How to use the solar panel placement calculator?

You can plan your roof in two ways.

Option 1: Use a satellite roof map:

1. Find your property.

Search for your address or use the location option to move the map to your property.

2. Trace the usable roof area.

Mark out the area of the roof where solar panels could potentially be installed. Leave out areas that you already know cannot be used.

3. Enter your panel details.

Include panel wattage and physical dimensions. If you are comparing a specific panel model, use the measurements provided on the manufacturer's specification sheet.

4. Choose the direction of the panel.

Select the available orientation setting that best matches your planned layout.

5. Add an edge setback.

Enter the clearance you want to leave around the perimeter of the roof. Required clearances may vary depending on the property, mounting system, and local installation requirements. Consider this value as a planning input rather than a substitute for professional design.

6. Review the estimate.

Satellite Planner can show:

•  Estimated number of panels
•  Estimated system capacity in kWp
•  Selected roof area
•  Estimated annual energy production

Option 2: Enter the roof dimensions manually:

Use the manual planner if you have already measured the roof section or want to compare layouts using specific dimensions.

1. Enter the width and height of the roof.

Measure a usable rectangular roof area. You can enter the measurement in meters or feet.

2. Select or enter your panel size.

Select a panel model where available or manually enter the panel width, length, and wattage. Physical dimensions are important because two panels with the same wattage rating can take up different amounts of roof space.

3. Test Portrait, Landscape or Auto Best

Portrait and landscape layouts use the same panel but rotate its position. Changing the orientation can affect how many full panels fit in the available ceiling space. If you want the planner to compare the available arrangements and find the option that best fits the most panels.

4. Insert the panel into place.

Add the gaps you plan to leave between adjacent panels. This gives you a more realistic layout than assuming the modules will be installed directly against each other.

5. Add an edge setback.

Secure the space between the solar array and the exterior roof edge. Do not assume that a typical setback is a legal requirement for your property. Final clearance requirements should be verified for actual installation.

6. Add ceiling barriers.

Add a chimney or skylight where needed and place it on the layout. This gives you a clear picture of how unavailable roof space can affect both the number and arrangement of panels.

7. Review the results.

The planner estimates:

•  Number of panels installed
•  Total system size
•  Roof coverage
•  Estimated array weight

What does the solar panel placement calculator tell you?

Panel Count

Panel count is the estimated number of complete modules that can fit within the planned roof area after taking into account panel dimensions, orientation, spacing, and setbacks. A large roof does not necessarily mean that every part of it can or should be covered with panels. Obstacles and usable installation space also affect the final layout.

System size

The capacity of the system is calculated by the number of panels and their selected wattage. Using more panels or higher wattage modules can increase the potential capacity of the system, provided the panels physically fit on the roof.

Physical fit and the size of the solar system required are separate considerations. Your roof may have more than enough space for more capacity than your property requires, or the system you need may exceed the usable roof space.

Roof coverage

Roof coverage shows how much of the planned roof area is occupied by solar panels. This is especially useful when comparing different panel sizes or orientations.

Estimated annual production

Satellite Planner can provide an annual energy estimate based on the selected system capacity and production input. Consider this as a planning estimate rather than a guarantee of production data. Actual solar production may vary due to:

•  Solar radiation
•  Roof direction
•  Roof slope
•  Shading
•  Temperature
•  Dust
•  Equipment Disadvantages
•  Other site-specific terms

Estimated array weight

The manual planner provides an estimated total array weight. This figure does not confirm that your roof can structurally support the installation. Roof condition and structural capacity should be assessed separately where necessary.

What affects solar panel placement?

Available roof space

Start with the area that can actually be used for solar panels, rather than the usable installation area of the property. Some areas may not be available for this reason:

•  Chimneys
•  Skylights
•  Water tanks
•  Roof access
•  Equipment
•  Parapets
•  Objects that create shadows
•  Other installation restrictions

The calculator can calculate selected constraints, but a professional roof survey can identify additional limitations.

Solar panel dimensions

Panel wattage alone does not determine how many modules will fit on a roof. The physical width and length of each panel are equally important. A higher wattage panel may provide more rated power per module, but it may also be physically larger. When roof space is limited, compare both panel wattage and dimensions.

Portrait vs. Landscape Placement

Portrait and landscape layouts use the same panels in different orientations. Portrait can allow more modules to fit on a given roof shape, while landscape can make better use of a narrow or oddly shaped area. Testing both layouts is more reliable than assuming that one orientation will always provide the most number of panels.

The difference between the panels

Solar panels typically require some separation to allow for hardware and practical installation. The manual planner lets you add spacing between panels so that the layout doesn't assume each module will sit directly against the next. Where possible, use spacing that matches the proposed mounting system.

Edge setbacks

An edge setback leaves a clearance between the solar array and the roof edge. Requirements may vary depending on the roof design, access requirements, mounting system, and local regulations. The calculator lets you test how different setback values affect usable roof space, but it does not determine the legally required clearance for your property.

Chimneys and skylights

Roof obstructions reduce usable installation space and can change the most practical panel layout. Including chimneys or skylights in the manual layout provides a more realistic panel count estimate than calculating from the total roof area alone. The calculator does not perform detailed shade modeling for these items.

Roof direction

Pakistan is in the northern hemisphere, so a solar array facing the equator usually faces south. However, orientation is only one part of the solar system design. Roof pitch, shading, available space, and power usage patterns can also affect the final layout.

East and west facing roof sections may still be suitable, depending on the property and project requirements.

Solar panel placement in Pakistan

The available roof space is often one of the first things to consider before deciding on the size of a solar system. A practical planning process is:

• 1. Estimate your electrical needs.
• 2. Determine the size of the solar system according to your needs.
• 3. Check whether the required number of panels will physically fit on your roof.
• 4. Evaluate the overall suitability of the shading and roof.
• 5. Estimate the expected energy production.
• 6. Confirm the final configuration and system design with your installer.

For example, deciding that you need a specific kilowatt system does not automatically mean that the required panels will fit. Panel wattage, physical dimensions, roof shape, spacing, obstructions, and obstacles affect the final configuration.

Example of solar panel layout

Example 1: Comparing portrait and landscape:

Input

•  A rectangular roof section
•  Known roof width and height
•  Selected panel dimensions
•  Selected panel wattage
•  Same panel gap and edge back

Run the layout once in portrait and then again in landscape.

Expected result

The number of panels can change because rotating the modules changes how their width and length fit into the available roof dimensions.

Why is this example useful?

This shows why the roof area in square meters alone does not determine how many panels can fit.

Example 2: Roof with skylight:

Input

•  Roof dimensions
•  Selected solar panel model
•  General spacing and setbacks
•  A skylight obstruction

Calculate the layout before and after adding a skylight.

Expected result

The available panel configuration may change as some part of the roof is no longer available for installation.

Why is this example useful?

This shows why a simple calculation of roof area can increase the amount of usable space available for solar panels.

Example 3: Comparing two panel models:

Input

Run the same roof layout using two panel models with different dimensions and wattage ratings. Keep roof dimensions, gaps, and setbacks consistent.

Expected result

One model may allow for more individual panels to fit, while another may provide a higher rated system capacity. The result depends on the dimensions and wattage of the panels being compared.

Why is this example useful?

This helps you compare how efficiently different panel models use available roof space, rather than choosing panels based on wattage alone.

Tips for a more accurate roof layout estimate

•  Use the manufacturer's actual panel dimensions.
•  Measure the usable roof space rather than the total dimensions of the property.
•  Add realistic edge clearance.
•  Add known ceiling obstacles.
•  Compare portrait and landscape settings.
•  Don't assume that every visible part of the roof can be used.
•  Check the shading separately.
•  Compare the available roof space with the size of solar system you need.
•  Confirm final measurements and installation requirements before purchasing equipment.

Important limitations

This calculator is designed for initial solar planning. It should not be considered as a construction drawing, structural evaluation or final engineering design. Depending on the planner and the information entered, the estimate may not be:

•  Detailed roof pitch and tilt
•  Precise shading all year round
•  Irregular or complex roof geometry
•  Multiple roof planes within a manual layout
•  Structural roof capacity
•  Mounting System Engineering
•  Electrical string design
•  Inverter compatibility
•  Local installation requirements
•  Precise on-site measurement
•  Rooftop areas that are not marked as unavailable.

Satellite imagery can also vary in age, clarity, and measurement accuracy. Use the results to explore possible configurations and compare different scenarios, then have the final design verified by a qualified solar professional.

Who should use this calculator?

This tool can help:

•  The homeowners are planning solar power on the roof.
•  Property owners are comparing solar panel options.
•  Solar energy buyers are checking to see if the proposed system will fit.
•  Installers are developing initial layout ideas.
•  Commercial property owners are estimating the roof capacity.
•  Anyone comparing solar panel sizes before installation