Solar ROI Calculator

Find out how long it could take for your solar system to pay for itself and how much you could save on electricity over time.

Enter your planned solar system size, installation cost, monthly electricity consumption, electricity tariff, average sunshine hours and system efficiency to estimate your total investment, solar output, annual savings, payback period and simple annual ROI.

Your results are estimates based on the information you enter. Actual savings may vary with changes in solar production, electricity rates, equipment performance, maintenance, installation quality, and electricity consumption.

What does the solar ROI calculator show?

The calculator gives you several financial and energy figures. Understanding each will help you compare solar options more effectively.

Total cost of solar system

The system cost is calculated from the solar capacity and installed cost per watt that you enter.

The formula is:

System cost = System size (kW) × 1,000 × Cost per watt

For example, if you enter a 10 kW system at PKR 135 per watt:

10 × 1,000 × 135 = PKR 1,350,000

For a more accurate comparison, use the installed cost from a recent solar quotation rather than an old or typical market price.

Monthly solar production

Monthly solar production is an estimate of how much electricity your chosen system can generate based on the hours of sunshine and the efficiency of the system you enter. The actual race can change due to:

•  Weather
•  Weather conditions
•  Roof orientation
•  Panel tilt
•  Shading
•  Temperature
•  Dust
•  Equipment performance
•  Installation quality

Monthly and annual solar savings

This figure estimates the financial value of solar electricity generated under the values you entered. The actual reduction in your electricity bill may vary as the cost of electricity may depend on whether it is used directly on the property, imported from the grid or exported.

Solar power systems offer benefits beyond just electricity savings. By generating renewable energy and reducing reliance on grid electricity, they can also help lower the environmental impact associated with energy consumption. You can use our solar carbon footprint calculator to estimate the potential environmental impact of switching to solar energy.

Solar energy payback period

The payback period is estimated by how long it may take for your accumulated electricity savings to equal the initial cost of the solar system.

The basic formula is:

Payback period = Total system cost ÷ Annual savings

For example, if a solar system costs PKR 1,200,000 and saves an estimated PKR 300,000 per year :

1,200,000 ÷ 300,000 = 4 years

Lower installation costs or higher annual savings typically result in a shorter payback period.

Simple Annual Solar ROI

Simple annual ROI compares your estimated annual savings to the actual cost of the system.

The formula is:

Simple Annual ROI (%) = Annual Savings ÷ Total System Cost × 100

For example:

System Cost: PKR 1,000,000
Estimated Annual Savings: PKR 200,000

The calculation is:

200,000 ÷ 1,000,000 × 100 = 20%

In this example, the estimated annual savings equal 20% of the initial system cost. This is a simple calculation of ROI. It is different from the internal rate of return (IRR), which requires a detailed analysis of year-over-year cash flows.

Electricity usage coverage

Usage coverage compares the estimated solar output to the monthly electricity consumption you enter. It shows how much of your electricity needs can be generated by solar energy. This percentage may not match the percentage reduction in your electricity bill. The monetary values of electricity used directly, purchased from the grid, and exported to the grid may be different.

Estimated 25 years of savings

The 25-year result shows how solar savings can accumulate over the long term.

Over such a long period, actual results may be affected by changes in:

•  Electricity prices.
•  Solar panel performance
•  Care requirements
•  Equipment replacement
•  Power consumption
•  Grid rules

The figure represents estimated total savings, including the value of solar electricity used directly and electricity exported to the grid. It should not be expressed as a net present value (NPV) unless future cash flows are discounted to their present value.

Year-over-year solar savings

The annual breakdown estimate shows annual savings and overall savings over time. This can also help you see when the accumulated savings reach the actual cost of the system. Instead of focusing on an individual upcoming year, use the table to understand how savings can build up over the life of the system.

How to use the Solar ROI Calculator?

1. Enter the size of your solar system.

Enter your planned solar capacity in kilowatts (kW).

If you don’t yet know the capacity you need, calculate it first using the solar size calculator .

2. Enter your installed cost per watt.

Enter the total installed cost per watt for the solar system you are considering.

If you already have a quotation, use that price instead of a general market estimate.

Check what’s included in your solar quote:

Your quote may include:

•  Solar panels
•  Inverter
•  Mounting structure
•  Wiring
•  Electrical protection
•  Installation labor
•  Application or approval work
•  Other installation components

Compare quotations on the same scope before using cost per watt as a basis for ROI comparison.

3. Enter your monthly electricity consumption.

Enter your monthly electricity consumption in kWh or units. If your consumption changes significantly between summer and winter, use an average over several months instead of an unusually high or low bill. Reviewing your usage over the course of a full year can give you a clearer picture of your overall electricity usage.

4. Enter your electricity tariff.

Enter the electricity rate in PKR per kWh that applies to your calculation. Use a recent electricity bill where possible as tariffs may change over time.

5. Enter the average daily sunshine hours.

Enter realistic peak sun times for your location. Peak sun hours are not the same as the total number of daylight hours. They represent the equivalent duration of strong solar radiation used when estimating solar energy production.

6. Enter system performance.

The performance setting shows the difference between ideal panel output and real-world system performance.

Common sources of solar system damage

Damages can occur from:

•  High panel temperature
•  Inverter replacement
•  Wiring
•  Dust and dirt
•  Shading
•  Equipment performance

Using a realistic performance value gives you more meaningful production and ROI estimates.

7. Calculate your solar ROI.

Run the calculator and review the full set of results.

Pay special attention to:

•  Total system cost
•  Monthly solar generation
•  Annual solar generation
•  Estimated annual savings
•  Payment period
•  Simple Annual ROI
•  Electricity usage coverage
•  Long-term savings

You can then change one input at a time to see how installation cost, electricity rates or solar efficiency affect financial results.

How is solar ROI and payback calculated?

Financial accounting comes down to two important questions:

1. How much will a solar system cost?

2. How much money can this save each year?

The calculator estimates the initial investment using system size and installed cost per watt. Solar energy and electricity inputs are used to estimate savings.

Solar Payback Formula

Payback period = System cost ÷ Annual savings

Simple Solar ROI Formula

Simple Annual ROI (%) = Annual Savings ÷ System Cost × 100

These formulas are useful for comparing solar options, but they are simpler than a full investment analysis. A detailed financial assessment may also consider financing costs, maintenance, equipment replacement, inflation, discount rates, and other future cash flows.

Solar ROI vs. Payback Period

ROI and payback measure different aspects of a solar investment.

What does solar payback tell you?

Payment Answers:

How long can it take for accumulated savings to recover the original cost of a solar system?

A four-year simple return means that the estimated accumulated savings will equal the initial investment after approximately four years if the assumed savings are achieved.

What does solar ROI tell you?

Simple annual ROI answers:

How big is the estimated annual savings compared to the initial investment?

For example, a 25% simple annual ROI means the estimated annual savings are equal to 25% of the original system cost. No figure should be interpreted in isolation. Two solar systems with different installation costs, generation levels, and long-term performance may have similar payback periods.

What affects solar ROI in Pakistan?

Your solar return depends on more than just the size of the system.

Solar energy installation cost

The amount you pay upfront directly affects the payout. A more expensive system is a larger investment to recover, although the quality of the equipment, warranty, and scope of installation should also be considered when comparing prices. Compare complete quotations rather than selecting a system based solely on the lowest cost per watt.

Electricity tariff

Solar energy can be more financially valuable when it replaces electricity that would otherwise be purchased at a higher cost. Because tariffs can change, today’s electricity rate should not automatically be considered the rate you will pay over the life of the system.

Solar energy production

A system that produces more usable electricity could potentially replace more electricity purchased from the grid.

Depending on the breed:

•  System capacity
•  Available sunlight
•  Roof orientation
•  Panel tilt
•  Shading
•  Temperature
•  System performance
•  Condition of goods

Power consumption

Your property must be able to use or receive value from the electricity generated. Installing a large solar system does not automatically produce proportionately greater financial savings if the monetary value of the additional electricity is low.

System performance

The solar system is facing real-world losses. If the actual yield is lower than expected, the annual savings may also be lower, which can extend the payback period.

Maintenance and future costs

A simple ROI calculation cannot include every cost that occurs over the life of a solar system. Depending on the installation, future costs may include:

•  Care
•  Cleaning
•  Inverter replacement
•  Battery replacement
•  Repair
•  Financial expenses

Consider them separately when evaluating the long-term economics of a project.

Solar ROI Calculation Examples

Here are a few simple examples that show how the calculator’s financial formulas work.

Example 1: Calculating the cost of a solar system

Suppose you are considering:

Solar System Size: 10 kW
Installed Cost: PKR 135 per watt

The estimated cost of the system will be:

10 × 1,000 × 135 = PKR 1,350,000

This shows how the installed cost per watt directly affects the investment used in the ROI calculation.

Example 2: Calculating solar payback

Suppose your project has:

Initial system cost: PKR 1,200,000
Estimated annual savings: PKR 300,000

The easy payment would be:

1,200,000 ÷ 300,000 = 4 years

If annual savings remain at the same level, the accumulated savings will equal the original cost of the system after about four years.

Example 3: Calculating simple annual ROI

Using the same data:

System Cost: PKR 1,200,000
Annual Savings: PKR 300,000

The simple annual ROI would be:

300,000 ÷ 1,200,000 × 100 = 25%

This means that the estimated annual savings are equal to 25% of the original system cost. This does not mean that the investment is guaranteed to yield a 25% financial return every year.

How to get a better solar ROI estimate?

The quality of your results depends heavily on the information you enter.

For more useful calculations:

•  Use an existing solar installation quotation.
•  Enter your actual electricity consumption in kWh.
•  Review your electricity usage over several months.
•  Check that your electricity tariff is current.
•  Use realistic peak sun times for your location.
•  Use a reasonable system performance assumption.
•  Compare multiple solar quotes.
•  Test different hypotheses before making a decision.

Compare different scenarios.

Try changing one input at a time.

For example, compare:

•  Different prices for solar systems.
•  Different electricity rates
•  Different times of the sun
•  Different values of system performance

This helps you see which assumptions have the biggest impact on payout and ROI.

What is not included in the solar ROI calculator?

The calculator focuses on basic solar costs, production, savings, and payback.

This does not currently calculate:

•  Battery cost or battery ROI
•  Maintenance costs
•  Detailed roof shading
•  Structural adaptation
•  Electricity rates in the future with confidence
•  Net Present Value (NPV)
•  Internal Rate of Return (IRR)

It also does not provide a 25-year financial forecast guarantee. If your solar project involves financing, batteries, major equipment replacement or complex grid export arrangements, include these factors separately when evaluating the investment.

Who should use the solar ROI calculator?

The calculator may be useful for:

•  Homeowners are comparing solar prices.
•  Businesses Considering Rooftop Solar Power
•  Property owners comparing installation costs.
•  Buyers are estimating solar payments.
•  People are reviewing the installer’s ROI calculation.
•  Users comparing the sizes and costs of different systems

start with a solar size calculator before calculating ROI .