8 Questions to ask Your Solar PV Installer

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With more than 4,700 solar companies registered with REAL (Renewable Energy Assurance Limited), a consumer code operator for the renewables industry, if you’re a homeowner keen to install the renewable technology it can be difficult to know who to trust.

Sadly, aggressive sales tactics and bad practice is an unfortunate by product of any sales industry and renewable energy companies are no exception. In light of recent media attention directed at shady ‘Deal of the Day’ sales tricks being employed by a few ‘cowboy’ solar installers, we cannot overstate the importance of doing your homework if you’re looking for an installer to fit solar panels on your home.

So, on that note let’s take a little look at how to go about choosing a solar installer and those pivotal questions you need to ask.

First thing’s first though; you’re going to need to arrange for a few quotes from Microgeneration Certification Scheme (MCS) certified (or equivalent) solar installers. Solar Guide recommends obtaining 4 quotes which we can arrange on your behalf. There’s no-obligation and the quotes are provided free of charge.

1. Is the Solar Installer certified?

At Solar Guide all of our registered solar installers are accredited with MCS or an equivalent scheme. If the company installing the renewable energy technology isn’t certified then you can’t be sure that they are properly qualified to carry out the installation and you won’t be protected under the MCS (or equivalent) scheme should their work prove faulty.

2. Is a Structural Report Included in the Quotation?

A structural report from a qualified ISE structural engineer is extremely important. You should never have solar panels fitted to your property without one. Your potential solar installer needs to determine how strong your roof is before hand and whether it’s going to be able to hold the load. No two roofs are the same, which is why an installer cannot rely on a generic structural report. Your report will be specifically tailored to your roof and will take into account contributing factors such as rafter size, spacing and wind zones which could influence the suitability of your roof for a solar panel installation.

3. Will my Roof Need Strengthening?

Once a structural report has been carried out the solar installer will be equipped with the information needed to determine:

• Whether your roof is suitable and;
• If it will need strengthening.

Around 65% of UK roofs need to be strengthened which is likely to add an extra £200 to £500 to the overall installation and solar panel cost. Without strengthening you could end up with sagging in the beams and cracking in the ceiling.

4. How Will the Panels be Held on the Roof?

Whether you’ve got a tiled roof, a slate roof or even a flat roof, it’s important to know how the installer intends to fix your lovely new solar panels to your roof. A solar PV system can be fitted to practically any type of roof structure but as we’ve previously mentioned it must be physically up to the job, which will be determined by the structural report.

Did you know that solar panels need to be able to breathe? Airflow is essential for efficiency purposes and so for ventilation there must be a gap behind the panels. But of course this leaves the panels exposed and vulnerable to the elements, namely windy weather. If the fixings are inadequate in a worst case scenario – think severe blustery weather – the wind could potentially get behind the gap which could result in the solar panels being torn off the roof.

Quick to install, some installers will utilise what is known as the ‘Click Fit’ system. Popular in the Netherlands and Germany, with this system the panels are essentially hung onto the roof battens – the thin pieces of wood across the rafters – without screws. And given that these roof battens are secured by just one thin nail per rafter, if you employ this mounting system then you’ll be relying on nothing more than a few nails to hold your precious panels in place.

Whilst ‘Click Fit’ is perfectly suitable for our European counterparts – not least because their roofs are built with much stronger battens – in the UK something like the K2 solar mounting system is a safer bet. It employs a bracket and rail system, where the brackets are actually screwed into the rafters, which hold the weight of the solar panels. So in really windy conditions the upward force of the wind on the panels and the roof is actually resisted by the rafters.

5. Will you Need to Carry out Shading Analysis?

Shading should ideally be avoided. However there are ways to minimise the impact and it is important to analyse shading caused by surrounding objects such as neighbouring buildings and trees. If shading could be an issue a good installer should be able to provide you with a computer stimulated shading analysis. Bear in mind that shading will impact on energy yield; you need to know how much electricity the system is going to be able to generate.

6. Who will be Installing the Solar Panels? 

Many solar installers will employ subcontractors to erect and remove scaffolding. This is common practice. But it’s always wise to instruct a company who is going to be carrying out the installation, rather than palming it off to a third party. Either way, make sure you know who is going to be responsible for what work; not least because you need to know who to contact if a problem should arise. Take Solar Guide for example. While our service provides free quotes from up to three MCS certified (or equivalent) solar companies, we are not installers. You can also read our guide to choosing a solar panel installer for more information.

7. What Warranties will be Offered?

Solar panels are designed and manufactured to last for 20 years, but what sort of workmanship warranty will the installer be offering? Most tend to offer 10 years. Similarly how long is the inverter – essentially the heart of the solar PV system – guaranteed for? Again, the majority of inverters will have a 10 year defects guarantee. Inverters don’t last forever; you’re likely to need to replace the inverter at least once. Although you should be able to extend the guarantee at an additional cost.

8. Does the Price Include any Extras?

You need to know exactly what you’re paying for. For example, does the quote include a monitoring solution? Wireless displays are an extremely useful tool to help you make the most of your solar panels, providing instantaneous power output, daily output and historical production information. If you want to make a good return on your investment the system needs to perform to its full capacity over its lifetime. Embracing a monitoring solution will help you evaluate the performance of your panels.

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You Solar Installation Checklist

• Do your home work. Get testimonials from previous customers. Solar Guide customers have the opportunity to rate and review our installers, so that’s a really good place to start. Also ask neighbours, friends or work colleagues for recommendations. And remember Google is your friend; the Internet is a great tool.
• Read the small print and don’t sign anything if you have any doubts.
• Ask questions. If you don’t understand anything, ask.
• Take your time deciding and that means not being sucked into any bullying sales tactics.
• Make sure the installer is MCS certified (or equivalent). If they’re not, find one who is. They should also be accredited under the Renewable Energy Consumer Code (RECC).
• And last but not least get 4 quotes!

The life of a solar farm is well over 25 years and the solar panel cost component is the single most expensive item in a solar installation costing as much as 40% of the total project cost. When investing in a solar farm one needs to select the right solar panels to ensure he gets the expected power and energy production across the life of the project.

Most homeowners are confused in solar panel selection. The most frequently asked questions when deciding to select a solar panel are the following.

1. What is the life of a solar panel? What warranties and guarantees do solar panel manufacturers offer?
2. If there is a problem in solar production over the life of the project, what are the chances the manufacturer will honor the warranty?
3. Which brand of solar panel will produce more power across the life of the project?
4. How much more should I spend on a good quality solar panel?

The short answer to the above question is that solar panels are broadly classified into Tier 1, Tier 2 and Tier 3. Tier 1 solar panels are more reliable and it's advisable to buy them. 

On what basis do you differentiate between the different solar panel tiers?

Fig 1: 6 key components of a solar panel (https://www.cleanenergyreviews.info/blog/solar-panel-components-construction)

Solar panels are made using six main components and assembled in advanced manufacturing facilities with extreme accuracy. These six components are junction box, back sheet, encapsulant EVA (ethylene vinyl acetate) film, solar cells, tempered glass, and aluminum frame. Many well-known solar panel manufacturers are vertically integrated, which means one company supplies and manufactures all the main components used to make a solar panel including the silicon ingots and wafers used to make the solar cells. By doing this the manufacturer can ensure there is no drop in quality in any of the key components used to manufacture a solar panel.

However, many solar panel manufacturers also assemble solar panels using externally sourced parts including solar cells, polymer back sheet and encapsulation EVA film. Unfortunately, it’s very difficult for the manufacturer to control the quality of the products sourced. 

Based on how the key components are sourced and assembled, solar panels are broadly classified into Tier 1, Tier 2, and Tier 3. One of the main differences between the different tiers of solar panels is based on the manufacturing process. The more automation the lower the chances of human error. Also being more vertically integrated reduces any quality related issues in procurement and manufacturing. Tier 1 solar panels are considered premium quality.

Fig 2: Different Tiers of solar panels(https://ensolar.energy/what-are-the-different-tiers-of-solar-panels/)

What do Tier 1 solar panels offer? 

Tier 1 solar panels use the best grade of silicon to produce solar cells. Higher the silicon grade the better the solar panel will perform. In addition, Tier 1 manufacturers control the manufacturing process using advanced robotic processes thereby minimizing or eliminating any human errors in the manufacturing process. They also invest heavily on research and development to stay top of their game. These manufacturers are vertically integrated, that is they tend to manufacture all key components used in a solar panel by themselves. They tend to have an annual production capacity of over 1 GW and have been supplying solar panels for over 5 years.  

Tier 1 manufacturers use the best grade materials to produce a solar panel, hence the solar panels are much more expensive. The solar panels from a Tier 1 manufacturer could be as high as 30% more expensive than others.

Tier 1 manufacturers generally provide a 12 year product warranty and 25 year linear performance warranty on the solar panels. They have a highly regarded reputation within the industry for quality and service and are either publicly listed on the stock exchange or have a strong and stable balance sheet. Tier 1 solar panel examples are Jinko Solar, JA Solar, LONGi, Trina Solar and Canadian Solar. 

What do Tier 2 solar panels offer?

Tier 2 manufacturers use partial robotics in their manufacturing process and rely more on manual work through human production lines. There is a chance of human error in the production line that could lead to lower performance of the solar panel. However, the aim for these manufacturers is to produce good solar panels at a good price. They generally invest very little in research and development and the companies are small to medium in size producing solar panels between 2 and 5 years.

Tier 2 manufacturers also provide product and linear performance warranties on their solar panels but are considered inferior to Tier 1 solar panel warranties. Tier 2 solar panel examples are RenewSys Solar, Luxor Solar and Axitec Solar. 

What do Tier 3 solar panels offer?

Tier 3 manufacturers are typically assemblers rather than pure panel manufacturers. They assemble other manufacturers' cells into a panel. They generally use human production lines for manual soldering of solar cells instead of advanced robotics because of which the quality can vary based on operator skill set. They have zero investments in research and development.

Tier 3 manufacturers also provide product and linear performance warranties on their solar panels but are considered inferior to Tier 2 solar panel warranties. Tier 3 solar panel examples are Tanfon Solar, Dongson Solar and Lovsun Solar. 

Tier 1 Solar PanelsTier 2 Solar PanelsTier 3 Solar Panels Most vertically integratedLess vertically integratedLeast/ not vertically integrated Use best grade of materialsUse moderate grade of materialsUse moderate grade of materials Advanced robotic process in manufacturingPartial robotic process manufacturing processPartial to no robotic process in manufacturing Supplying solar panels over 5 yearsSupplying solar panels between 2 and 5 yearsSupplying solar panels above 1 year Most expensiveModerately expensiveLeast expensive Best qualityModerate qualityLowest quality

Answering the key questions

When buying a solar panel, you are essentially buying two things, a physical product that generates electricity and a guarantee from a manufacturer that specifies the performance of the solar panel year on year. Keeping this in mind, let's answer the below questions. 

What is the life of a solar panel? What warranties and guarantees do solar panel manufacturers offer?

The life of a solar panel is well over 25 years. There are two types of warranties generally offered. One is a product warranty that ranges from 5 years to 12 years and the second is a linear performance warranty that ranges from 15 years to 25 years again based on manufacturer.

Ideally you want to select a supplier who gives you the longest product warranty and longest linear performance warranty.  

If there is a problem in solar production over the life of the project, what are the chances the manufacturer will honor the warranty?

Tier 1 solar panels are built with higher standards (to last longer and produce abundant solar power) and have a highly regarded reputation within the solar industry for quality and service so one can expect Tier 1 manufacturers to honor their product warranty compared to Tier 2 and Tier 3 manufacturers.

Which brand of solar panel will produce more power across the life of the project?

Selecting any manufacturer from Tier 1 list of manufacturers is considered reliable. Some of the top performing solar panels are supplied by Jinko Solar, JA Solar, LONGi, Trina Solar and Canadian Solar. 

How much more should I spend on a good quality solar panel?

One can expect to spend between 10% to 30% more on Tier 1 solar panels. 

Conclusion 

Going with a trusted brand from Tier 1 manufacturers removes most of the risks associated with quality of the product and will the solar panels continue to produce power over its lifetime. 

If you want to learn more, please visit our website Mono Solar Panel manufacturer.