Solar Thermal

What is Solar Thermal?

Solar Thermal is a great way of reducing your homes energy consumption while saving money on your energy bills. Heating your water with solar thermal will reduce your homes energy consumption, which will make your home more energy efficient and reduce greenhouse gas emissions. Solar Thermal is the generation of heat using energy from the sun.


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How does it work?

Similar to Solar PV, Solar thermal systems harness energy from the sun. Solar Thermal panels or solar collectors are devices that are mounted on to your roof to absorb the sun’s heat. There are two main types of solar collector arrays:

1. Flat Plate (panel)

  • can be mounted both “on-roof” or “in-roof”
  • heavy, rigid, robust box-like structure

2. Evacuated tube

  • can only be mounted “on-roof”
  • lightweight structure, individual tubes on frame

Solar collectors will use the sun’s energy to heat a transfer fluid within the collectors which is a mixture of water and glycol. The heated water from the collectors is then pumped to a heat exchanger within the water cylinder. The heat from the exchanger will then heat the water inside the cylinder. Once the heat has been released, the water will flow back to the collectors for reheating. This hot water can then be transferred into the home heating system as hot water or for space heating.

It is important to note that Solar Thermal systems are designed to meet 50-60% of your overall hot water requirement over the year – saving you money on bills associated with water heating within your home.

What do I need to consider before installing Solar Thermal?

SEAI advise that before considering investment in solar technologies, it is important to assess the energy performance of the whole home, ensuring your home has a good energy performance rating (BER), upgrading heating systems and then consider Solar PV or Solar Thermal technologies.


The total collector area must not exceed 12m² or 50% of the homes total roof area, otherwise planning permission will be required. Planning should be discussed with your contractor.

Costs and financial support

You should consider the indicative costs for a solar thermal installation before considering installation on your home. The cost of any system will be unique to the hot water demand of your property and can be discussed with an installer. The cost of purchasing and installing a solar water heating system on a home ranges between €800 – €1,300 per square metre. This cost can vary depending on the hardware used, the size of the system, accessibility and the installer used. It is also important to check what financial support is available to you to assist you financially with the installation of a solar water heating system such as the SEAI Home Energy Grants Programme.

What are the benefits of Solar Thermal?

Using Solar Thermal is an excellent way to reduce your bills associated with water heating. It will also make your home more energy efficient and sustainable through reduced greenhouse gas emissions.

Can I get a grant for Solar Thermal?

The SEAI Home Energy Grants Programme offers a Solar Water Heating grant to support homeowners making their homes more energy efficient. Support is available to all homeowners and landlords, whose homes were built and occupied before 2011.

The solar water heating grant has specific requirements in order for the grant to be approved. This includes energy measures having been applied to your full home, meaning the upgrades are completed based on the average number of occupants that could live in a home of your size, rather than the actual occupant numbers. It is important that a compliance check is completed by your contractor before work commences to ensure you remain eligible for the grant. For further details including the amount of grant support you may be eligible for click here

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