Did you know that a regular electric water heaters (geysers) consumes a lot of energy, is rated at 2-3 kilowatts and adds a couple of thousands to yearly electric bills? A simple and very effective way to reduce your electricity costs for heating water is to install a simple solar water heater.
What Is A Solar Water Heater?
A solar water heater is a device that heats water using sunlight and stores it for use 24×7 in an insulated tank. It is a one time investment and doesn’t require any electricity or fuel cost to run.
How Does It Work?
Ever noticed how you sometimes get warm water in the water pipes in the afternoon? This happens usually in older homes that have metal pipes. Solar water heaters use the same principle. Sunlight heats the black painted metal pipes carrying water and the glass surface prevents the heat from escaping (greenhouse effect). The hot water is circulated and stored in an insulating tank (similar to the one on electric geysers) fitted at the top.
Does It Work During The Night?
The water heated in the day stays hot throughout the night in the insulated tank, so that you can use it 24×7.
What About Cloudy Days?
On cloudy days, you can get warm water if there is some light diffusing through the clouds. If not, you can add an optional electric heater in the solar water heater or in your bathroom.
How Much Space Is Required?
Usually you’ll need around four by four feet on your terrace for a domestic solar water heater. The area should get maximum sunlight throughout the day.
Any Special Plumbing Required?
Yes, the hot water outlet will be piped to your bathroom or wherever you want to use. It is usually done by the same people who install it.
I Live In An Apartment. Can I Install A Solar Water Heater?
Unfortunately, not. The amount of sunlight you receive on the most sunny side would still not be sufficient. You can always install it on your building’s roof and hot water can be piped to everyone’s homes if they so desire.
What Can I Use The Water For?
You can use it for every purpose.
How Much Does It Cost?
Solar water heaters are affordable. Prices start at around INR 10,000 for a basic system. A 100 litre capacity solar water heater is ideal for a family of 3 to 4 and costs around INR 15,000-20,000.
What Size Do I Need?
To find the right size, you can add the total requirements from the following and multiply it with the number of persons in your household.
Bath – 10 to 20 liters per person.
Bath in bathtub – 50 to 75 litres per person.
Shaving, hand wash, brushing – 7 to 15 liters per person.
Kitchen washing – 2 to 3 liters per person.
Dishwasher – 40 to 50 litres per wash cycle.
Washing machine – 40 to 50 litres per cycle.
*These are approximate numbers.
How Much Will I Save?
Depending on how much you use, you are looking at saving INR 3000-8000 per year domestically. You can save more if you use hot water to cook or wash clothes. Warm water will require less gas or electricity to heat. You will be helping the environment by reducing tons of CO2 and other pollutants that are produced from producing electricity.
How Popular Are Solar Water Heaters In India?
Solar water heaters are a common sight on homes and buildings in the southern and northern parts of the country. In Karnataka, it is mandatory for most buildings. Maharashtra too is planning to make it mandatory for all new buildings of a particular size.
Our Area Barely Has Winters. We Use Hot Water For Around 15 days In A Year, Is It Worth Investing?
No, in such a case it is better to invest the same money in a small solar photovoltaic panel (one that converts light to electricity). Say, you need hot water for 15 days. That means you need around 30 units of electricity. A 100 watts solar panel would cost the same as a 100 litre solar water heater and would produce the same energy in two months. Your electric geyser won’t directly run from the 100 watts solar panel but you will be offsetting more energy and carbon required to run it in this way.
Are There Different Types Of Solar Water Heaters Available?
Yes, they are mainly of two types – flat plate collector (FPC) and evacuated tube collector (ETC). ETC systems are cheaper and better for colder regions than FPC. For commercial applications, a pump is used to circulate the water.
Can It Be Used In Commercial Applications?
Yes, solar water heaters are very popular for hotels, hospitals, industries and many other places where hot water is constantly used. The savings are more and the payback time is quicker for commercial applications. In fact, the government has made it mandatory for some commercial buildings.
Are They Safe To Use?
They are safer than electric water heaters as there is no electricity involved. It is also extremely convenient as there is no switching on or off required, you get hot water all the time.
Is There Any Maintenance Required?
Solar water heaters are almost maintenance free. It is a passive device and there are no moving parts.
Are There Any Subsidies From The Government?
The Ministry of New and Renewable Energy (MNRE) has stopped providing subsidies. You can check with your state government for incentives.
Where Can I Buy it? What Brands To Look For?
Solar water heaters are available everywhere. You can go through your classifieds and find a supplier. There is a list of manufacturers and suppliers on the MNRE website. V-Guard, Sintex, Tata, Supreme Solar, and many other brands are available.
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