Solar Panels: Your Comprehensive Guide

How to compare Solar Panels

When you start getting quotes for solar panels for your home, it's useful to learn some terms to help you make decisions and ensure you're getting the best solar system for your home.

Solar Panel Wattage

Panel wattage refers to the amount of electrical power that a solar panel can produce. It's measured in watts (W) and indicates the panel's capacity to generate electricity.

The wattage of a solar panel gives you an idea of its power output. Higher wattage panels can produce more electricity in the same amount of time compared to lower wattage panels, assuming they are exposed to the same sunlight conditions. This means that with higher wattage panels, you might need fewer panels to meet the electricity demands of your home, which can save space and potentially reduce installation costs.

When selecting solar panels, considering the panel wattage is crucial because it affects the overall energy production capacity of your solar PV system. It helps you understand how many panels you'll need to meet your energy goals and can impact your system's design and cost.

Most panels used in residential solar systems today range from 415W to 450W.

Solar Panel Efficiently

Panel efficiency refers to how well a solar panel can convert sunlight into electricity. The percentage expresses the proportion of sunlight that can be turned into usable power. For instance, if a solar panel has an efficiency of 20%, it means that 20% of the sunlight hitting the panel is converted into electrical energy.

The efficiency of a solar panel depends on the design or the panel and the materials used in its construction.

Higher efficiency panels have several advantages. They can generate more electricity from the same amount of sunlight compared to lower efficiency panels. This is particularly beneficial in areas with limited roof space, as fewer high-efficiency panels are needed to produce the same amount of power as more low-efficiency panels. This can lead to savings on installation and equipment costs over time.

However, high-efficiency panels typically come at a higher upfront cost. When selecting home solar panels, it's important to balance the efficiency with the cost and the available space to get the best return on investment.

Are high wattage panels more efficient?

High wattage panels are not necessarily more efficient. The higher wattage indicates they can produce more electricity under standard test conditions. The efficiency of a solar panel is a separate metric that indicates how effectively it converts sunlight into electrical energy, expressed as a percentage.

A high-wattage panel can result from either a larger physical size, allowing it to capture more sunlight, or higher efficiency, enabling it to convert more of the sunlight it captures into electricity. Here's how these factors interplay:

1. High Efficiency: A smaller panel with high efficiency can have the same wattage as a larger panel with lower efficiency because it converts a greater percentage of sunlight into electrical energy. In this case, the high wattage is because of the panel's ability to efficiently use the sunlight it receives.

2. Larger Size: A larger panel may produce more power (higher wattage) simply because it has a larger surface area to capture sunlight, even if its efficiency isn't particularly high. This doesn't necessarily mean the panel is more efficient; it's just bigger.

Therefore, when evaluating solar panels, it's important to consider both wattage and efficiency. High wattage panels that are also highly efficient are ideal because they produce more electricity in a given area, which is particularly valuable in limited space scenarios such as homes in inner Melbourne. However, a panel's higher wattage alone doesn't guarantee it's more efficient—it could also be a result of its larger size.

Solar Buying Tip #1
Solar sales companies emphasise solar panel wattage when marketing residential solar panels to potential customers. They suggest that a larger panel with higher wattage signifies a 'better' panel. However, in reality, these may be low-quality, inexpensive panels that are simply larger. Moreover, some companies might even propose extremely large commercial solar panels not designed for home solar systems, posing installation risks.

Solar Panel Warranties

Solar panel warranties are crucial for protecting your investment in a solar panel system. These warranties cover various aspects of solar panel performance and durability, ensuring that your panels function effectively over a specified period. There are two main types of warranties for solar panels:

1. Product (or Materials) Warranty: This warranty covers the panel itself against manufacturing defects, premature wear and tear, or failures due to environmental factors. It guarantees that the panels will be free from defects in materials and workmanship for a certain period, typically ranging from 15 to 40 years. If a panel fails due to a manufacturing defect within this period, the manufacturer will repair, replace, or refund the defective panel.

2. Performance Warranty: This warranty ensures that solar panels will produce a certain percentage of their rated power output over time. Solar panels naturally degrade and produce less electricity as they age.

A performance warranty guarantees that the panels will not lose more than a certain percentage of their efficiency each year and will retain a specified percentage of their original performance after a certain number of years, usually around 80-90% after 25 years. For instance, a performance warranty might state that after 25 years, the panels will still produce at least 80% of their original output.

Some manufacturers might also offer additional warranties, such as a labor warranty, which covers the cost of labor for replacing defective panels.

When choosing solar panels, it's essential to carefully consider the terms and length of both the product and performance warranties. A longer warranty period and comprehensive coverage reflect the manufacturer's confidence in their product's durability and performance, offering you peace of mind and protection against potential future issues.

Solar Buying Tip #2:
Many companies highlight the 25-year performance warranty of their panels but may not fully explain what this means. Essentially, they're guaranteeing the panels will retain a certain percentage of their efficiency after 25 years, but that percentage could vary significantly—from as low as 10% to as high as 90%. It's crucial to read the fine print to understand what you're getting.

For those seeking high-quality solar panels, SunPower Maxeon Panels stand out with a 40-year product warranty and a 40-year performance warranty guaranteeing 90% efficiency, offering superior long-term value and reliability.

Solar Buying Tip #3
The value of a warranty heavily depends on the stability and reputation of the company offering it. If your solar installer goes out of business—a common occurrence with hundreds folding each year - or if the panel manufacturer exits the Australian market, your warranty could become worthless.

To minimise this risk, opt for a well-established, reputable residential solar installer and choose panels from a trusted solar brand.

Learn more about PV panels

How do Solar Panels work

Solar panels convert sunlight into electricity through the photovoltaic (PV) effect. Sunlight hits the panels, energising electrons in the silicon cells, creating an electrical current. This current is then converted from direct to alternating current by an inverter, making it usable for homes and businesses.

The different Types of Solar Panel

We can categorise solar panels based on the technology or materials used in their design and manufacturing.

Silicon Crystal Types:

Monocrystalline panels, made from single, pure silicon crystals, are known for their high efficiency and distinctive black appearance.

Poly silicon solar panels, made from polycrystalline silicon, are recognised for their blue hue and affordability, offering slightly lower efficiency compared to monocrystalline panels.

Silicon Doping Types:

N-type (negative) silicon is a high-purity form of silicon doped with elements that provide extra electrons, enhancing its electrical conductivity and efficiency in solar panels.

P-type (positive) silicon is doped with elements that create "holes" or positive charge carriers, making it the most commonly used base material for solar cells due to its good electrical conductivity and lower cost.

Construction Types:

Standard (single-glass) solar panels feature a single glass layer on the front and a plastic backing sheet that encases the solar cells.

Double glass solar panels feature two layers of glass to encase the solar cells, enhancing their durability and lifespan compared to traditional single-glass panels.

Bi-facial solar panels are designed to capture sunlight from both sides, increasing energy production by utilising reflected light in addition to direct sunlight.

How much do solar panels cost

Prices of Solar panel Australia are among the lowest globally, thanks to technological advancements, a competitive market, and numerous solar rebates and incentives. Over the past decade, the installed cost has significantly dropped, now averaging around $1 per watt.

However, this average can be misleading due to variations in product and installation quality, the complexity of the installation, as well as the subsidies on offer. The most accurate way to determine the cost of installing a solar PV system in your home is to obtain a solar quote from a reputable solar installer such as Essential Solar.