A solar water heater uses sunlight to heat water during the day and stores it in an insulated tank, so hot water is ready whenever you need it. It is among the most cost-effective uses of solar energy.
How it works
Collectors on the roof absorb sunlight and heat the water. The hot water rises into an insulated storage tank, from where it flows to your taps.
Main types
- Evacuated tube collectors (ETC): rows of glass tubes, as seen in many Indian homes. They perform well across conditions and are widely used.
- Flat plate collectors (FPC): a flat panel with pipes inside, often used for larger systems.
Choosing the capacity
Capacity is measured in litres per day (LPD). It depends on how many people use hot water and how much they use. Hostels, hotels and hospitals use much more than a family home, so sizing is done during the site visit. Oversizing wastes money; undersizing means running short of hot water.
Cloudy days
On cloudy or rainy days, water may not get as hot. Many installations include an electric backup element in the tank for those days.
Looking after it
- Clean the tubes or collectors periodically.
- In areas with hard water, the system may need descaling from time to time.
- Have the system checked now and then by a technician.
Where we have installed them
We have installed solar water heaters in Nagaon town and Dima Hasao. See our projects and the Solar Water Heater page, or request a call back.
Want this worked out for your roof?
Book a free site survey. We will size the system and handle the subsidy paperwork.