Learn about the solar technologies that can harness the sun's energy to provide hot water and space heating for buildings.

Solar panels explained

The term ‘solar panel’ is often used interchangeably to describe the panels that generate electricity and those that generate hot water.

  • Solar panels that produce hot water are known as solar thermal collectors or solar hot water collectors.
  • Solar panels that produce electricity are known as solar photovoltaic (PV) modules. These panels generate DC electricity when exposed to light.

Solar thermal collectors

There are a range of technologies which transfer the energy from the sun into space heat or hot water. In Ireland, the most common technologies are solar thermal collectors, or solar hot water collectors. These devices capture solar energy and transfer it to heat water.

The amount of water supplied by solar thermal collectors depends on the system size and building hot water demand. Typical well-installed systems provide approximately 60% of hot water demand over 12 months. There are two general types of solar thermal collectors.

Flat Plate Collectors

These collectors have a heavy, rigid, and robust, box-like structure. This means you can position them both in-roof and on-roof. They are typically lower in capital cost than evacuated tube collectors, but the hot water produced will generally be at a lower temperature.

Evacuated Tube Collectors

Evacuated tube collectors have a lightweight structure. This usually consists of individual tubes mounted on a frame. Their structure means you can only position them on-roof.

Compared to flat plate collectors they:

  • Will provide approximately 20% more hot water per m2 of aperture (surface) area
  • Demonstrate higher efficiencies in low radiation, so typically perform better in cloudy conditions
  • Typically have a higher capital cost

Investing in a Solar Thermal System

Are you a homeowner, community or business interested in a solar thermal grant and system? Then there are several important elements to consider.

Find the right installer

Finding a competent installer is important. There are currently no formal qualifications mandated which installers must hold to install a solar thermal collector system. However in order to avail of the solar thermal grant it must be installed by a contractor that is registered with SEAI.

Our advice would be to get a range of quotes from installers or contractors listed on the Renewable Installers Register.

Choose the right equipment

  • Research the type of system you want and then find an appropriate installer.
  • You can also speak to a range of installers about the products they offer, or speak to a BER assessor.
  • Consult the Triple E Register which identifies solar collector products which meet a minimum set of performance criteria, including energy efficiency.

Check planning permission

Solar thermal systems installed in a domestic setting under 12 sq. m (and representing less than 50% of the total roof area) are exempt from planning. The same exemption applies to solar thermal systems in a business or industrial setting that are under 50 sq. m.

For more information download the guide below: