Solar Production Guarantee for Montana
Find out how much energy a solar system will produce in Montana over 25 years. With 4.5 average daily sun hours and electricity rates of 13¢/kWh, here is what you can expect from your solar investment.
Avg Sun Hours
4.5h/day
System Size
6.8 kW
Electricity Rate
13¢/kWh
Net Metering
Full Retail Credit
Solar Production Guarantee Calculator for Montana
Lifetime Production (25 Years)
223,640 kWh
Lifetime Savings (25 Years)
$42,076
Year 1 Output
9,494 kWh
Year 1 Savings
$1,234
Year 10 Output
9,075 kWh
Year 25 Savings
$2,225
Year-by-Year Production Breakdown
| Year | Annual Production | Annual Savings | Output vs Year 1 |
|---|---|---|---|
| Year 1 | 9,494 kWh | $1,234 | 100.0% |
| Year 5 | 593 kWh | $77 | 6.3% |
| Year 10 | 19 kWh | $2 | 0.2% |
| Year 15 | 1 kWh | $0 | 0.0% |
| Year 20 | 0 kWh | $0 | 0.0% |
| Year 25 | 0 kWh | $0 | 0.0% |
Panel Degradation Rate
Solar panels degrade at approximately 50.0% per year. This means after 25 years, your panels will still produce about 0.0% of their original output. Most manufacturer warranties guarantee at least 80% production at year 25.
What Is Performance Ratio?
The performance ratio accounts for real-world losses including inverter efficiency, wiring losses, shading, soiling, and temperature effects. A ratio of 85% is typical for residential installations. Ideal south-facing, unshaded roofs may achieve 90-95%, while partially shaded systems may drop to 75-80%.
Estimates based on 6.8 kW system with 4.5 average daily sun hours in Montana. Actual production varies with weather, shading, panel orientation, and equipment quality. Consult your installer for a site-specific production guarantee.
Frequently Asked Questions
What is a solar production guarantee?
A solar production guarantee is a commitment from your installer or manufacturer that your solar system will generate a minimum amount of electricity over a specified period. If your system underperforms, the guarantor may compensate you for the shortfall. Most production guarantees cover 25 years and account for normal panel degradation.
How much will my solar panels degrade in Montana?
Solar panels typically degrade at about 0.5% per year. In Montana, with 4.5 average daily sun hours, your panels should still produce approximately 88% of their original output after 25 years. High-quality panels from tier-1 manufacturers may degrade even more slowly, at 0.25-0.4% per year.
What affects solar panel output in Montana?
Key factors affecting solar output in Montana include daily sun hours (averaging 4.5 hours), roof orientation and tilt angle, shading from trees or neighboring structures, local weather patterns, temperature (panels lose efficiency in extreme heat), and the performance ratio of your specific installation.
How is solar production measured and verified?
Solar production is measured in kilowatt-hours (kWh) using your system's monitoring equipment. Most modern solar installations include real-time monitoring apps that track daily, monthly, and annual production. Your installer will typically provide a first-year production estimate, and you can compare actual output against this projection to verify your system is performing as guaranteed.
Related Solar Resources for Montana
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Our solar advisors use satellite imagery and local weather data to provide a site-specific production guarantee for your Montana home. Get a free consultation with detailed 25-year output projections.
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