Quick answer
Solar System A home solar system is the full set of equipment that turns sunlight into electricity your house can use: solar panels, an inverter, mounting hardware, wiring and safety disconnects, and the utility meter, sometimes with a battery.
On this site "solar system" means a solar energy system, not the planets. The panels get the attention, but the other parts decide how much power reaches your outlets, whether it works in an outage and how long it lasts.
Quick facts
The key facts about solar system, with sources:
- Core parts
- Panels, inverter, racking, wiring and disconnects, meter; battery optional 1
- Panels produce
- Direct current (DC) 2
- Inverter converts
- DC to the alternating current (AC) your home uses 3
- Inverter life
- Expected to need replacing at least once over a 25-year array life 1
- Three types
- Grid-tied, hybrid (grid-tied with battery), off-grid
- Size stated as
- kW DC (panels) and kW AC (inverter)
- Installer certification to look for
- NABCEP, the industry-standard certification 4
Key takeaways
- A solar system is more than panels: inverter, racking, wiring, disconnects and meter all matter.
- Most homes use a grid-tied system with no battery. It shuts off in a blackout.
- Add a battery (a hybrid system) if you want backup power.
- The inverter usually wears out before the panels. Plan to replace it once.
- Every line on the contract should name a make, model and size.
What counts as a solar system
The DOE says the panels are only one part of a PV system. The rest is called the "balance of system". That means the racking that holds panels, the inverter that changes the power, and the wires and switches that keep it safe.
A system is sized two ways. The kW DC number adds up the panel ratings. The kW AC number is the inverter’s output limit. Both appear on quotes and utility forms. The DC-to-AC ratio page explains why they differ.
Sources: [1]
How the parts connect
- Sunlight → array of solar panels produces DC
- DC → rapid-shutdown devices and DC wiring → inverter
- Inverter → AC → solar breaker in your main electrical panel
- Main panel → household circuits use solar first
- Surplus → bidirectional utility meter → the grid, or → battery in a hybrid system
Each component, and where it shows up on your contract
| Component | What it does | Contract or permit line to check |
|---|---|---|
| Solar panels (modules) | Turn sunlight into DC electricity | Make, model, wattage, quantity, total kW DC |
| Inverter | Converts DC to AC and talks to the grid; string, micro or hybrid | Make, model, kW AC; warranty years 1 |
| Racking (mounting) | Holds panels to the roof or ground and resists wind | Racking brand; roof attachment and flashing method |
| Rapid shutdown and disconnects | De-energise the array for firefighters and utility crews | Shown on the electrical single-line diagram in the permit set |
| Wiring and conduit | Carry DC from the roof and AC to the panel | Conduit route, often on the permit drawings |
| Main electrical panel | Where the solar breaker lands; may need an upgrade | Any "main panel upgrade" line item |
| Utility meter | Measures power in both directions | Swapped by the utility after approval |
| Monitoring | Reports production by day and panel | App or gateway included, and for how long |
| Battery (optional) | Stores surplus for night or outages | Make, model, usable kWh, backup circuits |
Grid-tied, hybrid or off-grid
Inverter setups compared
| Setup | How it works | Trade-off |
|---|---|---|
| String inverter | One inverter for a string of panels | Lower cost; shade or damage on one panel affects the whole string |
| Microinverters | A small inverter on each panel | Shade on one panel does not drag others down; tends to cost more |
| Power optimizers + string inverter | A device per panel feeding one inverter | A middle path between the two |
| Hybrid inverter | Handles panels and a battery | Needed for many battery setups |
Example: reading the size lines on one quote
Say a quote lists 20 panels rated 435 W each and one inverter rated 7.6 kW AC. The panel rating comes from a current Qcells data sheet 9. The inverter figure is a made-up example for the math.
| Line | Math | What it means |
|---|---|---|
| Panel total (kW DC) | 20 × 435 W = 8,700 W | 8.7 kW DC of panels |
| Inverter (kW AC) | Listed on the quote | 7.6 kW AC maximum output |
| DC-to-AC ratio | 8.7 ÷ 7.6 | About 1.14 |
| Annual production | Modelled from your roof and local weather, in kWh | The number that sets your savings |
A ratio a little above 1 is common, because panels rarely hit full rating. Ask how the annual kWh was modelled. Many installers use NLR’s free PVWatts tool 8.
Where systems are installed
Most home systems sit on a sloped roof on rails. The DOE says arrays are usually tilted near the local latitude and face south in the US for the best yearly output. Panels can also go on a ground mount, a carport or, in some homes, the roofing itself.
Most US systems are tied to the grid. The EIA says that has been true since 2004. Off-grid systems are mainly for cabins and rural homes far from power lines. See our pages on rooftop solar and ground-mount systems.
Benefits and limits of a home solar system
Benefits
- Makes your own power for decades with no fuel.
- Cuts the energy part of your utility bill.
- Little routine care; monitoring flags problems.
- Can grow later with a battery or more panels, if the design allows.
Limits
- A grid-tied system without a battery gives no backup.
- Savings depend on your utility’s export rules.
- The inverter and any battery need replacing before the panels.
- Roof work later means removing and refitting panels.
Limits that shape your system
Outages are the big surprise for many owners. The DOE explains that small home inverters ride through brief grid blips. If the problem lasts or is large, they disconnect and shut down. That protects line workers. It also means no power for you without a battery.
Your utility caps size and sets how exports are paid. Your roof caps how many panels fit. Your main electrical panel may limit how much solar can connect without an upgrade.
Sources: [3]
What drives cost, and which parts wear out first
We do not print one price. The main cost drivers are system size, panel and inverter type, racking, roof condition, any main panel upgrade, permits, labor and any battery. See our solar cost guide and cost by system size.
Panels carry the longest warranties and degrade slowly. The DOE cites a Berkeley Lab survey putting average panel life at 25–35 years in 2025.
Inverters do not last as long: the DOE expects an inverter to be replaced at least once in the 25-year life of an array. The inverter replacement planner helps you time it. Batteries have their own warranties, usually in years and cycles.
The federal 25D homeowner credit ended for property placed in service after 31 December 2025, per the IRS.
How a home solar system is installed
The DOE says systems must meet local building, fire and electrical codes and pass inspection 4. A typical path:
- Check roof suitability and gather 12 months of bills.
- Get several quotes. Ask about the roof, expected kWh, storage and incentives 4.
- Pick an installer. The DOE names NABCEP as the industry-standard certification 4.
- The installer designs the system and applies for permits.
- The installer files the utility interconnection application.
- Crews install racking, panels, inverter and wiring.
- A local inspector checks the work.
- The utility sets the meter and grants permission to operate.
See solar interconnection for the utility step.
Keeping the system running
Watch the monitoring app. Compare each month with the same month last year. A sudden drop usually means an inverter or wiring fault, not dirty panels.
Keep trees trimmed. Look at the array from the ground after storms. Book monitoring help or solar repair if numbers look wrong.
Keep your paperwork: the permit, data sheets, warranties and the utility approval. You will need them to make a claim or sell the house.
Warning signs and when to call a pro
Call your installer or a licensed electrician for any of these:
- The app shows zero or near-zero output on a sunny day.
- An error light on the inverter or a tripped solar breaker.
- Burning smell, scorch marks or buzzing near any part.
- Leaks or stains on the ceiling under the array.
- Your bill jumps with no change in use.
- The monitoring stops reporting. See monitoring shows zero.
Safety rule
Parts of a solar system stay live in daylight even when the inverter is off. Never open boxes or reset equipment beyond what the manual allows. Call a licensed pro.
Codes and rules for a home system
Electrical code. The National Electrical Code (NFPA 70) covers PV in Article 690, grid connection in Article 705 and batteries in Article 706. The 2023 edition rewrote much of 705 and expanded 706, per IAEI. Your state or city adopts an edition.
Building and fire codes. These set roof attachment, load and fire setback rules. South Carolina enforces the 2021 state codes based on the 2021 IRC and IBC.
Utility rules. Each utility sets its own application, size caps and export credits under its state regulator.
Misconceptions about solar systems
- Myth A solar system keeps my lights on in a blackout.
- Reality A grid-tied system without a battery shuts off by design 3.
- Myth The panels are the whole system.
- Reality The inverter, racking, wiring and meter decide much of the result.
- Myth Once installed, it needs nothing for 25 years.
- Reality Expect at least one inverter replacement 1.
- Myth Bigger is always better.
- Reality Utility size caps and export rates can make an oversized system a poor deal.
Who installs which part in South Carolina, and rules in GA and VA
South Carolina splits the work by license. "Solar Panel Installer" is a Residential Specialty registration with the Residential Builders Commission for installing panels and related components; the wiring and connection must be done by a Residential Builder, a licensed residential electrician or a mechanical contractor with the electrical classification 11.
In Virginia, investor-owned utilities allow residential net metering up to 25 kW 12. Georgia Power caps residential renewable systems at 10 kW 13.
Which system fits you
Use these rules of thumb:
- Reliable grid, want lower bills: grid-tied.
- Frequent outages or poor export pay: hybrid with a battery.
- No grid nearby: off-grid, sized for days without sun.
- Unsure: start from 12 months of bills and the size calculator.
Go deeper
Questions about solar system
What are the main components of a home solar system?
Solar panels, an inverter, racking, wiring with disconnects and rapid-shutdown equipment, the connection at your main electrical panel, and a two-way utility meter. A battery is optional. Monitoring is usually included so you can see output by day.
Does a home solar system need a battery?
No. Most home systems are grid-tied with no battery. The grid takes surplus and supplies power at night. A battery adds backup during outages and lets you use more of your own solar. It also adds cost and another part to maintain.
What size solar system does a house need?
It depends on your yearly electricity use, your roof and your local sunlight. Start from 12 months of bills and the system size calculator. Then check your utility’s size cap, which can limit how big you can go.
How long does a home solar system last?
Panels last decades; the DOE cites a 25–35 year average life in 2025. The inverter is the part most likely to be replaced; the DOE expects at least one replacement over a 25-year array life. Batteries have their own warranties.
Does a solar system work during a power outage?
Not a standard grid-tied one. The DOE says small home inverters disconnect and shut down when a grid problem lasts or is large. Backup needs a battery and equipment that can separate your home from the grid.
What is the difference between kW DC and kW AC?
kW DC is the total of the panel ratings. kW AC is the most the inverter can send to your home. Panels rarely reach full rating, so systems often have a bit more DC than AC. Utility forms usually ask for both.
Who installs a home solar system?
A solar company, usually with a licensed electrician for the wiring. The DOE names NABCEP as the industry-standard certification. Check your state’s license rules too; South Carolina, for example, splits panel work and wiring by license type.
Do I need a permit for a solar system?
Almost always. The DOE says systems must meet local building, fire and electrical codes and be inspected. Your installer usually applies for the permits and books the inspection. Your utility must also approve before you switch on.
What is the balance of system?
It is every part of a solar system except the panels. That covers the inverter, racking, wiring, disconnects, monitoring and meter. These parts often affect reliability and cost as much as the panels do.
Sources
- US DOE Solar Energy Technologies Office, Solar Photovoltaic System Design Basics, retrieved .
- US EIA, Solar explained: Photovoltaics and electricity, retrieved .
- US DOE Solar Energy Technologies Office, Solar Integration: Inverters and Grid Services Basics, retrieved .
- US DOE Solar Energy Technologies Office, Homeowner’s Guide to Going Solar, retrieved .
- US DOE Solar Energy Technologies Office, End-of-Life Management for Solar Photovoltaics, retrieved .
- IRS, Residential Clean Energy Credit (§25D), retrieved .
- IAEI Magazine, John Wiles, 2023 National Electrical Code and Photovoltaic Power Systems (23 Mar 2023), retrieved .
- National Laboratory of the Rockies (NLR), PVWatts Calculator, retrieved .
- Qcells, Q.TRON BLK S-G3R.12+/BFG 435–450 W data sheet (2025-08 Rev04), retrieved .
- SC Building Codes Council, code adoption, retrieved .
- SC LLR, Residential Specialty Contractor registration (Solar Panel Installer), retrieved .
- Code of Virginia §56-594 (net energy metering), retrieved .
- Georgia Power, Behind-the-Meter Interconnection Summary for Residential Customers (rev. 15 Aug 2025), retrieved .
Expert review
Written by the HyreSolar Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Component roles, inverter types, outage behavior and the inverter replacement expectation are from the DOE and EIA pages cited. Code articles are from the IAEI 2023 NEC summary.
The South Carolina licensing split is from SC LLR as held in sc-local/facts.js (retrieved 5 Oct 2026); GA/VA limits from verified rows. The example inverter size is illustrative arithmetic, not a recommendation.
Suggest a correction. We fix errors and say what changed.