The Best Colour to Absorb Heat in a Solar Water Heater

Fri, 9 Jul 2021

Solar energy is a power generation initiative that the world is increasingly embracing to generate clean energy that is conducive to the environment. It is a solution used to curb the carbon footprint caused by the use of fossil fuels. Solar energy is beneficial in helping homeowners control their energy bills. 

Solar water heaters are devices that use solar energy from the sun to heat water. When using solar energy to power solar water heaters in homes, it’s important to know that certain factors will affect its efficiency. These factors include the time of the day, the latitude of the installation area, and the amount of sunlight reaches the solar panel. The heat absorbed in the solar water heater is also a huge contributing factor to the functioning efficiency of the solar panels. Additionally, the colour of the solar panel determines how much heat gets absorbed.


Solar Installation 

Every solar installation has a vital component known as the solar collector. The solar collector absorbs the solar radiation from the sunlight and traps the heat energy accompanying the light. The trapped heat is then used by the solar water heater to raise water temperature.

The colour of the solar collector affects its overall efficiency. Different objects absorb visual light differently based on their colour. For example, a red apple appears red because it absorbs other light wavelengths in the visual light spectrum, leaving out the red light, which is reflected in our eyes’ retinas. Solar collectors come in a wide array of colours, so it is helpful to know which colours will allow this solar water heater component to function optimally.

Below, we will look at the solar radiation absorption efficiency of different colours and how they would affect the solar water heater performances.


Bright Colours

There is a reason why bright colours are bright. Colours such as yellow or pink are bright because of the high amount of light they reflect. Most of the light wavelengths are reflected into our eyes, making us perceive them the way we do.


Shiny Colours

Shiny bodies tend to reflect a certain amount of light, as well. It depends on how shiny the body is. For example, a shiny deep blue tends to reflect less light and retain more heat than a shiny yellow. This absorption hierarchy can be used in colouring solar collectors.


White absorbs less energy because it is the sum of all visual light on the spectrum. When you see white, what you are seeing is all of the light wavelengths together. White tends to retain little heat, making it an undesirable colour for solar water heaters in general.



Black is the opposite of white in terms of retaining heat energy. It is the best light and heat energy absorber, making it a suitable colour for solar hot water systems. Black absorbs more light energy than white does. The more light absorbed, the more heat absorbed.



The colour of a solar panel collector plays a huge role in determining how it will power a commercial solar water heater or solar water heater system due to the varying light-absorbing capacity of different colours.
Black is the best colour for a solar collector because it absorbs a huge amount of varying light wavelengths through the surface and traps heat energy. For instance, Solar-Mate's chrome is treated in black colour to enhance heat absorption from sunlight in water heating. For more information, feel free to get in touch with our solar specialists. For more information, feel free to get in touch with us