How many solar panels is a 5kW system?

A 5kW solar system typically requires between 15-25 solar panels. The exact number of panels needed depends on the wattage of the individual panels. Most home solar panels today range from 250-400 watts. Using 250W panels would require 20 panels for a 5kW system (5000W / 250W per panel = 20 panels). With 350W panels, you’d need around 14 panels (5000W / 350W per panel = 14.3 panels).

Typical Solar Panel Sizes for Residential Systems

For residential solar systems, solar panels typically range from 250W to 400W. Here are some of the most common panel sizes:

  • 250W
  • 300W
  • 325W
  • 350W
  • 390W

High efficiency panels may go up to 400W or above, but those are less common for homes. The wattage indicates the amount of power each panel can produce under ideal conditions.

How Many 250W Solar Panels Are Needed for 5kW?

If using 250W solar panels, you would need 20 panels to achieve 5kW of solar capacity:

  • Each 250W panel produces 250 watts
  • 5,000W system / 250W per panel = 20 panels

So with twenty 250 watt solar panels, you can get a system size of 5,000 watts or 5kW.


The formula to determine how many 250W panels you need for a 5kW system is:

System watts / Panel watts = Number of panels

So for a 5kW system with 250W panels:

5,000W / 250W = 20 panels

How Many 300W Solar Panels for 5kW?

With 300W solar panels, you would need around 17 panels to achieve 5kW:

  • 300W panel x 17 panels = 5,100W

17 x 300W panels produces 5,100 watts, just slightly over the 5kW target system size. Rounding down, 17 panels is the ideal number to buy.


The formula for a 5kW system using 300W panels is:

5,000W / 300W per panel = 16.67 panels

Rounding up to the nearest whole number gives you 17 panels.

How Many 325W Solar Panels for 5kW?

With higher efficiency 325W panels, you would need around 15 panels for a 5kW system:

  • 325W panel x 15 panels = 4,875W

15 solar panels at 325W each produces a system size of 4,875 watts, which is just under the 5kW total. This allows some room for production variance while still meeting the 5kW nominal size.


The calculation to determine the number of 325W panels needed is:

5,000W / 325W per panel = 15.38 panels

Rounding down gives you 15 panels for your 5kW solar array.

How Many 350W Solar Panels for 5kW?

For 350W solar panels, you would need around 14 panels for a 5kW residential system:

  • 350W panel x 14 panels = 4,900W

14 x 350W panels produces 4,900 watts. This is just under the full 5kW capacity, allowing for real world efficiency and performance variance.


To calculate the number of 350W panels needed:

5,000W system / 350W per panel = 14.29 panels

Rounded down to the nearest whole number gives you 14 panels for a 5kW system size.

How Many 400W Solar Panels for 5kW?

For a solar panel wattage of 400W, you would need around 12-13 panels for a 5kW system. Let’s calculate both options:

  • 12 x 400W panels = 4,800W
  • 13 x 400W panels = 5,200W

With 12 panels you get 4.8kW capacity, which is a little low for the 5kW target. 13 panels gets you 5.2kW, slightly above the target.

To stay closest to the 5kW system size, 13 x 400W panels is ideal.


The calculations are:

5,000W / 400W per panel = 12.5 panels

Rounding up gives 13 panels for a 5kW solar system using 400W panels.

Solar Panel Wattage Comparison Table

Here is a table summarizing the number of solar panels needed for a 5kW residential solar system at different wattages:

Solar Panel Wattage Number of Panels for 5kW
250W 20
300W 17
325W 15
350W 14
400W 13

As you can see, higher wattage solar panels require fewer total panels to meet the 5kW system size. However, higher wattage panels are typically more expensive on a per-watt basis.

To optimize value, you generally want to choose panels with higher wattages than 250W. Many homeowners opt for 300-350W panels to get an efficient system at a reasonable cost.

Other Factors That Affect Number of Solar Panels

While the solar panel wattage dictates the number of panels needed, there are a few other factors that can impact the total panel count:

  • Roof Space – Your roof size and layout will ultimately limit the number of panels that can fit.
  • Shading – Any shading on your roof from trees or other obstacles will reduce production of affected panels.
  • Orientation – Optimal panel orientation facing south provides highest production. Other orientations produce less.
  • Local Electricity Cost – If electricity is very expensive where you live, you may want to oversize your system to produce more power and maximize savings.

Your solar installer will take all these factors into account when designing your system to maximize production and savings while staying close to your 5kW size target.

Expanding Your Solar System Later

One advantage of solar is that it’s modular and expandable over time. Once your initial system is installed, you can always add more panels later to increase the kW capacity if needed.

Starting with a smaller 3-5kW system is often most affordable for homeowners. But solar systems are designed for easy expansion when you’re ready for more production.

Getting Multiple Quotes

The best way to determine the optimal number of solar panels and choose the right installer is to get quotes from multiple local installers. Be sure to get:

  • Detailed project plan and panel layout
  • Production estimates
  • Full cost breakdown
  • Information about financing options

Comparing multiple quotes will help you find the installer and panel configuration that best fits your roof space, production goals, and budget.

Key Takeaways

To summarize the key points:

  • A 5kW solar system typically needs between 15-25 solar panels depending on the wattage (250W to 400W) of the panels used.
  • Higher wattage panels require fewer total panels, but tend to cost more per watt.
  • 300-350W panels are a good option for an efficient 5kW residential system.
  • Your specific home setup and roof space will impact the ideal number of panels.
  • Get quotes from multiple local installers to determine the best system design and value. Most provide free quotes.

With the right number and placement of solar panels, you can maximize production from your 5kW solar array while minimizing cost. And you’ll be generating clean, renewable power from the sun for decades to come!

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