Best Solar Panels 2021

Solar panels are a win-win technology. Not only do they bring down our energy bills, but they also help us save the planet at the same time. So, with solar panels on our roofs we can feel like we have the financial savvy of Warren Buffet and the environmental smarts of Elon Musk. What’s not to like?

Actually, there is one thing that we might not like. With so many different brands and models of solar panel available, not to mention solar panels being a new technology that most of us know little about, it can be difficult to figure out which are the best for us. Luckily, we’re here to help.

Before we start looking at the actual manufacturers, there are some technical matters that we should explain first. Please bear with us, as there are quite a few points to clear up.

Solar Photovoltaic Panels versus Solar Thermal Collectors

Solar photovoltaic panels are what most people think of when they think of solar panels. These produce electricity that you can use in your home. Solar thermal collectors, on the other hand, heat water for your central heating and hot taps.

Although, a decent solar thermal system can heat 40% of domestic hot water, according to UK government figures, we are going to look at solar photovoltaic (PV) panels here. Incidentally, photovoltaic means the generation of voltage and electric current through exposure to light (‘photo’ is the Greek word for light). So, solar panels and PV panels are the same thing.

Read more: How Much Do Solar Panels Cost?

What to look for when buying a solar panel

Solar Cell technology

There are three main types of solar cell technology: monocrystalline, polycrystalline, and thin film amorphous solar cells. Each has different advantages:

Monocrystalline silicon (sometimes called single-crystal silicon) is the stuff that gives Silicone Valley its name. It makes PV cells that are the most efficient and the most expensive. Its name comes from the fact that it is composed of a continuous crystal lattice, which gives it a single dark colour.

Polycrystalline silicon (also known as multicrystalline silicon or polysilicon) makes    PV cells that are cheaper but less efficient than monocrystalline cells. As it is made up of lots of small crystals, known as crystallites, polycrystalline silicon has a bluer, ‘metal flake’ look.

Thin film amorphous silicon makes solar panels that are the cheapest and least efficient. However, they are the most flexible and thin sheets of PV cells can be wrapped around curved surfaces.


Efficiency is one of the most important qualities to consider when deciding what solar panels to buy. This refers to the amount of electricity that can be produced by the photovoltaic cells. Most solar panels on the market can convert 15% to 22% of solar energy into electricity.

You will tend to pay more for more efficient solar panels. However, efficiency is not always vital. Efficiency is most important for homes with smaller roofs. So, if you live in a town house with a narrow roof then you might need to squeeze every last volt of energy out of that space. If you have larger roof you might be to fit more, but less efficient and thus cheaper, panels.

Power output

The average UK home uses 3,200 to 4,100 kWh (kilowatt hours) of electricity each year. This is why a 4kW solar panel system is the most popular size as it produces 3,400kWh of electricity per year, so it should produce 83% to 106% of your yearly electricity needs, depending on your electricity usage.


Solar panels last a long time, indeed most come with a 25-year warranty. However, they do perform less well over time (what doesn’t?). This process is known in the business as degradation and usually occurs at a rate of 0.8% a year, but in some models can be as low as .25% (for instance some from SunPower). It is another factor to bear in mind when choosing your panels.

How much money you should save on your electricity bill

The average UK electricity bill in 2020 was £707pa. If we look at the savings that solar panels should provide (saving between 83% and 106% of your energy bills), you should save between £586 a year and £749.

Of course, you have to balance the savings you will make on your bills with the initial output for installing the solar PV system. The average solar PV array costs £6,000. This includes installation and fittings as well as the actual panels.

You will earn money back in two ways: firstly on the savings on your actual electricity bills, but also if you generate electricity that you do not use, then you can sell this to your energy company. This is known as a small export guarantee (SEG) tariff.

The amount of energy you generate and money you save (or make) depends on the time of year, the angle of your roof, and crucially how far north you live. This means that the time it takes to recover your costs can take between 15 and 26 years. Sad to say, but houses in the south will earn back their money faster than those in the north.

How much space do you need your solar panels to cover?

A standard 4kW solar panel system generally consists of 16 250 kW panels. Ideally there should be 30cm of space around the edge of the panel module. In total this will add up to 29m² space, which incidentally should weigh around 280kg. If you have the space, a 5kW solar panel system is composed of 20 250kw panels.

Bifacial and monofacial

So what have facials (and beauty salons) got to do with solar panels then? Well, some solar panels have energy-transforming solar cells on both sides – that is, both faces – of the panel. These are called bifacial (bi = two, facial = faced) solar panels. Monofacial panels only have solar cells on the front. Beauty salons and facials have nothing to do with these either of these solar panels, obvs.

Bifacial solar panels are more efficient, as they are collecting more sunlight, however there are a couple of issues with them:

1. They more expensive, this is because they are usually made from monocrystalline silicon and also have solar cells on both sides.

2. Rather than direct sunlight, the reverse cells on bifacial panels use reflected light to generate electricity, so they have to be able capture this. Having a lighter-coloured roof or having a reflective plate fitted under the panels can increase the amount of light reflected. Alternatively they are often fitted on a fixed ground mount, to a solar tracking mount (which follows the sun about the sky like a sunflower), or by using a solar awning on the side of your house.

MCS certification

How do you know if the solar panels you are considering are any good? One of the key signs of quality is if a panel is MCS-certified. This means that the solar panels, the installers or the installation have been certified by the MCS, the UK’s solar panel standards organisation.

MCS stands for the ‘Microgeneration Certification Scheme’ (you will be a microgenerator of electricity after you have solar panels installed). The MCS was set up by the UK government and has been operating since 2008.

Featured Solar Panel Offers

Finally, we have got to the top five solar panels in the UK:

BrandModelMax Power (Watts)Maximum efficiencyWarrantyDimensionsWeight (KG)
LGNeON R Prime370 / 365 / 360 / 35521.4% (370W default)25 years1.700 x 1.016 x 40 mm 
SunpowerMaxeon 3400/ 395/ 39022.6% 22.3% 22.1%25 years1690x 1046 x 40 mm19kg
PanasonicHIT250/ 300/ 340/ 33519.8% 19.5% 20.3% 20.0%25 years1580 x 1798 x 35 mm/ 1053 x 1463 x 35 mm/ 1053 x 1590 x 40 mm/ 1053 x 1590 x 40 mm15kg/ 18kg/ 19kg/ 19kg
Canadian SolarHiKu7 Mono600/ 66521.2% 21.4%12 years on materials & workmanship. 25 years linear power performance2172 x 1303 x 35 mm/ 2384 x 1303 x 35 mm32.5kg/ 35.7kg
SharpNU-JD440/ NU-JD445/ NU-JC370/ NU-JC330440/ 445/ 370/ 33019.9% 20.1% 20% 19.5%15 product guarantee/ 25 years linear power output2,108 x 1,048 x 40 mm/ 2,108 x 1,048 x 40 mm / 1,765 x 1,048 x 35 mm/ 1,684 x 1,002 x 40 mm25.5 kg/ 25.0 kg/  21.0 kg/ 19.5 kg

Who are these manufacturers?

LG are a South Korean multinational who have been producing solar panels for the last 20 years.

SunPower Maxeon are the big US player in the solar panel business, the company was founded in 1985 by Richard Swanson, a professor of electrical engineering at Stanford University. SunPower recently split in two, Maxeon Solar Technologies which operates outside the United States and SunPower which operates within the US.

Both Panasonic and Sharp are Japanese multinationals with good reputations.

The company you may not have heard of is Canadian Solar was founded in Ontario in 2001 and offers panels that are more affordably priced.