What is the photovoltaic effect that makes panels work?
The photovoltaic effect is sunlight knocking electrons loose inside a solar cell so they flow as electricity. A solar cell is mostly silicon, the same element in beach sand and computer chips. Manufacturers add tiny amounts of other elements to create two layers: one with extra electrons (the n-type layer) and one with room for electrons (the p-type layer). Where those layers meet, an electric field forms, like a one-way gate for electrons.
When a particle of light (a photon) hits the silicon with enough energy, it bumps an electron free. The built-in electric field pushes that loose electron in one direction, and the metal contacts on the cell collect it. Connect a wire and those moving electrons become usable current. That is the whole trick: light goes in, electrons move, and you have a small voltage from a single cell, which is why panels wire dozens of cells together.
What happens between the panel and your wall outlet?
Between the roof and your outlets, the DC power from your panels gets converted to AC and routed into your home's electrical panel. Solar panels produce direct current (DC), where electrons flow one way, but your home runs on alternating current (AC), where the flow reverses 60 times a second. The device that bridges them is the inverter, and it is the brain of a solar system. If you want the deeper tradeoff here, see string inverter vs microinverter.
A string inverter sits on a wall and converts the combined output of many panels at once, while microinverters bolt under each panel and convert on the spot. Either way, the AC output feeds your home's main electrical panel. Your appliances pull from it first, and anything left over flows out to the grid (or into a battery if you have one). The difference between power (kW) and energy (kWh) matters a lot here, so it helps to read kW vs kWh before you size anything.
What are the parts of a solar power system?
A grid-tied solar system has four core parts: panels, an inverter, a meter, and your existing electrical panel. The panels capture light and make DC. The inverter turns that DC into household AC. A bidirectional meter counts energy flowing both into your home and back out to the grid, which is how net metering credits get tracked. Your existing main panel distributes the power to circuits, exactly as it did before solar.
Two optional parts change what the system can do. A battery stores excess daytime production so you can use it at night or during an outage, and racking or mounting hardware fixes the panels to your roof or the ground at the right tilt. If you are weighing storage, our roundup of the best solar battery backup for home walks through real options. Without a battery, a standard grid-tied system shuts off in a blackout for safety, so storage is what keeps the lights on.
How much electricity does a solar panel actually make?
A modern residential panel is rated around 400 to 450 watts under standard test conditions, but real output is lower and changes all day. Rated wattage is measured in a lab at full sun and a set temperature. In your yard, output rises and falls with the sun's angle, cloud cover, shade, panel temperature, and the time of year. Panels actually lose a little efficiency as they get hot, so a blazing summer afternoon is not their absolute peak.
What matters for your bill is energy over time, measured in kilowatt-hours. The rough rule is that each kilowatt of panels produces roughly 1,200 to 1,700 kWh per year depending on your location and roof. To turn that into a panel count for your own usage, run our solar panel calculator or read how many solar panels to power a house. Cold and even winter sun still work, which we cover in do solar panels work in winter.
Do solar panels work on cloudy days or at night?
Solar panels work on cloudy days, just at reduced output, and they make nothing at night. Panels respond to light, not heat, so on an overcast day they typically produce roughly 10 to 25 percent of their clear-sky output because diffuse light still reaches the cells. A bright winter day can outperform a hazy summer one. They simply need photons, and clouds scatter rather than block all of them.
At night there is no sunlight, so production drops to zero. This is exactly why batteries and the grid matter: a grid-tied system without storage runs your house on solar by day, banks any surplus as net-metering credits, and pulls grid power after dark. Add a battery and you store your own daytime energy to cover the night instead of buying it back. The panels themselves never change; the rest of the system decides what happens when the sun is down.
Frequently asked questions
What are solar panels made of?
Most residential solar panels are made of crystalline silicon cells wired together behind tempered glass, sealed in a weatherproof backing and held in an aluminum frame. The silicon is what generates the current, and the glass and frame protect it for decades outdoors. You will see two main cell types, monocrystalline and polycrystalline, compared in our monocrystalline vs polycrystalline guide.
Do solar panels store electricity by themselves?
No, a solar panel does not store any electricity on its own. It only produces power while light is hitting it, and that power must be used immediately, sent to the grid, or stored in a separate battery. If you want energy available at night or during an outage, you need a battery added to the system.
Why do solar panels need an inverter?
Solar panels produce direct current (DC), but homes and the grid run on alternating current (AC), so an inverter is required to convert between them. Without an inverter, the panel's output could not power standard appliances or feed the grid. The inverter also handles safety functions like shutting down during a grid outage.
How long do solar panels last?
Most solar panels are built to last 25 to 30 years or more, and many manufacturers warranty around 80 to 90 percent of original output at year 25. Output declines slowly, often less than half a percent per year, rather than failing all at once. Inverters usually have shorter lifespans and may need replacement once during a panel's life.
Can I still get a federal tax credit for buying solar in 2026?
No, the 30 percent federal residential solar tax credit (Section 25D) expired for systems placed in service after December 31, 2025, so a homeowner who buys a system now gets no federal residential credit. Leases and power purchase agreements are different because the system owner can still claim a commercial credit through 2027, which may lower what you pay. To weigh those paths, see our solar lease vs buy comparison, and check the disclaimer for the limits of this general information.