The solar solution

Solar thermal installation

In Sustainability, Environment

Look around any residential area and you’ll see solar panels adorning the modern day skyline. Where once they were a novelty, they are frequently becoming more of a norm, with the solar panels once considered an eyesore still looking like an attractive investment option, despite changes to the Government Feed-in Tariff Scheme.

So, if the recent hot weather has got you thinking about going solar, what are the main things you should consider? In the UK domestic setting, there are two main types of systems in use, namely photovoltaic solar power or solar water heating.


Solar power (PV)

Solar power (electricity) is the conversion of free and sustainable sunlight into electricity by using photovoltaics (PV). PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The panels send this direct current (DC) to an inverter, which turns it into alternating current (AC) – this electricity can be used in any application in your home.

The stronger the sunshine, the more electricity is produced. Groups of cells are grouped together in panels or modules that can be mounted on your roof.


Solar power benefits:

Solar power can cut your electricity bills and cut your carbon footprint, by up to 1.6 tonnes of carbon per year. Although the panels still work even on cloudy days, it’s worth remembering that greater savings will be made during the daytime and during summer than the winter, due to daylight quality and quantity.

In addition if you could be paid for surplus electricity, if you sell it back to the grid, via a Feed-in Tariff scheme or Smart Export Guarantee (SEG). If you decide to keep the surplus energy to power an emersion heater in a hot water tank etc. a PV diverter can be used. You can also combine PV with other renewable technologies such as heat pumps, solar thermal panels (see below) and wind turbines.


Solar power considerations:

You’ll need a decent amount of space on your roof to install this system, which should ideally face south, in an unshaded location and a pitch angle of 30-40 degrees. The Energy Savings Trust advises the rule of thumb to be 10m2 - 20m2 to generate between 20-40% of a typical household’s electricity needs. Additionally it’s good to keep in mind that the greatest benefits will come to those who use electricity during the day.


Solar water heating

This system again uses free heat from the sun, but this time to warm domestic hot water. Solar water heating systems use solar panels, called collectors, fitted to your roof. There are two main types of panels in use in the UK market:

  1. Evacuated tubes - a bank of glass tubes mounted on the roof tiles.
  2. Flat plate collectors, which can be fixed on the roof tiles or integrated into the roof.

In both cases heat from the sun is used to heat up water, which is stored in a hot water cylinder. A boiler or immersion heater can be used as a back-up to heat the water further to reach the temperature you want.


Solar water heating benefits:

Solar water heating will provide hot water throughout the year, although as in PV systems, the system will generate less heat during the winter, so use of a boiler or immersion heater is a must. Additionally, their use will cut your bills and cut your carbon footprint. Again, solar water heating can be used with other renewable technologies such as PV, heat pumps and wind turbines. Unlike PV panels, solar water heating panels offer more flexibility in siting and size.


Solar water heating considerations:

You’ll need approximately 5m2 of roof space that faces East to West through South, and receives direct sunlight for the main part of the day.

It’s likely you’ll also need a larger hot water cylinder or a dedicated solar cylinder with a solar heating coil. Importantly, you’ll need to check to see if your boiler is compatible with solar water heating. You won’t be able to sell back any additional heat generated to the grid – all hot water is for your use only.

It is true the initial costs for both systems may seem heavy and take years to fully pay back their installation price, but if your property offers the ideal setting for solar and you are determined to stay in your home long enough for the system to pay for itself, solar technology can be an extremely good investment.

Both systems can offer genuine ‘green’ solutions for helping you cut your energy bills and your carbon footprint. However, you will need to talk to your heating engineer to see what system is right for you. As always, use an experienced professional via our Find a plumber online tool.

The CIPHE would like to thank the Energy Saving Trust for the information included in this blog. Consumers can find out more on solar from the Energy Saving Trust website:

Solar power (PV)

Solar water heating