Our Methodology
Transparency matters. Learn exactly how our calculator estimates solar production, savings, and system costs for your home.
Data Sources
Solar Irradiance
We use irradiance data from Natural Resources Canada (NRCan) and the European Commission's PVGIS database. These provide location-specific Global Horizontal Irradiance (GHI) and direct normal irradiance data validated against decades of ground station measurements.
Electricity Rates
Electricity rates are sourced directly from provincial utility rate schedules (Ontario Energy Board, Alberta Utilities Commission, etc.). We update rates when new tariffs are published, typically quarterly. Time-of-use rates reflect the current OEB schedule.
System Pricing
Solar system pricing is based on real installer quotes and market data. Our tiered pricing model reflects actual costs for different system sizes, from $5.33/W for 4 kW systems to $3.09/W for 25 kW systems. Prices include equipment, installation, and labour.
Incentives & Rebates
Incentive data is sourced from official government program websites (Canada.ca, provincial energy ministries, municipal CEIP programs). We verify and update this information regularly, noting that programs can change without notice.
Calculation Methodology
Solar Production Estimate
Our production model accounts for:
- Local solar irradiance (kWh/m²/year) based on geographic coordinates
- Panel orientation (tilt and azimuth) — south-facing at roof pitch is default
- Panel efficiency and degradation (0.5% annual degradation from rated 22.5%)
- Temperature derating (-0.30%/°C above 25°C cell temperature)
- System losses (inverter efficiency ~97%, wiring ~2%, soiling ~2%)
- Snow loss modeling (province-specific, 2-8% annual reduction)
- Bifacial gain (5-10% for roof-mounted installations)
Savings Calculation
Savings depend on your system type:
- Zero-Export: All production is self-consumed, offsetting grid purchases at the retail rate
- Net Metering: Self-consumed energy offsets at retail rate; exported surplus earns credits at the applicable export rate
- Peak Shaving: Battery charges during low-rate periods and discharges during peak, maximizing time-of-use arbitrage
Roof Analysis
Our satellite-based roof analysis includes:
- Roof area measurement from satellite/aerial imagery
- 10% obstruction allowance for vents, chimneys, and access requirements
- Shading factor based on user-reported conditions (none to significant)
- Panel spacing calculations (2.5 cm gaps for thermal expansion and safety)
- Maximum panel count constrained by usable roof area
Financial Modeling
Financial projections use:
- Tiered system pricing based on actual market rates
- 3% annual electricity rate escalation (conservative estimate)
- 0.5% annual panel degradation
- All applicable federal and provincial incentives
- 25-year analysis period matching typical panel warranty
Accuracy & Limitations
Our production estimates are typically within 5-10% of actual annual output for properly installed systems. Key limitations include:
- Shading from nearby trees or buildings that grow or are built after estimation
- Unusual weather years that deviate significantly from historical averages
- System-specific factors like inverter clipping or wiring variations
- Changes to electricity rates or incentive programs after estimation
For the most accurate estimate, we recommend using our detailed estimator tool which considers your specific address, roof dimensions, and utility bill data.
Frequently Asked Questions
Related Resources
Solar Calculator
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Learn moreHow It Works
Learn how solar energy powers your home.
Learn moreSolar Panel Cost
See current system pricing.
Learn moreSolar Energy Maps
View solar irradiance data for Canada.
Learn moreFAQs
Common questions about solar energy.
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