




Solar panels are an ideal method of reducing fuel bills and making a home more energy efficient and environmentally friendly.
Solar panel electricity systems, also known as photovoltaics (PV), capture the energy from the sun using photovoltaic cells. These cells are able to generate electricity on an overcast day, not relying on direct sunlight to function.
The cells convert sunlight into electricity which a household can utilise.
Photovoltaic (PV) describes the process by which a material converts sunlight into electricity. Derived from the words ‘photo’, which is Greek for light, and ‘voltaic’, meaning voltage, photovoltaic basically means electricity from the energy of the sun.
There are several benefits of switching to solar PV:
Most domestic solar PV systems are 4kWp and cost between £5,000 and £8,000. These systems are capable of generating approximately 3,400 to 4,200 kilowatt hours of power a year, depending on whereabouts in the UK you are based and how they have been installed at your property.
The number of panels you will need will depend upon mainly the size of the space where the panels will be situated and how much electricity you currently consume. Generally, for a 4kWp solar PV system you will need space for 12 to 16 panels as different panels have different wattage capabilities.
If you are looking to purchase a 4kWp solar PV system then it could cost you between £5,000 and £8,000. This is a considerable investment and you may need to look at different finance options available to you. Your options could include:
Following the closure of the Feed-in tariff and the export tariff on 31st March 2019, the Government have introduced a proposed replacement in the form of the Smart Export Guarantee (SEG), which, if implemented would see energy providers pay homeowners for energy they generate.
Solar panel efficiency is determined by testing panels at Standard Test Conditions (STC), using a temperature of 25°C and an irradiance of 1,000 W/m2 – the equivalent of a sunny day with incident light hitting a sun-facing surface tilted to 37°. A solar panel efficiency of 15% with a 1m2 surface area would produce 150 Watts under these test conditions.
If you would like an estimation of how you can expect your solar system to perform over the years, your installer will be able to calculate this using the following method:
In the UK, solar panels are most effective when south facing, as this means they will be facing the sun for the majority of the day. Panels facing north will be far less efficient as they will be facing away from the sun.
The optimal angle of tilt to position solar panels isn’t straightforward. In the UK, the sun is higher in the sky in the summer and lower in winter, meaning that if your panels are pointing at the position of the sun at midday in midsummer, they’ll maximise efficiency over summer but lose out in winter.
In the UK panels that are tilted at 15° or more have the benefit of being cleaned by rainfall to ensure optimal performance.
Shade is the nemesis of solar panels, capable of having a really adverse influence on their efficiency. It’s important to assess the area that you have earmarked for your panels in order to establish any nearby buildings or vegetation that could cause an issue. Also, due to changes in the angle of the sun, shadows will be in different positions at different times of the day and year. It would be prudent to gauge this over a six month period.
This simple answer to this is no, as solar panels need sunlight in order to produce energy. However, homes can still be powered at night with the solar energy that has been captured during daylight hours, if the system is linked to a solar storage battery.
A common misconception is that winter weather will mean lower efficiency. The opposite is often true. Though solar panels are designed to withstand average temperatures, they’re more inclined to function better when they’re cooler. This is true with most electronic equipment. And since solar panels need light (not heat) from the sun, bright winter days can be highly productive. However, as the days are shorter in the winter months, production would be less than in the summer.
Significant amounts of dirt and dust can also reduce efficiency. For the most part, solar panels are self-cleaning. A rain shower can clear dirt and dust away, thereby helping your panel regain its efficiency in just a few minutes.
There are three types of system set-ups for solar panels: Grid-tied, Off-grid and Hybrid. The systems typically require different inverters to manage the set-ups.
Grid-tied solar PV systems are linked with the National Grid so unused electricity can be exported from the home into the grid. With the FITs coming to an end on 1st April 2019 the export tariff is being replaced by the Smart Export Guarantee. Consumers who are currently receiving export payments will not be affected.
Off-grid solar system are not attached to the grid and any electricity not used to power appliances can be stored either by heating water in a tank for domestic use or in batteries.
This system is usually used in remote locations to supplement other off-grid energy sources.
A hybrid solar PV system combines grid-tied and off-grid systems. Excess electricity generated can either be exported to the National Grid or stored locally.
As flexible energy develops, hybrid solar systems will enable homeowners to take advantage of emerging smart electricity tariffs. For example, storing renewable solar power in solar storage batteries and selling back to the grid when they will be paid the most for each kWh.
Solar inverters play a vital role in any solar installation. Their main function is to convert the captured energy from DC to required AC, but they are also used for monitoring and enabling installers and homeowners to keep an eye on how the system is performing. Inverters are also able to provide diagnostic information to make it easier to identify and fix any issues. There are several different kinds of solar inverters and your installer will be able to advise you which one would best be suited to your project.
The process of installing solar panels on a roof consists of the following steps:
All HIES Accredited Installers are continually vetted in many areas in order to give consumers trust, confidence and peace of mind.
Find your nearest HIES installerOnce fitted, your installer should leave written details of any maintenance checks that you should carry out from time to time to ensure everything is working properly. This will include details of the main inverter fault signals and key troubleshooting guidance. Ideally, your installer should demonstrate this to you at the point of handover.
Consult with your installer for exact maintenance requirements before you commit to installing a solar PV system.
Solar panels which are mounted at a sloped angle are typically cleaned by rainwater, but certain conditions can require measures to ensure the amount of electricity they generate isn’t reduced, such as dust or bird droppings.
You will need to shut down your system before undertaking any additional cleaning – your manual will instruct you how to do this.
If possible, it’s safest to clean panels from ground level with the recommended materials – these should also be detailed in your manual, or you can ask your installer.
Make sure you are fully protected before, during and after your next renewable project – always use a HIES member.
From IBGs to dispute resolution, there are many ways HIES can protect consumers using an accredited installer.
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