How to Calculate the Return on Investment (ROI) for Solar Panels
Is Solar Actually Worth It?
If you’re considering solar, you’ve probably asked the big question: “Is this really worth it?”
The clearest way to answer that is by looking at return on investment—your ROI.
But here’s the part many people miss: solar isn’t just about saving money today. It’s also about protecting yourself from rising energy costs in the future. While utility rates tend to go up over time, solar helps lock in a portion of your energy costs.
In this guide, we’ll walk you through how to calculate your solar ROI step by step—so you can evaluate it with confidence.
What “ROI” Means for Solar
In simple terms, ROI compares how much money you gain versus how much you spend.
For solar, that means:
· What you pay for the system
· What you save on electricity over time
Solar works a little differently than most investments:
· It delivers long-term savings, not quick returns
· It creates predictable energy costs
· It helps protect against rising utility rates
So instead of thinking in months or even a few years, solar ROI is best understood over decades.
The Basic ROI Formula (Simplified)
Here’s a simple way to calculate solar ROI:
ROI = (Total Savings Over Time – System Cost) ÷ System Cost
Let’s break that down:
· System Cost = What you pay to install solar
· Total Savings Over Time = What you don’t pay your utility company over the life of the system
Step-by-Step: How to Calculate Your Solar ROI
Step 1: Determine System Cost
Most residential solar systems fall somewhere between:
· $20,000 to $35,000, depending on size and home energy needs
Step 2: Estimate Annual Energy Savings
Start with your current electric bill.
Example:
· $125/month = $1,500/year
A typical system may offset:
· 80% to 100% of your electricity use
Step 3: Estimate System Lifespan
Most systems last:
· 25 to 30 years
For conservative calculations, use 25 years.
Step 4: Calculate Total Savings (Baseline)
Multiply:
· Annual savings × years of use
This gives you a simple starting point—but it assumes electricity prices never change.
Accounting for Rising Electricity Costs
Electricity rates rarely stay flat. Historically, many regions have seen increases of 5% to 10% per year. When you account for that, solar savings grow significantly over time.
Here’s a simplified way to estimate that impact:
Step 4A: Adjust Savings for Annual Rate Increases
Instead of assuming your $1,500/year stays constant, you increase it each year.
For example (5% increase):
· Year 1: $1,500
· Year 2: $1,575
· Year 3: $1,654
· Year 10: ~$2,443
· Year 25: ~$5,080
At a 10% increase:
· Year 10: ~$3,891
· Year 25: ~$16,250
What This Means
Over 25 years:
· Flat-rate estimate: $37,500
· 5% increase scenario: ~$71,000+
· 10% increase scenario: $120,000+
That’s a major difference—and it helps explain why solar often performs better than initial estimates.
Simple Rule of Thumb
If you want a quick estimate without complex math:
· Multiply your baseline savings by 1.5 to 3× to reflect long-term rate increases
This keeps your projection realistic without overcomplicating things.
Step 5: Apply the ROI Formula
Now plug your numbers into the formula:
ROI = (Total Savings – System Cost) ÷ System Cost
Example Scenario (With and Without Rate Increases)
Baseline (No Rate Increase):
· System cost: $25,000
· Annual savings: $1,500
· Total savings: $37,500
· ROI: 50%
With 5% Rate Increases:
· Total savings: ~$71,000
· ROI: ~184%
With 10% Rate Increases:
· Total savings: $120,000+
· ROI: 300%+
What About Payback Period?
Baseline:
· $25,000 ÷ $1,500 ≈ 16–17 years
With rising rates:
· Payback often shortens by several years
Because your savings increase each year, you recover your investment faster than a flat estimate suggests.
Download our Solar ROI Quick Sheet.
Factors That Affect Solar ROI
Electricity Rates
Higher rates = higher savings
Rising rates amplify long-term returns.
Sun Exposure and Roof Orientation
More sunlight = more production and savings
System Size
Larger systems offset more energy but cost more upfront
Utility Rate Increases
One of the biggest drivers of long-term ROI
Financing vs. Cash Purchase
Payment structure affects timing and overall return
Payback Period (Quick Overview)
Your payback period is how long it takes for savings to equal system cost.
After that:
· Your system is producing effectively free electricity
· And rising rates increase that value over time
Why ROI Isn’t the Only Benefit
Solar also provides:
· Protection from rising utility rates
· Predictable monthly costs
· Greater energy independence
· Potential increase in home value
Final Thoughts
Now you know how to calculate solar ROI—and how to make that estimate more realistic by factoring in rising electricity costs.
That one adjustment can significantly change how solar performs financially over time.
If you ever want help running the numbers based on your home and energy usage, we’re here to help.
Frequently Asked Questions
What is a good ROI for solar panels?
A positive ROI over 25–30 years is considered good. Many homeowners see 30%–60% returns at baseline, often much higher when accounting for rising rates.
How long does it take for solar panels to pay for themselves?
Typically 10 to 18 years, often shorter when electricity prices increase over time.
Do solar savings increase over time?
Yes. As utility rates rise, your savings increase each year.
Is solar still worth it if I don’t stay long-term?
It can be. Solar may increase home value and buyer appeal.
What’s the biggest factor in solar ROI?
Electricity rates—especially how they change over time.