Solar Savings Calculator

Enter your average electricity bill, electricity rate, city, usable roof area and roof conditions to estimate your solar system size, annual power production, installation cost, potential bill reduction and long-term savings.

The calculator is designed to help you compare different solar options before requesting a detailed quotation.

Important: The calculator does not separately value solar power used directly on your property and power exported to the grid. If you expect to export a significant portion of your solar production, review the net billing information below when estimating your savings.

What is the solar savings calculator estimate?

The calculator combines your electricity costs, available roof space, and local solar conditions to estimate how a rooftop solar system might work out financially.

It can calculate:

•  Recommended solar system size in kilowatts
•  Approximate installation cost
•  Estimated annual solar production in kWh
•  Possible electricity bill offset
•  Estimated monthly bill before and after solar energy
•  Estimated CO₂ reduction
•  Effect of shading on solar generation
•  Long-term savings based on your chosen electricity rate increases

The available roof space is also taken into account. If your electrical usage indicates that you need a system larger than your roof, the recommended capacity is limited by the usable roof area you have available.

How to use the solar savings calculator?

1. Enter your average monthly electricity bill.

Enter a monthly bill that reasonably represents your typical electricity usage. If your electricity consumption changes significantly throughout the year, avoid using only the highest summer bill. For a better estimate, look at a few recent bills. If available, reviewing 12 months of electricity consumption in kWh gives you a clearer picture of your actual energy needs.

2. Enter your electricity rate.

Enter the electricity rate you want the calculator to use. Where possible, use a realistic rate based on your current electricity bill rather than a general nationwide figure. Your actual electricity price may vary depending on your customer category, consumption, and other billing components.

3. Enter the installed cost per kWh.

If you already have a quote from a solar installer, determine the full install cost per kilowatt and enter that figure. Check what is included in the price before using the quotation.

Your installation cost may be included.

•  Solar panels
•  Inverter
•  Mounting structure
•  Electrical protection equipment
•  Wiring
•  Installation labor
•  Approval or request work
•  Battery storage, where applicable.

The calculator does not calculate battery costs separately. If batteries are included in your planned system, make sure their cost is included in the figures you enter.

4. Select your city.

Choose the city or closest available location that best represents your property. Location matters because the amount of solar energy available varies across Pakistan. The calculator uses your selected location when estimating solar energy.

5. Enter your usable roof area.

List only the portion of your roof that can actually be used for solar panels.

Do not include the space occupied by:

•  Water tanks
•  Staircase rooms
•  Skylights
•  Permanent structures
•  Other important obstacles

When determining the extent of a rooftop-based system, the calculator uses approximately 100 square feet of roof space per 1 kW of solar capacity. Actual space requirements may vary depending on panel dimensions, panel wattage, mounting arrangements, row spacing and roof layout.

6. Enter the roof slope and orientation.

Select the tilt and orientation that most closely matches the area where the solar panels will be installed. Both factors can affect how much sunlight reaches the panels and when that sunlight is available during the day. The final mounting location should be confirmed during a professional site survey.

7. Estimate regular shading.

Enter the estimated percentage for regular shade affecting the proposed panel area.

Common sources of shade include:

•  Nearby buildings.
•  Tree
•  Water tanks
•  Parapet or boundary walls
•  Other roof structures

Estimate the shade in the area where the panels will actually be installed, rather than your entire property.

8. Choose the rate of tariff increase.

This setting lets you see how future increases in electricity prices could affect expected long-term savings. Since, future electricity rates cannot be known in advance, try several values instead of relying on a single assumption.

How does the solar savings calculator work?

The calculator first estimates your monthly electricity consumption using the electricity bill and rate you entered. It then calculates the solar capacity needed to meet that level of electricity demand and checks whether the system can fit into your available roof space.

Demand-based solar system sizing

The size calculation uses:

Monthly electricity consumption ÷ (30 × daily solar hours × efficiency ratio)

Maximum capacity based on roof area

The available roof space is estimated as follows:

Usable roof area ÷ 100 square feet per kW

The calculator compares demand-based system size with rooftop-based capacity and uses the lower figure as the recommended solar system size.

Estimated Annual Solar Generation

The annual generation is estimated using:

System capacity × solar hours × 365 × performance assumptions × orientation adjustment × shading adjustment

The efficiency and derating values used in this calculation account for expected system losses. They should not be read as a guarantee of actual system performance.

Understanding your solar savings results

Recommended size of solar system

This is an estimate of solar potential based on two main factors:

•  Your calculated electricity requirement
•  Usable roof space is available.

Think of this as a starting point for system selection. The solar installer can recommend a different capacity after checking your monthly electricity consumption, approved load, inverter requirements, panel wattage, roof dimensions, and expected future electricity usage.

Estimated cost of solar system

The estimated system cost is calculated as follows:

Recommended system size × installed cost per kW

Using a recent, complete installer quotation will give you a more relevant estimate than relying on an old or general market price. The calculated amount is an estimate and not an installation quotation.

Annual solar generation

It shows how much electricity the selected solar system can generate in a typical year, based on the calculator’s solar and system performance assumptions.

The actual breed may vary due to:

•  Weather
•  Temperature
•  Dust
•  Shading
•  Equipment performance
•  Installation quality
•  System downtime

Electricity bill offset

Bill offset shows how much of your expected electricity needs can be generated by solar energy. For example, a 70% bill offset does not mean that your final electricity bill will be exactly 70% lower. Your final bill can also be affected by grid electricity imports, fixed charges, taxes, exported electricity, and when you use electricity during the day.

Electricity bill before and after solar energy

This comparison gives you a simple idea of how your monthly electricity costs could change after installing solar energy. The figure is useful for comparing different solar setups, but your actual bill will depend on your electricity usage and applicable billing arrangements.

Estimated 25-year solar savings

25 years of data estimate how your savings could accumulate over time based on your chosen electricity price increases. It is best viewed as an estimate of potential overall savings. Long-term costs such as maintenance, equipment replacement, financing, system degradation and future regulatory changes can also affect overall financial results.

How Pakistan’s 2026 net billing could affect your savings.

Solar energy can generally be used in two ways:

1. Used directly on your property.

2. The power grid was exported.

The financial value of these two types of solar electricity may not be the same.

Under NEPRA’s Prosumer Regulations as described in the source material, electricity purchased from a distribution licensee is charged at the applicable tariff, while electricity exported by a professional is credited as per the applicable National Average Energy Purchase Price Mechanism.

The NAEPP estimates Rs 8.13 per kilowatt hour for 2026 .

This means that the financial value of using your solar electricity directly on your property may be different than the price you receive for electricity exported to the grid.

Why does daytime electricity consumption matter?

How much electricity you use during solar production hours can have a significant impact on your savings.

Consider two properties that use the same amount of electricity each month. During daylight hours, businesses can directly use a large portion of their solar output by operating machinery, air conditioning, and office equipment.

A household that is mostly empty during the day but uses more electricity at night can export a large portion of its solar energy production during the day. Both systems can produce the same amount of electricity while producing different financial results.

What about current Prosumer contracts?

The source material notes that regulatory treatment may be different for contracts established under earlier rules.

It said that the April 2, 2026 amendment to NEPRA allows valid contracts entered into under the previous regulations to continue under their previous rates and billing mechanisms until the end of the contract period, with conditions relating to material changes to the generation facility.

Check the latest laws applicable to your connection and contract as regulations and rates may change.

What is the biggest impact on solar energy savings?

Several factors determine how much money a solar power installation can save.

Power consumption

Properties that use more electricity may require larger solar systems. Where possible, use actual kWh instead of relying solely on the rupee value of your electricity bill.

Daytime electricity usage

Electricity generated and used immediately on the property may have a different monetary value than electricity exported to the grid. For this reason, when you use electricity makes almost as much difference as how much electricity you use.

Available roof space

A high electricity bill does not automatically mean that a large solar system can be installed. Your roof must have enough usable space for the desired number of panels. The calculator calculates this by limiting the recommended capacity according to the entered roof area.

Shading

Regular shading reduces the amount of sunlight reaching your solar panels. If you have more than one potential installation area, try different shading values to compare.

Roof orientation and tilt

The orientation and angle of your solar panels affect their sunlight exposure. The final layout must balance solar exposure with the practical requirements of roof structure, safety, accessibility, and installation.

Installation cost

The amount you pay for the system directly affects its financial performance. Use a recent, itemized quotation whenever possible so you know what is included.

Electricity rates

Higher electricity costs can directly increase the value of solar power used on your property. Future tariffs are uncertain, so long-term calculations using several tariff scenarios are better.

Export compensation

If your system is likely to export a large amount of electricity, the applicable export rate can have a significant impact on your total savings.

Examples of solar savings:

Example 1: When roof space limits your solar system.

Suppose your usable roof area is:

600 square feet

The calculator currently allows approximately:

100 square feet = 1 kilowatt

So your estimated maximum roof space will be:

600 ÷ 100 = 6 kW

If your electricity usage suggests you need an 8 kW system, the calculator will limit its recommendation to around 6 kW due to available roof space. This helps prevent the calculator from recommending a system that exceeds the listed roof area limit.

Example 2: How shading changes solar energy?

Solar system is estimated to produce 8,000 kWh per year before considering shading .

Compare:

Scenario A: 0% shade
Scenario B: 15% shade

The shading adjustment used by the calculator is:

1 – Percentage of shedding

With 15% shading:

8,000 × 0.85 = 6,800 kWh

In this example, the estimated annual production drops from 8,000 kWh to 6,800 kWh.

This is an example of how the calculation works, not an estimate of live production for a particular city.

Example 3: Converting your electricity bill to estimated usage

Suppose your monthly electricity bill is:

Rs. 24,000

And the listed electricity rate is:

Rs. 48 per kilowatt

The calculator will estimate monthly electricity consumption as follows:

24,000 ÷ 48 = 500 kWh per month

The system size calculation will then use the solar hour value for your selected location along with the calculator’s performance assumptions.

This is why it is important to use a realistic electricity rate when estimating consumption from the price of your bill.

Example 4: Comparing future electricity price scenarios

You can also use the calculator to compare different assumptions about future electricity prices.

For example:

Scenario A: 0% annual tariff increase
Scenario B: 5% annual tariff increase

Do not make any changes to the property, roof, and solar system inputs. The physical solar system and its initial estimated generation remain based on the same inputs, while the long-term savings estimate changes according to the chosen electricity price scenario.

How to get a more realistic solar savings estimate?

For more useful calculations:

•  Review recent electricity bills.
•  Use actual kWh consumption when available.
•  Enter the usable roof area instead of the total roof area.
•  Estimate the shade in the proposed panel area.
•  Use a recent, all-inclusive solar installation quotation.
•  Check if batteries are included in the quoted price.
•  Compare several electricity tariff scenarios.
•  Consider how much electricity you use during daylight hours.
•  Check the export credit rules that apply to your connection.
•  Compare your results with detailed system size, yield, ceiling, and ROI before purchasing equipment.

Important factors that the calculator cannot fully predict

The calculator provides an estimate based on the information entered. Actual solar production and financial savings may vary due to:

•  Weather and temperature
•  Dust and panel cleaning
•  Physical shedding
•  Panel specifications
•  Inverter performance
•  Wiring Disadvantages
•  Installation quality
•  Time to shut down equipment
•  Roof geometry
•  Power consumption patterns
•  Fixed electricity charges and taxes
•  Future electricity rates
•  Export compensation
•  Solar panel degradation
•  Maintenance costs
•  Inverter or battery replacement
•  Financial expenses
•  Changes to regulations

For this reason, the 25-year savings estimate should not be considered a guaranteed return. A professional structural and electrical assessment is recommended before purchasing or installing a solar system.

Who should use this solar savings calculator?

This calculator is designed for people in Pakistan who want to understand the potential cost, system size, and savings of rooftop solar before requesting or comparing installer quotations.

This may be useful for:

•  Homeowners are considering rooftop solar power.
•  Businesses with significant electricity consumption during the day
•  Property owners are comparing solar quotations.
•  People are checking if their roof can accommodate the required system.
•  Comparing shaded and unshaded roof areas
•  Buyers comparing different installation costs
•  Anyone who is estimating potential long-term solar savings.