Ultimate Guide to Installing Solar Panels

The size of your solar PV system should be driven by your energy usage now and how this may change in the future. For businesses, you may want to anticipate and accommodate future growth, or you may choose to build your solar energy generation in line with your growth and have subsequent systems rather than one big investment. When considering a domestic installation, you might want to factor in additional loads such as a heat pump or an Electric Vehicle charge point.

The number of panels will be determined by the amount of energy your system needs to generate and the amount of suitable space you have available to install them. Your installer should request copies of your energy bills so they can see your kWh usage throughout the year and the energy tariff that you are on. A survey of the property should also be carried out to identify where panels and inverters can be located and how easy it will be to access your roof and install cables.

The orientation and pitch of your roof will impact the efficiency of your system, but this should be taken into account as part of the design and your proposal should be tailored to your property.

The output is different for individual makes and models of panel, but once your installer has determined what you need to generate and where panels can be installed they will be able to say how many, and which panels they recommend. There are several types of solar PV panels to choose from, and your installer should recommend the best option for you taking into account your budget, output requirement and space available.

In addition to the number and type of panel being used, your proposal should provide details of the inverter required for your installation, any other materials and components, scaffold and access and a detailed breakdown of when you can expect to see a return on your investment. It’s also best practice to include an overview of how much energy your system will generate over the course of 12 months, the CO2 saving and details of how you will be able to monitor your generation.

Unless you are working with an installer who you have worked with before or has been highly recommended, we advise that you seek comparable quotes to understand whether you are being recommended the best solution. A good installer should also look at whether or not battery storage could be incorporated into your system to deliver additional savings.

Once you have chosen your installer and agreed on your proposal, work can begin on your installation. Depending on the process that your installer follows, and whether they offer an inhouse planning and permissions service, you can expect all or some of the following steps to take place.

As soon as you decide to go ahead, your installer should contact your DNO (District Network Operator) to confirm their agreement for you to connect your system to the Grid. Depending on your local DNO this could take a few weeks, so it’s important that this is done quickly to start the process. If you are connecting a large installation your installer will advise you of any steps that you need to take with regards to your installation to ensure that you receive DNO permission.

Although the majority of solar PV installations don’t require planning permission, there are cases where this is needed such as with listed properties, some ground mounted systems or very large commercial installations. If your installer offers planning applications as part of their service they will take care of this process for you, but you may need to action this yourselves if they don’t.

As part of the sales and quoting process your installer may or may not have visited your site. We would expect that a site visit would have been carried out for large installations, but your project may have been quoted for through a tender process or your building may not have been finished when you agreed your solar proposal.

A site visit prior to installation is essential to ensure that your project is properly planned. Engineers and/or surveyors will look at your existing electrical installation, roof type and start to make detailed plans on how they will access your property and undertake the installation. This on-site meeting can be used to discuss ways of working to ensure your day to day operations aren’t affected, where cable runs will go, whether there are existing trenches and ducting that you would like to be used and any other fine detail of the installation. This visit would also be when issues such as the presence of asbestos would be identified or if there was the requirement for further structural assessments or electrical upgrades.

At this early stage there may be a requirement to adjust your proposal and your installer should highlight any concerns they have or additional costs for you to approve before proceeding any further. Following this meeting we recommend that you get assurance that the project will now proceed as quoted to avoid any unexpected costs at a later date.

Whilst you wait to receive your DNO permission and any outstanding planning decision your installer will be planning your install using the information gathered at the site meeting. Materials will be ordered, scaffold plans will be produced and agreed with you and a detailed schedule of work will be issued providing details of installation dates, deliveries, waste collection and all of the other elements involved. Risk assessments and method statements will be produced and shared with you and any other documentation that you require for your site will be produced and approved.

If you’re having a roof mounted system it’s usual for scaffolding to be erected the week before your installation and you may be asked to receive deliveries of materials or plant hire. You should now feel fully prepared for your installation to start and have a clear idea of how long the team will be on site and when you can expect to be producing your own clean, green electricity!

Smaller, domestic and residential solar installations are often completed in a day, with larger installations obviously taking longer. Due to most large, commercial systems being installed on roof tops or unused areas of land, companies can operate business as usual and your install team can work without you even noticing they are there.

Factors which can affect the time taken to complete your installation include weather conditions such as heavy rain and strong winds. If these occur your installation team will have to pause any work taking place on your roof for obvious reasons, but work can continue inside your plant room.

The type of roof you have, and whether your system is ground mounted, will determine the exact installation method; but each install will start with the team carefully laying out your roof or ground mount system. Mounting will then be erected and secured and then your panels will be fitted to the frames or console tubs depending on the chosen method.

Your electrical installation will be completed alongside the panels. An inverter or inverters will be installed in the agreed location, any required metering and isolation will be completed, and all cabling will be run with a watertight entry point leading to any roofs.

The final stage of your installation is commissioning. This is when your system is fully integrated into your electricity supply, switched on, all software is updated and any monitoring equipment is put in place. Depending on your existing electrical set up your install team may need to switch off the power; an appropriate time should be agreed with you well in advance and often can be done out of hours for commercial operations.

Before the team leave ensure that your installer has scheduled a full walk round and handover of your system. A member of the install team needs to show you how to isolate your system should you need to, how to carry out visual checks and where to find meter readings etc. Your system should also be clearly labelled

Some solar PV installers will offer to support you in setting up an export agreement with your energy provider. If you have a domestic system you will be eligible for the SEG (Smart Export Guarantee). If you have a larger, commercial system a Power Purchase Agreement (PPA) may be your best route.

If you will be using the majority of the power that you are generating, your export contract will be less important, but if you have a large surplus you will want to secure the best option available to improve your return on investment. You should check that export calculations form part of your initial proposal, and you should discuss with your installer whether they will support you in securing your agreement.

Solar batteries make it possible to store any excess energy that you produce for use at night or at times when your electricity consumption is higher than the energy being generated by your panels. Battery storage may enable you to avoid purchasing any electricity from the grid during times when you are paying peak tariffs, and in some circumstances households and businesses use night-time rates to charge their batteries to make their battery and solar installation run in the most cost-effective way.

You should be aware that not all solar batteries provide a back-up during power cuts. If this is functionality that you require you should make sure that your chosen product will do this; and get your installer to confirm how much power it can provide and how many of your circuits will be supported.

Adding a battery to your installation will significantly increase the cost of your system, and you should ensure that your energy rates and usage make it a sensible addition. Some combined systems use a hybrid inverter for both the solar and the battery. Some systems have a separate solar inverter and an additional inverter within the battery itself. If you’re not sure about investing in them both straight away, discuss with your installer the options for installing solar first and then adding a battery at a later stage and how that would impact the overall cost.

Solar PV systems are low maintenance, and once installed their running costs are minimal and long warranty periods make them a very safe investment. However, we do recommend that you have your system checked once a year, and that this includes a panel inspection from the air to identify if any build up of dirt or debris is reducing the overall generation and efficiency of your system.

If your panels are dirty they should be cleaned by a professional window and panel cleaning company. It’s unlikely that a panel clean will be needed every year as the angle of installation and local rainfall is usually enough to keep them free of dust and dirt, but it may be required from time to time.

Not all installers will recommend or provide service and maintenance as part of their offer. That doesn’t mean that you shouldn’t choose them, but be aware that after their initial installation warranty runs out that you might need to find someone else to look after you and your system going forwards.