What Are the Most Efficient Solar Panels in 2018?

The most efficient solar panel in the world is able to convert sunlight into electricity at an efficiency of 44.5%. However, the most efficient solar panels for residential properties are about 21% efficient. Brands such as LG and Panasonic make some of the most efficient solar panels on the market today. High efficiency solar panels are more expensive, but allow you to generate more electricity.

What's in This Guide to the Most Efficient Solar Panels?

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Most Efficient Solar Panels

The majority of residential solar panels are between 15% and 18% efficient, but the most efficient solar panels have an efficiency of over 21%. Although this might seem quite low, modern solar panels are able to produce enough electricity to cover most (or all) of a household’s energy usage at this current efficiency. As solar technology advances, it’s likely that solar panels will become even more efficient in the future.

Solar Panel Company
Least Efficient
Most Efficient
Canadian Solar
JA Solar
Suntech Power
Yingli Solar

Solar companies often produce several different solar panel models which have a range of efficiencies. The table shows you the most efficient solar panels made by some of the most popular solar companies. We’ve also included the least efficient solar panels for each company as a comparison. As you’ll see, companies like LG and Panasonic manufacture some of the most efficient solar panels on the market.

To find out more about the leading solar companies and their range of solar panels, visit our guide to the best solar panels.

Good to know: the type of solar panel you install can have an effect on its efficiency. The 2 most common types of solar panel on the market are monocrystalline panels and polycrystalline panels. Monocrystalline panels are often the most efficient between 15% and 19%, while polycrystalline solar panels are typically less efficient, between 11% and 15%.

most efficient solar panels

Our Top Tip When Comparing Solar Panel Efficiency

The efficiency rating of a solar panel is usually determined once it’s been through a lab-based assessment. It’s worth noting that these tests can sometimes be misleading as the panels are assessed under optimum, controlled lab conditions, meaning you may not experience the same level of efficiency.

To provide a better indication of the efficiency of a solar panel out of test conditions, some companies also provide an efficiency rating called the PTC (Performance Test Conditions) rating. This is a more accurate measure of the efficiency you can expect to achieve once a solar panel is installed on your roof.

Better still is the 'system PTC rating', which takes into account the efficiency of a solar panel as well as that of the inverter (the device which converts the electrical power generated by a solar panel into electricity that can be used to power your home). Even if your solar panel has a high efficiency, having an inverter with a low efficiency will reduce the overall efficiency of your solar system (and therefore reduce how much electricity you can generate).

How much could you save with Solar Panels? What's your average monthly electricity bill?

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Should You Get High Efficiency Solar Panels?

It really depends on your reason for getting solar panels. If you want to maximise the amount of electricity you generate, we’d recommend installing panels with an efficiency of 19% or more. High efficiency solar panels will enable you to a) earn more money from the Feed-in Tariff (a Government-funded scheme that rewards homeowners for generating electricity from renewable technology), and b) save more money on your energy bills, as you’ll have to buy less electricity from your energy provider.

High efficiency solar panels do cost more money, however, so if you want to maximise your return on investment from the Feed-in Tariff, it’s better to buy lower efficiency (and less expensive) solar panels. This is because it will take less time to recoup the money you spent on them from Feed-in Tariff payments, meaning you’ll earn a higher profit in the long term.

The issue with roof space: if your property only has a small amount of roof space, we’d recommend installing high efficiency solar panels. Although this will be more expensive, a smaller number of more efficient solar panels will produce the same amount of electricity as a larger number of less efficient solar panels - therefore, your roof size won’t hinder how much power you can produce.

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5 Factors that Affect Solar Panel Efficiency

Your solar panels won’t always work at their maximum efficiency and this is because there are factors that can affect how well they convert sunlight into electricity for your home.

1. The direction and angle of your roof: to work at their maximum efficiency, solar panels should be installed on a south-facing roof (although an east or west-facing roof is still sufficient), at an angle between 10 and 60 degrees.

2. The amount of shade on your roof: you should avoid installing your solar panels in shade, even if it’s only a small amount. If a solar panel is not in direct sunlight, it’ll work at a much lower efficiency than it’s capable of.

3. The temperature: solar panels become less efficient at temperatures over 25°C, although this won’t be too much of an issue in the British climate! Make sure your solar panels are installed a few inches above your roof to allow plenty of air circulation, however, so they can cool down on the odd scorcher.

4. The time of year: solar panels work all year round, but they’re most efficient in the summer months (June, July, August) when there’s more sunshine hours.

5. The amount of debris on your solar panels: solar panels lose efficiency when they’re covered with dirt or bird mess. Although we get plenty of rain, don’t always rely on it to wash debris away; clean your solar panels regularly with warm water and a gentle soap to keep them running at their maximum efficiency.

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What Is Solar Panel Efficiency?

Solar panel efficiency is all about how well a solar panel can convert sunlight into electricity. So the more efficient your solar panels (and the more sunlight they get), the more power they’ll be able to produce.

The efficiency of a solar panel is determined by the amount of sunlight entering its cells divided by the amount of electrical power it can generate, represented as a percentage. So if 2,000 watts of sunlight were to hit a solar panel and from this it produced 200 watts of electricity, the solar panel would have a 10% efficiency (as 2,000 / 200 = 10).

It’s worth comparing the efficiency of different solar panels to understand how it impacts the amount of power they’re able to produce. For instance, if you were to install a solar panel with 20% efficiency next to a solar panel with 15% efficiency on your roof, the 20% efficient solar panel would produce up to 30% more electricity under the same conditions as the 15% efficient panel.

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