Convert Between Panel Count and System Size
Enter either value and see the automatic conversion
Typical: 15-25 panels
Typical: 5-10 kW
Modern panels: 300-400W typical, 350W is average. Older panels may be 250-300W.
Your System Summary
20 solar panels
at 350W each
7 kW system
Phoenix Production Estimate:
Annual Production
12,264 kWh
Annual Value (@ 15¢/kWh)
$1,839.60
Quick Reference Guide
Common Residential Systems:
- • 5 kW = 14-17 panels
- • 6 kW = 17-20 panels
- • 7 kW = 20-23 panels
- • 8 kW = 23-27 panels
- • 10 kW = 29-33 panels
Panel Wattage by Era:
- • 2024-2025: 350-450W (high efficiency)
- • 2020-2023: 320-400W (modern)
- • 2015-2019: 280-340W (standard)
- • 2010-2014: 250-300W (older)
Where to find your system info: Check your solar installation paperwork, inverter display, monitoring app, or count panels on your roof. Most modern residential systems in Phoenix are 5-10 kW (18-28 panels).
Understanding Solar System Sizing
Many Phoenix homeowners know how many solar panels they have but aren't sure about their system's kilowatt (kW) rating—or vice versa. This simple conversion tool helps you understand your solar system's specifications, which is essential for calculating cleaning costs, estimating production, and planning maintenance.
How the Conversion Works
Solar panels are rated by their power output in watts (W). Modern residential solar panels typically produce between 300-400 watts each, with 350W being a common current standard. Your system's total kilowatt (kW) rating is calculated by multiplying the number of panels by each panel's wattage, then dividing by 1,000.
Formula: System Size (kW) = (Number of Panels × Panel Wattage) ÷ 1,000
Example: 20 panels × 350W = 7,000W = 7 kW system
Why System Size Matters
Knowing your system size in kilowatts is important for several reasons:
- Cleaning Quotes: Professional cleaners often price by panel count or system size
- Production Estimates: Annual energy production is typically calculated per kW installed
- Maintenance Planning: Larger systems may require more frequent cleaning
- Insurance & Warranties: Documentation often references kW rating
- System Monitoring: Performance metrics are usually shown per kW
Common Residential System Sizes in Phoenix
Most residential solar installations in Phoenix fall within the 5-10 kW range, though system size depends on several factors including home size, energy usage, available roof space, and budget. Here's what different system sizes typically look like:
Typical System Configurations:
- Small System (4-5 kW): 12-15 panels, suitable for smaller homes or partial offset
- Medium System (6-7 kW): 17-20 panels, ideal for average-sized homes
- Large System (8-10 kW): 23-28 panels, great for large homes or full offset
- Extra Large (11-15 kW): 31-43 panels, for very large homes or electric vehicle charging
Panel Wattage Over Time
Solar panel technology has improved significantly over the years, with newer panels producing more power in the same physical size. If your system was installed several years ago, your panels likely have a lower wattage rating than current models:
- 2024-2025 Installations: 350-450W panels (high-efficiency models)
- 2020-2023 Installations: 320-400W panels (modern standard)
- 2015-2019 Installations: 280-340W panels (standard efficiency)
- 2010-2014 Installations: 250-300W panels (older technology)
- Pre-2010 Installations: 200-280W panels (early residential solar)
This is why it's helpful to know when your system was installed or to check your installation documentation for the exact panel specifications. If you're unsure, using 350W as an average provides a reasonable estimate for most modern systems.
Finding Your System Information
If you need to find your exact system specifications, here are the best places to look:
- Installation Paperwork: Your solar installation contract or completion documents
- Inverter Display: Many inverters show system size and panel count
- Monitoring App: Solar monitoring systems usually display full system specs
- Utility Interconnection: Your utility company's solar agreement documents
- Physical Count: Count panels on your roof (be safe, use binoculars!)
- Panel Labels: Individual panels have wattage labels, though these may be hard to read
Phoenix Solar Production by System Size
Once you know your system size, you can estimate annual energy production using Phoenix's excellent solar resource. Phoenix systems produce approximately 1,752 kWh per installed kW annually. Here's what that means for different system sizes:
| System Size | Panel Count (350W) | Annual Production | Annual Value (@15¢/kWh) |
|---|---|---|---|
| 5 kW | 14-15 panels | 8,760 kWh | $1,314 |
| 6 kW | 17-18 panels | 10,512 kWh | $1,577 |
| 7 kW | 20 panels | 12,264 kWh | $1,840 |
| 8 kW | 23 panels | 14,016 kWh | $2,102 |
| 10 kW | 28-29 panels | 17,520 kWh | $2,628 |
These production values assume clean, well-maintained panels operating at peak efficiency. Dirty panels can reduce production by 15-30%, which is why regular professional cleaning is so important in Phoenix's dusty desert environment.