Solar Performance, Reliability & Warranties

A solar system is a 25+ year investment. Understanding how your system performs over time, what can affect its output, and what warranty protections you have ensures you can plan confidently. Here is what Alberta homeowners should know about long-term solar performance.

Seasonal Performance in Alberta

Solar production in Alberta follows a predictable seasonal pattern. The longest days and highest production occur from May through August, with June and July typically being peak months. Production drops during shorter winter days but does not stop entirely.

A typical 10 kW system in Calgary produces roughly:

Summer months (May-Aug): 1,200 to 1,500 kWh per month
Shoulder months (Mar-Apr, Sep-Oct): 700 to 1,000 kWh per month
Winter months (Nov-Feb): 300 to 600 kWh per month
Annual total: 12,000 to 14,000 kWh per year

These numbers can vary based on panel orientation, tilt angle, and shading. South-facing panels at a 30 to 45 degree tilt angle optimize annual production in Alberta's latitude.

Monitoring Your System

Modern solar systems come with monitoring platforms that let you track production in real time through a phone app or web portal. Monitoring serves several purposes:

Verify your system is performing as expected
Identify production drops that might indicate an issue
Track energy production and savings over time
With microinverters, monitor each individual panel's performance

Common monitoring platforms include Enphase Enlighten (for Enphase microinverters), SolarEdge monitoring (for SolarEdge inverters), and manufacturer-specific apps. Your installer should set up monitoring during installation and walk you through how to access it.

Degradation Rates

All solar panels degrade slightly over time, producing marginally less electricity each year. Modern Tier 1 panels typically degrade at 0.25% to 0.5% per year. This means after 25 years, your panels should still produce 87% to 94% of their original output.

This degradation is accounted for in production estimates and warranty guarantees. A panel with a 25-year performance warranty typically guarantees at least 80% to 84.8% of nameplate output at year 25. Some premium panels now offer 30-year warranties with guaranteed output of 88% or higher.

Panel Warranties

Solar panel warranties come in two forms:

Product warranty: Covers manufacturing defects, material failures, and premature degradation. Quality panels offer 25 to 30 year product warranties. This means if a panel fails due to a manufacturing issue within that period, the manufacturer replaces it.
Performance warranty: Guarantees minimum power output over time (typically 25 to 30 years). If a panel's output falls below the guaranteed level due to abnormal degradation, the manufacturer is obligated to repair, replace, or compensate you.

It is worth noting that panel warranties are backed by the manufacturer, not the installer. Even if your installer closes, the manufacturer warranty remains valid. Choose panels from established manufacturers with strong financial stability to ensure they can honour warranties decades from now. See our guide to choosing a solar company in Calgary.

Inverter Warranties

Inverters have different warranty periods depending on the type:

Microinverters: Typically come with 25-year warranties, matching the panel lifespan. Enphase microinverters, for example, carry a standard 25-year warranty.
String inverters: Standard warranties are 10 to 15 years, with options to extend to 20 or 25 years. Since string inverters may need replacement once during the system's life, factor this potential cost into your long-term planning.

Workmanship Warranties

Your installer should provide a workmanship warranty covering the quality of the installation itself, including roof penetrations, wiring, and mounting. Typical workmanship warranties range from 5 to 15 years. This covers issues like roof leaks at attachment points, loose connections, or improperly secured equipment. Ask about the length and scope of the workmanship warranty before signing any contract.

Snow and Winter Considerations

Alberta sees significant snowfall, but snow has less impact on annual production than most homeowners expect. Panels are typically installed at an angle, and their dark surface absorbs sunlight even through thin snow cover, causing snow to melt and slide off relatively quickly. In most cases, panels clear themselves within one to two days after a snowfall.

Manually clearing snow from panels is generally not recommended. Walking on panels can cause microcracks, and the risk of falling off a roof outweighs the production gained from a few days of snow cover. The production estimate your installer provides should already account for snow loss.

Hail Resilience

Alberta is one of Canada's most hail-prone regions, so this is a common concern. Modern solar panels are engineered to withstand significant hail impact. They are tested to IEC 61215 standards, which requires panels to survive 25mm (1-inch) ice balls striking at 23 meters per second. Most quality panels can withstand impacts well beyond this standard.

Your homeowner's insurance policy typically covers solar panels as part of your property. Contact your insurer after installation to ensure your panels are included in your coverage. In most cases, adding solar panels increases your covered property value without a significant premium increase.

Long-Term Maintenance

Solar systems require very little maintenance. There are no moving parts, no filters to change, and no fluids to top up. Occasional visual inspections, monitoring checks, and ensuring vegetation does not grow to shade the panels are generally all that is needed. Professional cleaning is rarely necessary in Alberta, as rain typically keeps panels clean enough for optimal performance.

Key Takeaways

Expect 12,000 to 14,000 kWh per year from a 10 kW system in Calgary
Modern panels degrade at only 0.25% to 0.5% per year
Panel warranties (25-30 years) are backed by manufacturers, not installers
Microinverters offer 25-year warranties; string inverters offer 10-15 years
Snow typically clears on its own and is already factored into production estimates
Panels are engineered to withstand Alberta hail conditions