Understanding Solar Quotes: What the Numbers Actually Mean
Solar proposals are full of acronyms and big numbers. Here's a plain-English guide to understanding exactly what you're being sold.
Understanding Your Solar Quote
Getting a solar quote can feel overwhelming. Here's what each key figure means and what to watch out for.
System Size (kW)
This is the total power capacity of your panels. A typical California home uses a 6–10 kW system. Bigger isn't always better — you want a system sized to your actual usage.
Annual Production (kWh)
This estimate tells you how much electricity your system will generate per year. Compare this to your actual annual consumption (from your utility bills). A well-designed system should offset 80–100% of your usage.
Offset Percentage
The percentage of your electricity bill the solar system is designed to cover. 100% offset sounds great, but over-sizing to achieve it may not be cost-effective if your utility has low buyback rates.
Price Per Watt ($/W)
The standard way to compare solar quotes. In California, $2.50–$3.50/W (before incentives) is typical for quality installations. Be cautious of very low prices — they often mean cheaper equipment or hidden costs.
Payback Period
How long until your energy savings equal what you paid. The California average is 6–9 years. Factor in the 30% federal tax credit (ITC) when calculating this.
Degradation Rate
Panels lose efficiency over time — typically 0.5% per year. A good panel should still produce 87–90% of its original output after 25 years.
Inverter Type
- String inverters: Lowest cost, but the whole string underperforms if one panel is shaded.
- Microinverters: Panel-level optimization, best for complex roofs or partial shade.
- Power optimizers: A middle ground — string inverter with panel-level monitoring.
Pro tip: Always get at least 3 quotes and make sure they're comparing the same system size and equipment brand before choosing based on price.
