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Blog Post 11 February 2021 Updated 23 February 2024

Could solar water heating work for you?

Solar water heating (also known as solar thermal) is a low carbon, renewable technology that uses energy from the sun to warm domestic hot water. It’s a sustainable alternative to heating systems that rely on fossil fuels, such as oil and gas fired boilers.

Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to heat up water that’s stored in a hot water cylinder. You can use a boiler or immersion heater as a back up to heat the water further to reach the temperature you want.

The system works all year round, even on cloudy days. However, you’ll need to boost the temperature of the water using a boiler or immersion heater during the colder months.

Find out whether a solar water heater could work for you with our quiz.

Why should I consider solar water heating?

There are different reasons for getting solar water heating, including:

  • Reduce your carbon footprint: solar is a renewable energy source, which means less carbon emissions.
  • Cheaper energy bills: using sunlight to heat your water means you can save how much you spend on your hot water.
  • Year-round system: these systems work throughout the year. Just remember that you’ll need a boiler or immersion heat to keep your hot water supply going – especially during the colder months. A solar water heating system should provide you with around 90% of your hot water needs the summer and 25% in winter.

How to make the most of solar water heating

There are a few things you need consider to get the most out of your solar water heating system.

Limit how much you heat your water using electricity from the grid. Instead, make sure your solar supply is being used to provide hot water as much as possible.

For example, you can fit a mixer shower rather than an electric shower. Electric showers use electricity to heat the water, but mixer showers take water from your existing hot and cold water supply. Before you install a mixer shower, check with your plumber that the water pressure is sufficient for your needs.

Solar water heating systems might be useful if you use more of your hot water in the evening. This gives the sun more time to heat up the water during the day.

However, it’s more important to make sure that your back-up heating system is set up to come on at the right time. Before you installed the solar panels, your boiler or immersion heater was probably set to give you a full tank of hot water in the morning. If you leave it like this, your system will always start the day with a hot tank and there’ll be no water for the solar panels to heat during the day.

Your installer should advise you on how to set your hot water controls to get the most out of your new system, whatever time of day you use hot water.

Further reading

Last updated: 23 February 2024