A modern rooftop solar system converts sunlight into usable AC electricity for household appliances, feeds excess into the grid, and optionally stores energy in batteries for night use. This guide walks the technology, the economics, and the practical questions homeowners face.
Home solar has moved from a niche curiosity to a routine building product in most sunny markets. The technology is settled; the interesting decisions are now sizing, batteries, and export tariffs. This guide covers what actually happens when a home has solar.
The core components
| Component | Purpose |
|---|---|
| Solar panels (modules) | Convert sunlight to DC electricity |
| Inverter | Convert DC to AC usable by home appliances and grid |
| Mounting system | Attach modules to roof or ground |
| DC and AC electrical wiring | Carry current between components |
| Isolators and safety switches | Allow safe shutdown |
| Battery (optional) | Store energy for later use |
| Monitoring system | Track production and consumption |
| Meter | Measure grid import and export |
How the system works day to day
Sunlight hits the panels. Photovoltaic cells convert photons into DC electric current. The inverter converts DC to AC synchronised with the grid frequency. During daylight, the home consumes solar generated electricity first; excess goes to the grid (or battery). At night, the home consumes battery or grid electricity. Everything happens automatically.
Sizing the system
System size is measured in kilowatts DC (kW). A typical residential system is 3 to 10 kW. The right size depends on annual electricity consumption, roof space, budget, and grid feed in rules. Common approach: install to cover annual consumption if roof and budget allow.
| Home size and consumption | Suggested system size |
|---|---|
| Small, 3000 to 4500 kWh per year | 3 to 4 kW |
| Medium, 4500 to 7000 kWh per year | 5 to 7 kW |
| Large, 7000 to 10000 kWh per year | 7 to 10 kW |
| All electric with EV | 10 to 15 kW plus battery |
How much electricity you actually generate
A 5 kW system in London produces roughly 4,500 kWh per year; in Los Angeles roughly 8,500 kWh per year. Panel orientation, tilt, and shading affect the actual output. Online solar potential estimators from national labs (NREL PVWatts, EU JRC PVGIS) give location specific numbers. See EU JRC PVGIS tool.
Battery storage: is it worth it
Home batteries let you use solar energy at night. Typical residential batteries range from 5 to 15 kWh capacity. The economic case depends on the difference between import and export tariffs.
| Scenario | Battery makes sense when |
|---|---|
| High import rate, low export rate | Store to self consume |
| Time of use tariff | Store cheap grid and use peak |
| Frequent outages | Backup power value |
| Off grid | Necessary for continuous supply |
| Simple net metering | Battery not economically necessary |
Grid connection and export
In most markets, homes with solar are grid connected and can export surplus back. Export tariffs vary widely:
- Net metering: exported units offset imported units on the bill.
- Feed in tariff: fixed rate paid per kWh exported (rare now).
- Smart export tariff: dynamic price based on time and grid conditions.
- Zero export: some grids charge for exports rather than credit them.
Costs
| Item | Typical cost (2026) |
|---|---|
| Panels | USD 300 to 500 per kW |
| Inverter | USD 100 to 200 per kW |
| Mounting and wiring | USD 200 to 400 per kW |
| Installation labour | USD 300 to 800 per kW |
| Battery (per kWh capacity) | USD 400 to 700 |
| Permits and inspection | USD 300 to 1500 |
| Total system (5 kW without battery) | USD 6,000 to 12,000 |
Payback period
Payback ranges from 4 years in favourable markets (high sun, high tariffs, incentives) to 12 years in less favourable ones. Systems last 25 to 30 years with panel degradation of about 0.5 percent per year. Batteries last 10 to 15 years.
Installation process
- Site assessment: roof, shading, structure.
- System design and quotation.
- Permit application to local authority.
- Utility interconnection application.
- Installation (typically 1 to 3 days).
- Inspection and commissioning.
- Grid connection approval.
- System online and monitored.
Maintenance
Solar systems are largely maintenance free. Panel cleaning improves output modestly. Inverter life is typically 10 to 15 years. Monitoring system data catches performance issues early.
Policy and incentives
Many jurisdictions offer solar incentives: tax credits (US 30 percent Inflation Reduction Act residential), feed in tariffs, low interest loans, rebates. The US DOE solar programme maintains the residential incentive landscape.
Global scale of home solar
Rooftop solar globally exceeds 350 GW of installed capacity, with Australia (highest per capita), Germany, and California among leaders. Emerging markets are catching up rapidly. Community solar (shared installations for people without suitable rooftops) is growing.
Frequently asked questions
Do solar panels work in cloudy weather?
Yes, at reduced output. Modern panels generate 10 to 30 percent of rated output on cloudy days.
Do panels need to face south?
Optimum yes in the Northern Hemisphere. East and west orientations produce 80 to 90 percent of south facing output.
What if it hails?
Standard panels are tested for hail impacts. Very large hail can damage panels; insurance typically covers.
Can I go off grid?
Technically yes, but requires large battery and generator backup. Grid connected is far more economic for most homes.
Are batteries safe?
Modern lithium ion batteries with proper installation are safe. Fire risk is very low with certified equipment.
How long do panels last?
25 to 30 years with about 0.5 percent per year degradation. Older panels still work; output declines.
Should I lease or buy?
Buying is typically better economics if you can afford upfront. Lease and PPA options exist for zero upfront.
What about roof orientation and pitch?
Panels can be tilted independently of roof pitch if needed. Non ideal orientations still work, just at lower output.
Does solar increase home value?
Studies show yes, roughly 3 to 4 percent higher sale prices for solar equipped homes.
What is the best time to install?
Depends on incentive schedules and installer availability. Winter is often lower demand for installers with better pricing.
Summary
Home solar has become a mature product. The technology is settled: panels convert sunlight to DC, inverters convert DC to AC, batteries optionally store excess. The interesting decisions are sizing, battery inclusion, and grid connection terms. Payback ranges from 4 to 12 years depending on region and tariffs. For homes with suitable roof and enough sun, home solar is now one of the most economically compelling home investments available.
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