How Home Solar Works, From Roof to Meter

Each panel is a grid of silicon cells behind tempered glass. When sunlight hits a cell, it knocks electrons loose and pushes them through wiring as direct current. More light means more current, which is why orientation, tilt and shade matter so much.

Most residential panels today are rated around 400–450 watts each under standard test conditions. That rating is a lab number. Real output depends on sun angle, temperature, dust, snow and shade. You’ll see the whole range in your monitoring app over a year.

Your home and the grid run on alternating current, so the DC has to be converted. There are a few common ways to do it, and the right one depends on your roof and whether a battery is in the plan.

Microinverters, like Enphase’s, put a small inverter under each panel, so each panel works independently. That helps on roofs with partial shade or several orientations. A hybrid inverter, like the one built into Tesla’s Powerwall 3 or Sigenergy’s SigenStor, takes DC from the panels and the battery in one box, so solar can charge the battery without an extra conversion. Traditional string inverters, one central box for the whole array, are the older third approach.

Solar power flows to whatever is running in your home right now: the fridge, the furnace blower, the EV charger. You don’t flip anything; the physics handles it. Only when production exceeds what the house is using does power flow out through the meter.

This is why timing matters. A household that runs laundry and charges the car at midday uses more of its own solar directly. On utilities that credit exports at less than the retail rate, like Longmont’s value-of-solar credit or Fort Collins’ time-of-day credit, using solar directly is worth more than exporting it.

Your utility replaces or reprograms your meter so it counts power in both directions. What happens to exported power depends entirely on who your utility is. That’s the biggest reason a Denver system and a Fort Collins system have different economics.

Xcel Energy customers get kilowatt-hour credits that roll forward month to month. Colorado Springs Utilities approved a new structure for new solar customers in September 2026. Co-ops and municipal utilities each set their own terms within state law. We walk through your utility’s rules before you sign anything.

When the grid goes down, a standard grid-tied inverter stops within a fraction of a second. It has to. Otherwise it would push power onto lines that utility crews expect to be dead. National interconnection standards require this “anti-islanding” behavior, so solar alone won’t keep your lights on during a storm outage or a wildfire safety shutoff.

A battery changes that. With a battery and the right switching equipment, your home disconnects from the grid automatically and runs as a small island: the battery covers the evening, and the panels recharge it the next day. After Xcel’s wildfire shutoffs in December 2025 and March 2026, that’s why so many Front Range homeowners are asking about batteries.

Systems built on Tesla, Enphase or Sigenergy equipment come with the maker’s monitoring app. It shows production, home use and grid flow, down to the individual panel on microinverter systems. Glance at it now and then, and especially after hail or heavy snow.

The utility bill is the other check. Once your net-metering account is set up, you’ll see exported energy and credits on each statement. Our bill-reading guide shows where to find them.