How to compare Solar Installation Quotes

Solar quotes can be difficult to understand. You might have received one or two quotes at this point. What are the key points to look for, for you to be able to compare these quotes? In this blog post, we hope to give you some pointers for things to look for.

Solar company

Make sure the company has a good reputation, has good references, is good in communication with you as a customer, and provides sufficient warranties and guarantees. The company should be able to do a site visit, perhaps after paying a small deposit, in order to customise the quote to your needs. They should be willing to establish a good working relationship with you. They should also be willing to show you some of their previous installations and give you contact details of their previous customers. 

System size

Make sure the company has checked all your requirements and that they have gone through all the issues together with you to determine the correct size of installation for your needs. Some companies also offer to do a an energy analysis and a full PV / solar analysis to determine the number of panels you might need for your home.

The company should also have discussed the possibility of expanding the system at a later stage, e.g. by starting with a backup system first, and then including solar panels later, or by buying one inverter first and adding an additional inverter in parallel later, or adding additional batteries later. Make sure your system allows for that, if that's what you want in the future.

Price

In your quote, all items should be priced separately, including separate items for installation, panel mounting and consumables. Without this detailed breakdown, you’ll have an impossible time trying to compare different quotes. Make sure the quote has VAT as well.

A word of caution here: many companies are hesitant to provide all the exact detail of all the equipment to use for your system. Too many clients will use the quotations to shop for a cheaper price, while the first company has done all the hard work in sizing and providing the details of your system. This is happening and it is important that you as a customer value the amount of work and time a proper quote requires. Stick to the companies that are ready to put in the hard work, this will pay off later when you need their customer service.

image: energysage.com

Make sure you select reputable and high-quality brands that won’t cause any issues later, with good warranties High-quality solar PV equipment that will last you for let’s say 10 years is expensive and going cheap is something that you might regret later, when it will be expensive to replace your system. Check how long the quoted price is valid for. Make sure all transport, VAT and shipping prices are included.

A possible comparison that you could do is “Cost per Watt-peak (Wp)” of your solar panel system. Add the total cost and divide by the total kWp of the quote. This will give you at least an idea on how the quotes compare.

Equipment details

All details of all equipment should be mentioned in the quote; brand, model and sizes, the more detailed, the better. Many quotes don't show these details, and then you don't really know what you are buying.

• Solar PV panels
  • Brand name and model
  • Mono-crystalline or polycrystalline (see this blog post)
  • Watt-peak (Wp) per panel
  • Number of panels
  • Warranty on panels
  • Also see our blog post on what to look for when buying solar panels
• Mounting of the panels
  • Brand name
  • Make sure the correct mounting is used for your roof material
• Inverter / charger
  • Brand name and model
  • Warranty
• Charge controller (preferably MPPT, sometimes integrated in inverter)
  • Brand name and model
  • warranty
• Battery bank
  • Brand name and model
  • Chemistry: Lead Acid (AGM, deep cycle, gel) or Lithium – there is a big price difference: see this blog post on comparing Lithium and Lead-Acid.
• Communication modules
  • Some inverters have communication modules incorporated.
  • Is it Bluetooth or WIFI based, is it available on smart phone or computer?
  • What is the quality of the remote monitoring system on offer?
• Cabling
• Make sure the quote specifies that all cabling, including communication cables are included. 

Ideally, the installer should be able to provide you with all the technical specifications (data sheets) for all the components.

Equipment warranties

Take note of what guarantees the manufacturer offers. If the manufacturer is reputable and the warranty period on the panels is substantial you would naturally expect your solar system to last long for a long time, long enough to pay for itself and make you a profit. Some brands allow you to extend the warranties if you are prepared to pay an extra amount.

Installer warranty

Apart from brand warranties, check which warranties and maintenance services the installers offer and for how long. Your installer should provide a warranty for the system installation which covers the cost of any labour necessary to fix mistakes made by their contractors.

Some installers also offer other services, like monitoring the functioning of your system, regular cleaning of panels and provide an analysis of your system after a certain period.

Certificate of Completion

Make sure your quote includes a Certificate of Completion (CoC),  at the end of the installation, which is required for e.g. insurance – see this blog post.

  
Read more: 
CoC - Certificate of Compliance, why do you need it?
Solar panels, Mono or Poly?
Solar panels - What to Look for when Buying Panels 
Wiring solar panels: Series or parallel?
SunStore Solar System Sizing Calculator
9 Easy Steps towards installing Solar
What DC Wire Sizes to use for your Solar PV System?
What size of inverter do I need?
What are the elements of a Solar PV system?
Iron or Ion ???? Lithium batteries explained...