6 Common Mistakes to Avoid When Installing Solar Panels

Solar panels are very durable, and leading brands are now offering them with product warranties of up to 25 years. They also save you thousands of dollars in power bills during their lifetime, and their upfront cost becomes small in comparison. However, you will only achieve good results with solar panels if they are installed properly.

Here we will discuss some common mistakes when installing solar panels, and how they can affect the performance and service life of your system.

  • Installing solar panels in shaded areas of your roof.
  • Not using the ideal orientation for your solar panels.
  • Wiring panels with different orientations in the same circuit.
  • Installing too many panels.
  • Installing too few of them.
  • Hiring unqualified solar companies for your project.

When working with professionals, there is no need to worry about these issues. However, any solar quote that is offered without a property assessment should raise suspicion: these are generic quotes that don’t account for shading and roof conditions, and they often use low quality materials and unqualified labor.

Mistake #1 – Installing Solar Panels in the Shade

Shading is one of the main enemies of solar panels: if sunlight cannot reach them, their electricity output will be drastically less or even zero. Solar panels in the shade represent a wasted investment since you’re not getting the expected electricity output. For this reason, they should be installed in roof areas with little or no shadows.

Avoiding shadows when installing solar panels may seem like a simple concept, but there is more than meets the eye. Since the sun’s position in the sky is constantly changing, the direction of shadows also changes during the day.

For example, a large tree will cast a shadow towards the west when the sun rises in the east, and vice-versa in the afternoon. You may find parts of your property that get plenty of sunshine during the morning, but in the afternoon, they’re fully covered with shadows.

Shading conditions also change depending on the season. Objects cast shorter shadows during summer when the sun’s position is high in the sky. As winter approaches and the relative position of the sun is lower, objects begin to cast longer shadows. This means a solar panel system can be clear of shadows during summer but covered during winter.

Figuring out which parts of your roof will be free of shadows all year long may sound like a difficult task. However, professional solar installers have design software that can simulate the sun’s position over time, and they can determine which parts of your roof are optimal.

Mistake #2 – Not Using the Ideal Orientation for Solar Panels

Shadows are not the only factor that determines how much sunlight reaches your solar panels. Their orientation is also important, and even the most efficient panels are less productive when poorly positioned.

In northern hemisphere countries like the US, south-facing roof sections tend to get the most sunshine during the year, making them the best choice for a solar panel system.

If you go to Australia, the opposite applies: there is more sunlight coming from the northern half of the sky during the year, and north-facing solar panels are ideal. There are some cases where it makes sense to use other solar panel orientations:

  • Since the sun rises in the east, solar panels facing in that direction are more productive during the morning. The price to pay is a lower productivity in the afternoon, but east-facing panels make sense for buildings that are mostly active during the morning, such as schools.
  • The opposite applies for west-facing panels, which are more productive during the afternoon. There are also electric companies who charge higher tariffs in the afternoon and evening, and west-facing panels will produce energy when the value of each kilowatt-hour is higher.

The ideal orientation for your solar panels will depend on your geographic location, but also how you intend to use their electricity. The same recommendation given to avoid shading issues applies here: by contacting professional installers, you can ensure that your solar panels are placed properly.

Mistake #3 – Wiring Solar Panels with Different Orientations in the Same Circuit

Solar panel systems are often divided into sections with different orientations, with the goal of covering your rooftop space more effectively. This means the same system can have panels facing in different directions, and their productivity can vary during the day.

  • Assume you split 20 panels into two groups of 10, one facing east and one facing west.
  • The east-facing group will be more productive in the morning, while the west-facing group will generate more power in the afternoon.

Ideally, solar panels that are wired together should have similar energy production profiles. Since their orientation determines when they are more productive, solar panels with similar placement should be grouped together.

On the other hand, solar panels with different production profiles will interfere with each other when connected. For example, west-facing solar panels will decrease the output of east-facing panels in the morning, and vice-versa.

Fortunately, modern solar inverters are designed to manage multiple groups of solar panels separately. This means you can have a home solar system that uses roof areas with different orientations, but each group of panels is managed and optimized independently.

Mistake #4 – Installing Too Many Solar Panels

Solar panels are durable and productive, but too many of them can have a negative impact on your return on investment. This might seem counterintuitive, when you consider that solar panels produce electricity with a free resource (sunlight). However, there is an important reason why having too many panels is a bad idea.

Your home consumes a certain amount of electricity each day, which normally comes from the grid. After installing solar panels, they cover this consumption partially or fully. However, when solar generation is higher than your home consumption, the difference is exported to the power grid.  When this happens, you can expect one of the following results:

  • Your electric company will register a credit in your favor, which you can subtract from subsequent power bills.
  • You may get a solar export tariff for surplus production, also called a feed-in tariff, which is normally lower than the electricity price you pay.
  • Some electric companies give no credit for extra solar panels, which means you must either store it in batteries or lose it.

Regardless of what your situation is, these three scenarios have one thing in common: they place a limit on how much solar electricity can be used by your home. A credit that rolls over to the next month is only valuable when you can consume it, but this is not possible when your solar panels are adding even more credits each month.

A small feed-in tariff provides little incentive to generate surplus solar power, since the value of each kWh is decreased after a certain output. Finally, when you get no credit for surplus solar energy, you’re generating power for your electric company free of charge! However, they can still sell it to other customers. 😉

Being able to install solar panels with no limit and then billing your electric company for all their surplus energy would be great. However, there are regulations that prevent you from doing this. Ideally, you should look for a solar generation capacity that will bring your power bills close to zero, without producing an excessive surplus that you can’t consume.

Mistake #5 – Installing Too Few Solar Panels

A solar power system with fewer panels is more affordable, but the financial return is negatively affected when your system is excessively small. This happens because home solar systems have fixed costs that can’t be avoided, regardless of how much you downsize.

For example, there are fixed costs associated with permitting and grid interconnection. There are also some necessary components regardless of the solar system capacity, including the inverter and electrical protections.

When a solar system is too small, the total price is lower but the cost per watt of capacity tends to be higher. You might be paying less upfront, but you also have a longer payback period and a smaller return on investment.

Mistake #6 – Hiring Unqualified Solar Companies

You will come across many websites that offer solar quotes, and they are often very cheap. However, many of these quotes use low-quality solar panels and components, and the companies offering them are simply sales offices who hire unqualified installers for the job. These quotes may seem like a quick and simple option, but they can bring you plenty of trouble.

For example, a low-quality solar system may fail in a matter of months, when you could have purchased higher-end solar panels that last for 25 years or more. Getting a professional installation is also important since many manufacturers will void their warranties if they can find evidence of poor workmanship. Finally, the risk of fire is increased greatly when your solar panels lack adequate wiring and protections.

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