A solar panel turns sunlight into DC electricity in a silicon cell. An inverter converts that DC into the AC your home uses. Whatever you do not burn yourself flows back to the grid, where net metering credits it against the power you import later. That is the whole loop in two sentences. The rest of this article unpacks each step in plain English, so you can read any proposal and know what is actually being described.
The photovoltaic cell: where electricity is born
A solar panel is made of photovoltaic cells, usually 60 to 96 of them per panel. Each cell is a thin slice of silicon, a semiconductor with a useful property: when photons of light hit it, they knock electrons loose. Those electrons are channeled into a circuit, and that flow is electricity.
The output is direct current, or DC. It flows in one direction like the current from a battery. DC is how the panel produces power, but it is not how your home uses it. Your appliances, lights, and outlets all run on alternating current, AC, which is what the utility grid delivers. Converting DC to AC is the inverter's job.
Each individual cell produces about 0.5 volts. Sixty cells wired in series produce about 30 volts. Multiple panels wired together produce enough voltage and current to meaningfully power a home. A typical residential system is 20 to 30 panels producing 8 to 12 kilowatts of peak capacity. That capacity is the rate at which the system can produce power under ideal conditions. What matters for your bill is how many hours of useful sunlight per day that capacity actually sees.
The inverter: brain of the system
The inverter takes DC electricity from the panels and converts it into AC that your home and the grid can use. It is sophisticated electronics, not a simple converter — it synchronizes its output to the grid's 60 Hz frequency and voltage, monitors system health, and protects the system when the grid goes down.
There are three main inverter types, and the choice matters more than most homeowners realize.
String inverters wire all the panels together in series, and one central inverter handles the whole system. They are cheaper and simpler, but a panel that is shaded or underperforming can drag down the whole string. Think of Christmas lights wired in series — one weak bulb affects the rest.
Microinverters, dominated by Enphase, mount one small inverter on the back of each panel. Each panel operates independently, so a shaded panel only loses its own output. Microinverters cost more but perform meaningfully better on complex roofs with shading or multiple orientations. They also carry 25-year warranties that match panel timelines.
Power optimizers, dominated by SolarEdge, are a middle ground. Panel-level electronics optimize each panel's DC output before sending it to a central inverter — better shade tolerance than a pure string system, less expensive than full microinverters. Whichever type an installer proposes, ask why.
From the inverter into your home and the grid
Once the inverter produces AC, it flows through your home's main electrical panel — the breaker box — and powers whatever is running. Refrigerator, HVAC, lights, dryer. Solar and grid electricity mix seamlessly. Your home draws from solar first and pulls from the grid only when solar production falls short of demand.
That leaves the surplus. On a sunny weekend afternoon your panels might be producing 6 kW while your home is using 1 kW. The other 5 kW flow back through your meter to the grid. In most states, net metering policies give you a credit for that exported electricity. Your meter literally runs backward while you are exporting. At night, on cloudy days, or whenever demand exceeds production, your home draws from the grid and those credits offset what you owe. At the end of each billing period you pay the net difference.
This is why the grid is your battery is a common phrase. You are banking excess daytime production as credits and spending them at night. The catch is that your credits may be valued at full retail rate, as in many traditional net metering states, or at a much lower export rate. California's NEM 3.0 cut export credits significantly, which is one reason home battery storage has become much more popular in that market.
How much electricity a system actually produces
This is where it gets concrete and where Solrova's approach diverges from most proposals. Many pitches express production as an offset percentage — "this system will offset 87% of your usage." That number sounds reassuring, but it is circular: it depends on your current usage, which can shift up or down year to year.
The more useful number is raw kWh production. The formula is straightforward:
System size (kW) × peak sun hours per day × 365 days × derate factor = annual kWh production.
For an 8 kW system in Phoenix, with about 5.8 peak sun hours per day and a 0.86 derate factor, the math runs 8 × 5.8 × 365 × 0.86, which equals roughly 14,590 kWh per year. That is a concrete, verifiable number. If your household uses 12,000 kWh per year, this system produces more than you need. If you use 18,000 kWh, it is not enough. The math is transparent and every input is something you can challenge.
The derate factor — typically 0.80 to 0.87 — accounts for real-world efficiency losses: inverter efficiency, wiring losses, dust accumulation, panel temperature effects, and slight degradation over time. It is not pessimism. It is honesty about what a system produces in the field versus what it would produce in lab conditions on a perfect cloudless day. Every honest proposal should show you the system size, the peak sun hours used, and the derate factor. If any of the three is missing, ask.
What changes the output number
Four variables determine your system's output more than anything else.
Peak sun hours. This is not daylight hours. It is a measure of solar irradiance — the intensity of sunlight reaching your roof normalized to the equivalent of full-noon-sun hours per day. Phoenix gets about 5.8. Seattle gets about 3.5. The same 8 kW system on the same roof produces about 14,600 kWh per year in Phoenix and about 8,900 kWh per year in Seattle. This is the single biggest variable in solar economics.
Roof orientation and tilt. A south-facing roof at roughly a 30-degree pitch captures the most sunlight in the U.S. East- and west-facing roofs capture about 10–20% less, though west-facing roofs can be more valuable in time-of-use utility markets because they produce in the late afternoon when grid rates peak.
Shading. Trees, chimneys, neighboring buildings, and even your own roof's dormers can reduce output significantly. Partial shading on a string-inverter system can drop output 20–30%. Microinverters and power optimizers limit the damage to the shaded panels only.
Panel efficiency and degradation. A 400-watt panel produces 400 watts under standard test conditions. Over 25 years, panels typically degrade about 0.5% per year, leaving year-25 output at roughly 88% of year one. This is normal and is already priced into the manufacturer's warranty.