Your Complete Guide to Solar Energy
Everything you need to know before going solar
Whether you're exploring solar for the first time or comparing quotes, this guide covers how solar works, what it costs, how to choose the right system, and what to look for in an installer. We take a global perspective so the information applies wherever you are.
How Solar Works
Solar panels are made up of photovoltaic (PV) cells, typically manufactured from silicon. When sunlight hits these cells, photons knock electrons free from atoms in the silicon, creating an electrical current. This is called the photovoltaic effect, and it produces direct current (DC) electricity. A typical residential panel contains 60 to 72 cells and generates between 350 and 450 watts under ideal conditions.
Since most homes and appliances run on alternating current (AC), your solar system includes an inverter that converts DC to AC. There are two main types: a string inverter, which connects all panels in series to a single unit, and microinverters, which attach to each individual panel and convert power at the source. Microinverters are more expensive but perform better when panels face different directions or are partially shaded.
Most residential solar systems are grid-connected, meaning they remain tied to the local electricity grid. When your panels produce more than you use, the excess is exported to the grid and you may receive a credit or payment through net metering or a feed-in tariff. When the sun is not shining, you draw power from the grid as usual. Off-grid systems are fully independent but require substantial battery storage and are typically used in remote areas without reliable grid access.
Modern solar panels are sleek, efficient, and built to last 25+ years.
Is Solar Right for You?
Solar works best on roofs that receive good, unobstructed sunlight for most of the day. Here are the key factors that affect your roof's suitability:
Roof Type Considerations
Your roof material significantly affects the installation process, cost, and choice of mounting system. Most roof types are suitable for solar, but each requires a different approach. Here is what to expect for common roofing materials.
Thatched and heritage roofs are generally not suitable for standard solar panel installations. Thatched roofs cannot support mounting hardware, and heritage-listed buildings often have strict planning restrictions. In these cases, solar tiles (BIPV) may be an option, or ground-mounted systems can be considered as an alternative. Always check with your local planning authority before proceeding.
Panel Placement & Orientation
How your panels are positioned on the roof has a major impact on energy production, self-consumption, and overall system value. Getting placement right is one of the most important aspects of system design.
Tip: Ask your installer for a detailed production estimate that accounts for your specific roof orientation, tilt, and shading. Reputable installers will provide a simulation showing expected monthly output, not just an annual total. This helps you understand seasonal variation and set realistic expectations.
Choosing the Right System Size
The right system size depends on your electricity consumption, roof space, budget, and goals. Start by reviewing your electricity bills to understand your average daily usage in kilowatt-hours (kWh).
Typical daily household usage varies widely by country and household size. In Australia, the average is around 16-20 kWh/day. In the US, it is around 29 kWh/day. In the UK, it is closer to 8-10 kWh/day. These averages include all seasons, so check your summer and winter bills separately.
As a rough rule, each 1kW of solar panels produces approximately 3.5 to 5.0 kWh per day, depending on your location's solar irradiance. A 6.6kW system in a sunny climate might produce 25-30 kWh/day, while the same system in a cloudier region might produce 15-20 kWh/day.
| System Size | Panels (approx.) | Daily Output* | Best For |
|---|---|---|---|
| 3kW | 7-8 | 10-15 kWh | Small households, low usage, limited roof space |
| 5kW | 12-13 | 17-25 kWh | Average 2-3 person household |
| 6.6kW | 15-18 | 22-33 kWh | Most popular size; typical family home |
| 10kW | 24-27 | 33-50 kWh | Large households, EV owners, pools, high usage |
| 13-15kW | 32-40 | 44-75 kWh | Very high usage, future battery or EV plans |
* Output varies by location, season, orientation, and shading. Figures based on 3.5-5.0 kWh per kW per day.
When in doubt, size up. Solar panel prices have dropped significantly, and the marginal cost of adding a few extra panels is small compared to the cost of a second installation later. Oversizing also gives you headroom for future additions like battery storage, an electric vehicle, or a heat pump.
Solar Panel Types
There are three main types of solar panel technology used in residential and commercial installations. Each has trade-offs in efficiency, cost, and appearance.
Our recommendation: For most residential installations, monocrystalline panels offer the best balance of efficiency, longevity, and value. The price gap with polycrystalline has narrowed significantly, making mono the default choice for most installers worldwide.
Solar Tiles & Building-Integrated PV
Building-integrated photovoltaics (BIPV) replace conventional roofing materials with solar-generating surfaces. Instead of mounting panels on top of your existing roof, solar tiles and shingles become the roof itself. While significantly more expensive than traditional panels (typically 2-3x the cost), they offer a seamless aesthetic that is virtually indistinguishable from standard roofing.
Solar tiles are best suited for new builds or homes that already need a full roof replacement, where the incremental cost over standard roofing plus traditional panels is more manageable. Per square metre, they are generally less efficient than conventional panels, but because they can cover a larger proportion of the roof area, total system output can still be competitive.
Popular Solar Tile Products
Advantages
- Seamless, aesthetically superior appearance
- No mounting rails or visible racking
- Doubles as roofing material — replaces tiles/shingles
- HOA-friendly and heritage-area compatible in some regions
- Can cover more of the roof area than traditional panels
Disadvantages
- Significantly higher cost (2-3x traditional panels)
- Fewer qualified installers available
- Longer installation time (full roof, not just panels)
- Harder to expand or modify system later
- Lower efficiency per square metre than conventional panels
Battery Storage
A home battery stores excess solar energy generated during the day so you can use it in the evening, at night, or during a power outage. While solar panels alone save money by offsetting daytime usage, a battery lets you maximise self-consumption and reduce your reliance on the grid even further.
Batteries make the most financial sense when electricity prices are high, feed-in tariffs are low, time-of-use tariffs are in effect (making evening electricity expensive), or when you want backup power during outages. In areas with generous net metering, the financial case for batteries is weaker since the grid effectively acts as free storage.
System Configurations
Popular Battery Brands
| Brand | Popular Model | Capacity | Key Feature |
|---|---|---|---|
| Tesla | Powerwall 3 | 13.5 kWh | Integrated inverter, whole-home backup |
| Enphase | IQ Battery 5P | 5 kWh (stackable) | Modular, pairs with Enphase microinverters |
| BYD | HVM / HVS | 5.1-22.1 kWh | Highly scalable, wide inverter compatibility |
| sonnen | sonnenBatterie | 5-15 kWh | German engineering, integrated energy management |
| SolarEdge | Home Battery | 9.7 kWh (stackable) | Integrates with SolarEdge optimisers |
Battery storage lets you use solar energy around the clock, not just when the sun is shining.
Understanding Costs & ROI
Solar system costs vary significantly by country, system size, panel quality, and installer. Prices have dropped dramatically over the past decade and continue to fall. The figures below are rough guides for a typical 6-7kW residential system, including installation, before any rebates or incentives.
| Country | Typical Cost (6-7kW) | Payback Period | After Incentives |
|---|---|---|---|
| Australia | A$5,000 - $9,000 | 3-5 years | STCs reduce cost by ~$2,500-$3,500 |
| United States | US$12,000 - $18,000 | 6-9 years | 30% federal tax credit (ITC) |
| United Kingdom | £5,000 - £9,000 | 8-12 years | 0% VAT on residential solar |
| Canada | C$15,000 - $22,000 | 8-12 years | Greener Homes Grant + provincial programs |
| New Zealand | NZ$12,000 - $18,000 | 7-10 years | Limited incentives; savings from self-consumption |
Factors that affect your ROI: electricity prices (higher prices = faster payback), sunlight hours, system size and quality, self-consumption rate (using solar power directly vs exporting), feed-in tariff rates, and financing costs if you take a loan.
Financing options vary by country but commonly include cash purchase (best ROI), solar loans (own the system, pay over time), leases and power purchase agreements (PPAs) in some markets, and government low-interest loan schemes. Cash purchase typically delivers the best long-term return, but solar loans can make the investment accessible with positive cash flow from day one in many cases.
Professional installation ensures your system performs safely and at peak efficiency.
How to Choose an Installer
Your installer is just as important as the equipment they use. A quality installation ensures maximum performance, safety, and warranty protection. Here is what to look for:
Accreditations & Certifications
Look for industry-recognised certifications. In Australia, this means CEC (Clean Energy Council) accreditation. In the US, look for NABCEP certification. In the UK, MCS (Microgeneration Certification Scheme) certification is essential. In Canada, look for CanSIA membership. These accreditations ensure the installer meets quality and safety standards.
Reviews & Reputation
Check online reviews on Google, product review sites, and solar forums. Look for patterns in reviews rather than focusing on individual ratings. Ask the installer for references from recent customers. A reputable installer should be happy to provide them.
Warranties
Understand the different warranties: panel product warranty (typically 12-25 years), panel performance warranty (25-30 years), inverter warranty (5-25 years), and the installer's workmanship warranty (typically 5-10 years). Get everything in writing.
Experience & Track Record
How long have they been in business? How many systems have they installed? Do they specialise in residential, commercial, or both? An experienced installer is more likely to handle unexpected challenges during installation and provide better system design.
Multiple Quotes
Always get at least 3 quotes. Compare not just price but also equipment quality, system design, estimated output, and warranty terms. The cheapest quote is rarely the best value. Be wary of quotes that seem significantly below market rates.
Equipment Brands
Ask which panel and inverter brands they use. Quality installers typically offer tier-1 panels from established manufacturers. Beware of installers pushing unknown brands with unusually low prices — warranty claims can be difficult if the manufacturer exits the market.
Solar Incentives Overview
Governments worldwide offer a range of incentives to encourage solar adoption. These can significantly reduce the upfront cost of going solar and improve your return on investment. Incentives vary widely by country, state, and even local council, so it is important to check what is available in your area.
Common types of incentives include upfront rebates and grants (reducing purchase price), tax credits (reducing your tax bill), feed-in tariffs (payment for exported electricity), renewable energy certificates (tradable credits), low-interest loans, and zero-interest financing schemes.
Frequently Asked Questions
How long do solar panels last?
Most solar panels are warranted for 25 to 30 years, but they can continue producing electricity well beyond that. After 25 years, panels typically still operate at around 80-85% of their original capacity. The inverter usually needs replacing once during the panel lifespan, typically after 10-15 years for string inverters (microinverters can last 25+ years).
Do solar panels work on cloudy days?
Yes, solar panels still generate electricity on cloudy days, though at reduced output — typically 10-30% of their rated capacity depending on cloud thickness. They work with light, not direct sunlight. Even in overcast climates like the UK or northern Europe, solar panels produce meaningful amounts of energy over the course of a year.
How much can I save with solar?
Savings depend on your electricity usage, local electricity prices, system size, sunlight hours, and any feed-in tariff or net metering credits. Most homeowners save between 50-90% on their electricity bills. In high-electricity-cost areas like Australia, California, or Germany, payback periods can be as short as 3-5 years, with decades of savings thereafter.
What happens during a power outage?
Standard grid-connected solar systems shut down during a power outage for safety reasons — this prevents electricity from feeding back into the grid and endangering utility workers. If you want backup power during outages, you need a battery storage system with backup capability, or a hybrid inverter that can create a local microgrid.
Can I add batteries later?
Yes, in most cases you can retrofit a battery to an existing solar system. However, it is simpler and often more cost-effective if your system is designed with battery compatibility from the start. Check that your inverter is battery-ready or consider a hybrid inverter when initially installing solar if you think you may want batteries in the future.
How long does installation take?
A typical residential solar installation takes 1-3 days for the physical work. However, the overall process — from signing a contract to turning on the system — usually takes 4-12 weeks, depending on permit approvals, utility interconnection agreements, and installer availability. Larger commercial systems can take several weeks to install.
Do I need planning permission for solar panels?
In many countries, rooftop solar panels fall under permitted development and do not require planning permission, provided they meet certain conditions (e.g., not protruding too far, not on a listed building). However, rules vary by country and local authority. Ground-mounted systems, heritage areas, and conservation zones often have stricter requirements. Always check with your local planning authority.
What maintenance do solar panels need?
Solar panels require very little maintenance. Rain typically keeps them clean enough, but an annual visual inspection is recommended. In dusty areas or where panels are installed at a low angle, occasional cleaning with water and a soft brush can improve output by 5-10%. You should also have your inverter and wiring inspected every few years by a qualified electrician.
Will solar panels damage my roof?
When installed correctly by an accredited installer, solar panels should not damage your roof. In fact, they can protect the area of roof they cover from weather. The mounting system is designed to be watertight. However, it is important that your roof is in good condition before installation — any existing issues should be repaired first.
Can I take solar panels with me if I move house?
While technically possible, removing and reinstalling solar panels is expensive and rarely worthwhile. Solar panels typically increase your property value by more than their removal cost. Most homeowners leave the system in place and factor the added value into their sale price. Some studies show homes with solar sell faster and for a premium.
What is net metering and how does it work?
Net metering (or feed-in tariffs in some countries) is a billing arrangement where excess electricity your solar panels produce is exported to the grid, and you receive a credit or payment for it. When your panels produce less than you need (e.g., at night), you draw from the grid as normal. This effectively lets the grid act as a battery. Policies and rates vary significantly by country and utility.
Are solar panels recyclable?
Yes, solar panels are recyclable. Most of a panel (glass, aluminium frame, wiring) is easily recyclable. The silicon cells require more specialised processing. In the EU, manufacturers are required to take back and recycle panels under the WEEE directive. Recycling programs are expanding worldwide as the first generation of panels reaches end-of-life.
Ready to go solar?
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