Solar panels can significantly reduce your electricity bills, but the actual savings depend on several factors. Here's how to calculate your potential savings.
The Basic Formula
**Annual Savings = System Size (kW) × Peak Sun Hours × 365 × Electricity Rate**
Understanding Each Factor
### System Size Residential solar systems typically range from 3 kW to 10 kW. A 6 kW system is common for average homes.
### Peak Sun Hours This isn't the number of daylight hours — it's the equivalent hours of full sunlight. Most locations get 3-6 peak sun hours per day.
- Southwest US: 5-6 hours
- Southeast US: 4-5 hours
- Northeast US: 3-4 hours
- Northern Europe: 2.5-3.5 hours
### Electricity Rate Higher electricity rates mean greater savings. Rates range from $0.10/kWh to $0.30+/kWh depending on location.
Example Calculation
A 6 kW system in a location with 5 peak sun hours and $0.15/kWh electricity:
- Daily production: 6 kW × 5 hours = 30 kWh
- Annual production: 30 × 365 = 10,950 kWh
- Annual savings: 10,950 × $0.15 = $1,642.50
10-Year and 20-Year Savings
Solar panels typically last 25+ years. Over 20 years (accounting for 0.5% annual degradation):
- Year 1: $1,642
- Year 10: $15,836 (cumulative)
- Year 20: $30,834 (cumulative)
Factors That Affect Savings
1. **System efficiency**: Higher quality panels produce more electricity 2. **Roof orientation**: South-facing roofs produce the most energy 3. **Shading**: Trees and buildings reduce production 4. **Electricity rate changes**: If rates rise, savings increase 5. **Net metering**: Selling excess energy back to the grid adds savings 6. **Incentives**: Tax credits and rebates reduce payback time
The Federal Tax Credit
The US federal solar tax credit (ITC) covers 30% of installation costs. On a $18,000 system, that's $5,400 in tax savings, bringing the net cost to $12,600.
Payback Period
Most residential solar systems pay for themselves in 7-12 years. After that, the electricity they produce is essentially free for the remaining 15+ years of their life.
Calculate your solar savings with our Solar Savings Calculator, then estimate your current electricity costs with our Electricity Cost Calculator.