What are the main disadvantages to solar energy?

According to Energy Saving Trust, a typical solar panels system can cost between £3,500 and £7,300, so the initial expense can be seen as a disadvantage. However, with prices still falling and the rising cost of energy in the UK, they make their money back much quicker than they used to – in some cases as little as five to seven years. Solar energy is dependant on the weather conditions, which can be another disadvantage depending on the region you live. If your part of the country sees a lot of sun and clear days, investing in a solar panel system makes a lot of financial (and environmental) sense. But if your area experiences a lot of darker days, you might be better off investing in ground or air source heat pumps to produce electricity.

Do solar panels wear out?

Solar panels usually have a life time of about 30 years. After this, their efficiency begins to drop and they generate less electricity. Most modern panels can still generate around 90% of their output potential after 25-30 years, according to their manufacturers. Generally warranties will guarantee their performance will remain at 80% or more within the warranty period, which can be as long as 25 years. With correct care, you can find that your solar panels last more than 40 years before their performance warrants replacements.

Do solar panels work at night?

Because solar panels need energy from the sun to produce electricity, there will be no output after dark. To use your solar power at night, it’s a good idea to add a storage battery to your system. Any unused solar energy generated during daylight hours will be stored in your battery for use later.

What are the types of solar panels?

There are two main choices when it comes to solar panels. Cheaper options tend to be made from polycrystalline (poly) silicone cells, whereas the best solar panels are typically made using the more efficient and sleeker-looking monocrystalline (mono) silicone cells. The main difference between the types of panels is that poly panels are made by melting together multiple silicone crystals and mono panels are constructed from a single silicone crystal. Poly panels have a blue appearance, whereas mono panels have a sleek black finish.

Do solar panels work on cloudy days?

Even on the cloudier days, solar panels will still produce electricity. Their output won’t be as high as when there’s little cloud cover, but generally, if you can see outside, the light is good enough for solar panels to work well.

Which solar panel is best for home use?

This depends on your budget, roof size, and geographic location. We would recommend the Peimar SM325M as one of the best all-round options, as well as the SunPower Maxeon 3, which has fantastic efficiency, and JA Solar JAM60S20, which has great output at a good price.

How many solar panels are needed to power a typical house?

The energy requirements of a typical household can be fulfilled with a 4 kW system, using 16 300 W-rated solar panels. These will take up around 30m² of roof space. A system that needs to generate more electricity will need more powerful panels or a higher number of panels occupying an increased area of roof space, depending on the desired output. A 6 kW system, for example, could require 24 solar panels, taking up 43m² roof space.

Peimar SM325M solar panels review

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Peimar is a specialist high efficiency photovoltaic module manufacturer based in Italy. It produces advanced, modern-looking solar panels with an attractive design and a long lifespan, backed by solid guarantees.

The Peimar SM325M is a high performance 325W monocrystalline solar panel with an efficiency rating of 19.48%. These panels have a temperature coefficient of -0.37%/°C to deliver a solid performance in different weather conditions.

Panels are 1665mm (w), 1,002mm (h) and 40mm (d) with a weight of 18.6kg, making them suitable for smaller or more complex roofs. The Peimar SM325M comes with a 20-year product warranty and a 30-year power output warranty, with a performance degradation of 3% in the first year. Thereafter, performance will degrade by 0.59% every year from the second year onwards.

While the SM325M is extremely affordable, the durability and performance aren’t as good as some of the competitors, but it’s still a good option for homeowners that want a cheap and energy-efficient solar panel for their homes.

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Technical information

Peimar monocrystalline solar panels are made using a combination of innovative production processes and engineering techniques to deliver maximum output and high performance. Homeowners need fewer panels to generate more energy, which can be useful for smaller roofs. Their long lifespan makes these panels a good choice for homeowners looking to recuperate costs and cut energy expenditure in the long term.

Power: 325 W
Efficiency: 19.48%
Warranty: 30-year power output warranty and 20-year product guarantee
Cost per panel: From £143

The dimensions of the Peimar SM325M. (Image credit: Peimar)

Key features

Highlights: Highly durable monocrystalline panels will last longer and deliver at an optimum level for several years.

Key benefit: These panels are low-cost but deliver high power and efficiency.

Service: Peimar has a base in the UK and can provide expert assistance and technical support whenever required.

Warranty: 30-year linear power warranty and 20-year product guarantee ensure that you will have support well into the future.

Cost: At £143 per panel, this solar panel system is one of the most affordable on the market.

Pros and cons

The Peimar SM325M is a popular solar panel with several benefits.

Modern design: Peimar SM325M solar panels have an attractive modern design, using matching black cells and panels to blend in with a dark roof.
Solid reputation: Peimar specialises in the design, research and manufacturing of solar panels. They hold a 4.56-star rating on Solar Reviews.
Cost: At £143 per panel, Peimar is one of the most affordable solar panel brands on the market.
High wind resistance: With a 5400 Pa for wind loading, Peimar’s performance is nearly double the industry standard 2400 Pa wind rating.
Lengthy guarantee: With a lengthy 30-year linear warranty, Peimar is willing to back the durability of its product well into the future.

There are always disadvantages that have to be taken into account, including:

Performance: With an efficiency of only 19.48%, the Peimar SM325M is not the best performing solar panel on the market.
Output: While 325kW is a fair output, larger homes will benefit from brands offering 400kW outputs, like SunPower or LG.

Degradation: Panels will degrade 3% in the first year and then 0.59% for every year thereafter, which is a much faster rate of degradation than many of its competitors.

How the Peimar SM325M solar panel works

Monocrystalline cells were developed in the early days of solar panel research. When sunlight hits the silicon semiconductor, energy is absorbed from the light, knocking the electrons loose, allowing them to flow freely and thus creating electricity.

Monocrystalline solar panels are cut into thin wafers from a singular continuous crystal grown for this purpose, whereas polycrystalline cells are made by melting silicon material and shaping it inside a mould. Using a single crystal cell makes the monocrystalline solar module more efficient and gives it an even, deep blue colour.

Monocrystalline cells are laminated using tempered glass, joined with adhesive and framed to form an efficient solar panel.

Peimar SM325M add-ons

Peimar offers a range of accessories and add-ons that help homeowners get the most out of their solar panel system at an additional cost. There’s a wide range of inverters available, managed via an online portal or app.

Homeowners may also want to purchase a combination inverter and battery to store surplus energy, which can also be managed via a convenient web or phone app. Most homeowners also purchase optimisers, which are small devices that connect inverters to panels to monitor their performance in real-time.

How does the Peimar SM325M solar panel compare to other solar panels?

Peimar is an affordable, entry-level solar panel that does hold up to some of the other leading brands on the market, especially in terms of its efficiency and temperature coefficients. While the degradation is quite high, so is the warranty, which can be compared favourably with the likes of market leaders like SunPower and Panasonic.

This table is an overview of how Peimar SM325M solar panels compare to others on the market.

Solar panel brand	Efficiency	Solar panel output	Warranty
Peimar SM325M	19.48%	325W	30 years
Panasonic HIT N 245W	19.40%	245W	25 years
JA Solar JAM60S20	19.5% – 21%	390W	12 years

Its closest direct competitor in the UK is likely JA Solar’s JAM60S20 solar panels. Pricing for the JA Solar panel brand is similar to Peimar, but it performs poorly in terms of degradation as well, dropping to 82% power after 25 years. JA Solar only offers a 12-year product warranty, compared to Peimar’s 20- and 30-year guarantee.

If you are looking for a solid product at a low price that can beat the performance of the Peimar SM325M, the Panasonic HIT N 245W is a good choice. At around £250 per panel (excluding installation and labour costs), with a 25-year warranty, Panasonic is still affordable.

The Panasonic HIT N 245W is another good choice if you’re looking for a compact model. This solar panel’s size means it’s easy to adapt to fit smaller roofs or those with a complicated design. Its efficiency is 19.4%, making it comparable to the Peimar solar panel. At around £250 per panel (excluding installation and labour costs), Panasonic is still affordable and offers a 25-year warranty.

Note that Panasonic no longer manufactures solar panels in house but still works with third-party manufacturers. The Panasonic HIT N 245W may still be available to buy from some providers, and the company will honour warranties.

What does the Peimar SM325M cost?

Peimar PM325M solar panels are among the most affordable on the market, although there are some trade-offs in terms of quality. Here’s how it compares to others:

Name	Output	Cost per panel excluding extras and labour
Trina Solar TSM-DE06X	365W	From £208+
Peimar SM325M	325W	From £143+
Panasonic HIT N 245W	245W	From £250+

Maintaining Peimar SM325M solar panels

Peimar solar panels require little to no maintenance from homeowners. In fact, homeowners are discouraged from actively cleaning or tampering with the solar panels once they’ve been installed.

If you do notice any issue with the performance of your solar panels, it’s best to contact Peimar directly to investigate. If you notice a build-up of dust or debris on the solar panel that is not washing off with regular rainfall, you can use a hose while on the ground to gently clean the solar panels.

What the professionals say

“If you like the thought of a European made panel that is high efficiency and appears at least to be of premium quality, then this may be the panel for you. Their factory is relatively small on the worldwide production scale being only 150m. I suppose one could argue Ferrari also doesn’t make bulk products. They just make very good ones, and I don’t think anyone would argue that point.”

Leon, Lumax Solar review

“Peimar is an Italian solar panel manufacturer, producing highly efficient, affordable PV modules through extensive and innovative R&D. They deliver both monocrystalline and polycrystalline technologies for their modules and are capable of residential, commercial, and utility-scale applications alike. Peimar’s high-quality materials are designed to meet the highest standard of performance, flexibility and durability within the solar value supply chain.”

Solaris Review, Solaris-Shop.com

Customer reviews

“Great performing panels for my application. Good long term from the degradation of conversion standpoint, good warranty and good rating from customers who bought them.”

Mark C Solar Reviews, 2019

“I converted my system from BP to Peimar solar panels just three years ago. The panels work as expected, providing the energy promised. My complaint is not so much about the panels but the warranty that Peimar guarantees. After two years, 4 of my six panels showed signs of impending failure. I am off-grid and can not go without power for obvious reasons. I contacted the installer for directions on how to proceed to have the panels replaced. It took the warranty department a long time to even respond after sending in the information needed to begin the replacement process. As for the panels, they work as a solar panel should, but I would strongly advise that no potential solar panel purchaser looks to other sources for a good product and a company that stands behind its warranty. Peimar has failed this consumer, and I suspect that any other purchaser of Peimar products would experience the same lousy customer service as I have. Forget about Peimar; look elsewhere. The failure of this product and the cost to replace it will come out of your pocket. It appears that their warranty changes with every new product introduced, so as they say, “Buyer Be Aware”.”

Kingpenguin, Amazon review

Final recommendation

Peimar panels are affordable and efficient. While they are not the most powerful on the market, there are a lot of advantages to choosing Peimar. They are cheaper than most, perform well, and come with attractive warranties.

The sleek, slim, and all-black design makes them easy to live with in the long term, and while durability isn’t the best on the market, it’s far from the worst. Judging by the number of positive reviews written by customers on various sites, most homeowners are happy with their Peimar panels.

In short, they provide a solid output and performance for space-restricted homes, homes with complex roofing designs, or homes located in areas where they face challenging weather conditions. They are also great for budget-conscious homeowners that want to purchase solar panels for their starter or retirement homes.

Read more about how much you can save with solar panels, or find out about how solar panels are installed. To help you decide if solar panels are right for you, read our are solar panels worth it article

Solar panels FAQs

Our methodology

We know how difficult it can be to find the right solar panel system for your home. To write this review, we first read and analysed hundreds of customer reviews on sites like Trustpilot, Google and Solar Reviews. We also studied reports and reviews by solar panel experts. Then, used a scoring system with a total of 100 points to rate the performance of the Peimar SM325M.

The score was comprised of the following:

The power rating of the solar panel, for a maximum score of 10 points;
The efficiency of the solar panel, for a maximum score of 15 points;
The pricing of the solar panel per panel, for a maximum score of 10 points;
The length of the warranty, for a maximum score of 10 points;
Service and support, for a maximum score of 5 points;
Durability, (for a maximum score of 15 points;
Design, for a maximum score of 5 points;
Performance, for a maximum score of 15 points; and
Online ratings and reviews, for a maximum score of 15 points.

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