Hot Water from Solar Thermal Collectors
Learn about the solar technologies that can harness the sun’s energy to provide hot water 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 transform the energy from the sun into 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 up to 60% of hot water demand over 12 months. Solar thermal collectors can also meet some portion of space heating demand, although typically this is very small. 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
Do you know that homeowners in Ireland are entitled to a grant towards the cost of a solar thermal system?
A solar thermal system can help you to:
- Reduce your hot water bills
- Increase your home comfort levels
- Support the climate by reducing your own greenhouse gas emissions
Useful information for homeowners on what to expect when investing in solar thermal collectors can be found in our homeowner’s guide to solar thermal:
Download the Homeowners Guide to Solar Thermal for Hot Water