeowners still have large electric bills after installing solar.
This usually happens because:
- The homeowner increased usage after installation
- An EV or pool was added later
- Designer did not use the 120 to 130 percent offset model
- Battery was undersized
- The installer did not account for shading or roof orientation
Supreme Solar and Electric prevents this by running multiple production simulations and building for long term accuracy.
10. Summary: The Fresno Solar Sizing Formula
To size your system correctly:
- Gather 12 months of usage
- Add future consumption
- Multiply by 1.2 to 1.3
- Divide by Fresno’s 1,550 yield
- Size battery at 2.5 to 3 kilowatt hours per 1 kilowatt of solar
This formula consistently produces the right offset and the right battery sizing under NEM 3.0.
Need Help Calculating Your Exact System Size?
Solar sizing is not guesswork. Roof pitch, shading, tilt, future appliances, EV charging, lifestyle habits, and battery behavior all play major roles in designing a system that performs the way it should. Supreme Solar and Electric has designed and installed thousands of systems across Fresno and the Coachella Valley using this exact methodology.
If you want a personalized solar and battery model built using your home’s actual data, our team can:
- Analyze your roof
- Review 12 months of usage
- Project future consumption
- Run a full NEM 3.0 battery simulation
- Build a custom system design with real production numbers
- A properly sized system is the difference between cutting your bill in half and still being stuck with expensive PG&E charges.
Supreme Solar and Electric can help you get it right from day one.