How Many Solar Panels Do I Need For 500 kWh Per Month? (Calculator + 2026 Numbers)
500 kWh/month = 6,000 kWh/year — about 57 % of U.S. average household use. At average sun, you need roughly 10 × 410 W panels (~4 kW DC). This is the right target for a small home, an apartment, or a house with gas heat where the electric bill is light. The system fits on ~210 sq ft of roof and costs about $12,400 installed in 2026 (no federal credit).
The Math
System kW = (500 × 12) / (PSH × 365 × 0.83) = 6,000 / (4.98 × 302.95) = 3.98 kW
Panels = 3,980 / 410 = 9.7 → 10 panels
State-By-State Panel Count
| Location | PSH | System kW | Panels (410 W) | Annual savings |
|---|---|---|---|---|
| Phoenix, AZ | 6.54 | 3.03 | 8 | $840 ($0.14/kWh) |
| Los Angeles, CA | 5.61 | 3.53 | 9 | $1,800 ($0.30/kWh) |
| Denver, CO | 5.66 | 3.50 | 9 | $840 ($0.14/kWh) |
| Austin, TX | 5.30 | 3.74 | 10 | $840 ($0.14/kWh) |
| Atlanta, GA | 5.04 | 3.93 | 10 | $780 ($0.13/kWh) |
| Boston, MA | 4.70 | 4.22 | 11 | $1,680 ($0.28/kWh) |
| New York, NY | 4.21 | 4.71 | 12 | $1,320 ($0.22/kWh) |
| Chicago, IL | 4.27 | 4.64 | 12 | $960 ($0.16/kWh) |
| Seattle, WA | 3.95 | 5.02 | 13 | $660 ($0.11/kWh) |
The range is 8 panels (Phoenix) to 13 panels (Seattle) — a manageable install in every case.
2026 Cost And Payback
| Location | Installed cost (4 kW) | Annual savings | Payback |
|---|---|---|---|
| Hawaii ($0.42/kWh) | $12,400 | $2,520 | 4.9 yr (with net metering) |
| California ($0.30/kWh) | $12,400 | $1,800 | 6.9 yr |
| Massachusetts ($0.28/kWh) | $12,400 | $1,680 | 7.4 yr |
| U.S. average ($0.165/kWh) | $12,400 | $990 | 12.5 yr |
| Washington ($0.11/kWh) | $12,400 | $660 | 18.8 yr |
Who Should Size For 500 kWh/Month?
- Small homes with gas heat and hot water (electric load is lighting, fridge, cooking, electronics)
- Apartments and condos with limited roof allocation
- Retirees or 1–2 person households with low consumption
- Budget-conscious buyers wanting partial offset (reduce the bill, not eliminate it) — see are solar panels worth it for the full financial analysis
If your goal is to fully offset a typical household, see how many solar panels to power a house. If you plan to add an EV or electrify heating, size for 1,000 kWh/month instead — the marginal cost of 10 extra panels is much less than a second installation visit later.
kWh
hrs
Required system size
0.00kW
To produce 1,000 kWh per month at 5.32 peak sun hours
If you use 100W panels
84
smaller, RV/cabin sized
If you use 300W panels
28
older residential standard
If you use 400W panels
21
current residential standard
1,000 kWh per month is roughly equivalent to an average US home (US average is ~899 kWh/month per EIA 2023).
4,452 kg
CO₂ avoided per year
1.1
equivalent US homes powered
205
trees planted equivalent
$1,920
estimated annual savings
Tap to see sensitivity analysisSensitivity analysis
| Scenario | Value |
|---|---|
| Low (-20%) | 6.7 kW |
| Expected | 8.4 kW |
| High (+20%) | 10.0 kW |
PSH varies seasonally \u2014 winter values can be 30% lower. To meet your target year-round, size for the worst month, not the average.
Keep Reading
- How Many Solar Panels For 1,000 kWh Per Month
- How Many Solar Panels For 2,000 kWh Per Month
- How Many Solar Panels For 2,500 kWh Per Month
- How Much Power A 5 kW Solar System Produces
- How Many Panels In A 1kW–20kW Solar System
- How To Calculate Solar Panel Output
- Average Peak Sun Hours By State
- Solar Panel Calculator — Full Energy Estimate
Frequently Asked Questions
How many solar panels do I need for 500 kWh per month?
At U.S. average sun (4.98 PSH) with PVWatts v8 derate 0.83: system kW = 6,000 / (4.98 × 365 × 0.83) = 3.98 kW. With 410 W panels: 10 panels. In sunny Phoenix: 8 panels. In cloudy Seattle: 13 panels.
Who uses 500 kWh per month?
About 57 % of U.S. average. Typical of: a 1-bedroom apartment, a small (1,000–1,500 sq ft) home with gas heat and gas water heater, a retired couple with modest usage, or a very energy-efficient home with LED lighting and efficient appliances.
How much does a 4 kW system cost in 2026?
About $12,400 installed at LBNL median $3.10/W DC. No federal tax credit in 2026 (Section 25D ended 2025-12-31).
What is the payback for 500 kWh/month of solar?
At U.S. average rates ($0.165/kWh): ~$12,400 / $990 per year = 12.5 years. In California ($0.30/kWh): 6.9 years. In Hawaii ($0.42/kWh): 4.8 years.
How much roof area for 500 kWh/month?
About 210 sq ft of panel area (10 × 21 sq ft each) plus ~30 % for setbacks = ~270 sq ft total. Fits easily on a single south-facing roof section.
Can a 500 kWh system also charge an EV?
A typical EV commute adds 250–350 kWh/month. If your base home usage is already 500 kWh, size for 750–850 kWh/month total — about 14–16 panels instead of 10. See [Solar Panels For 1,000 kWh/Month](/how-many-solar-panels-do-i-need-for-1000-kwh-per-month/).
Sources
Marko Visic
Physicist and solar energy enthusiast. After installing solar panels on my own house, I built TheGreenWatt to share what I learned. All calculators use NREL PVWatts v8 data and peer-reviewed formulas.