Question: How many solar panels can fit on my roof and how much will the system produce?
Answer: Though every residential roof is different, here are some simple guidelines to get you started.
1. Solar panel’s DC power rating equals approximately 15 watts/square foot.
2. 70% of roof space is typically usable for panels.
3. In good conditions (no shading and southern orientation), St. Louis region solar systems produce approximately 4 kilowatt-hours per day for each kW installed (more in sunnier months and less in winter).
4. Most homeowners choose a 2 to 10 kW system that balances their goals including: budget, energy production, and roof space.
Available roof space: 15 X 20 feet = 300 ft2
Usable roof space: 300 ft2 X 70% = 210 ft2
Solar on roof: 210 ft2 X 15 watts/ft2 = 3,150 watts (3.15 kW)
Production: 3kW X 4 hours = 12 kWh/day = 4,380 kWh/year
Answer: The main threat to panels is weather, with the primary concern of hail. All the panels StraightUp Solar installs have a minimum impact testing and warranty for one-inch hail at fifty mph.
The second component of durability addresses the life of the solar panels and how much power they will produce. All panels that we offer have a minimum 25-year power production warranty that guarantees 80% production. We typically estimate panel production degradation at 0.5% per year when calculating production over the lifetime of the panel.
Many solar panels installed in the 1980’s are still producing clean kilowatt-hours! It’s safe to say that solar panels are one of the most durable, long-lasting investments that you can make for your home or business.