Solar Water Heaters have often been the step-child of the solar/clean energy industry as centralized and decentralized solar power
applications get all the attention, relegating solar water heating systems to a footnote in the renewable energy conversation.
We are here to tell you why it might make sense to make solar water heater systems your first clean, sustainable energy investment.
1. Solar Water Heating Systems are a better choice for your terrace space than Solar Power systems.
I am sure most of you reading this are surprised. But honestly, your terrace doesn’t care much for Solar Thermal or PV. All it cares
about is how well the space is being utilized. Solar Thermal technology, specifically solar water heating technology works at 80-90% efficiency whereas Solar PV technology (PV is Photovoltaic- a fancy word for Solar Power) works at 15-20% efficiency. What this means is that a solar water heater system generates the same amount of energy in a 1m2 area which a solar power pack system takes 4-5m2 to generate.
Well you might be wondering if a solar thermal system can even be compared with a solar power technology since the former is used to heat water whereas the latter is used to generate electricity. Fair point. But in terms of energy conversion all that matters is what goes in and how much comes out and the overall usefulness of the system.
In solar water heater systems, 100 units of solar energy go in and about 80-90 units are converted into useful energy. The comparable
number for solar power systems is only 15-20 units.
(Btw, your car engine works at about 35% thermal efficiency)
2. Solar Water Heaters utilize a renewable and green Energy source
This may seem obvious. But here are the hard facts.
A family of four (two adults, two children),using an electric geyser which runs on a non-renewable source of electricity (like a coal powered thermal power plant), generate about 3kgs of CO2 every day. That may only be about 1095kgs of CO2 in an year but it works out to about 43 Metric Tonnes of CO2 during a 40 year period!
Solar water heaters, in comparison, run on a green energy source – The sun and, have a minimal carbon footprint.
And here’s why…
3. They consume no electricity or fuel.
Let’s go back to our family of four using an electric geyser for their bathing needs. Their electricity consumption from a single day of use is about 9kWh. This works out to a monthly cost of Rs.2700 and an annual cost of Rs.32,400 in electricity bills, assuming conservative tariffs.
Take a 200 Litre ETC solar water heater system. It costs about Rs.30,000 to purchase and install and the cost of the system pays back within an year of installation from the electricity savings. Solar Water Heaters are the way to go.
But what about the cost of maintaining the system and other operating costs?
4. Solar Water Heaters have next to zero operating costs
Yes. That is right.
These systems are zero maintenance due to the absence of any moving, electrical or electronic parts although, periodic maintenance is recommended for areas with hard water conditions.
This is uncommon in cities but common in up-country locations. In either case, the maintenance costs are minimal and you can get an Annual Maintenance contract for dirt cheap from the company you purchase the water heater from.
The occasional use of electric backup heaters during monsoons does result in minor increase in operating costs but these are minimal and for days with heavy rainfall only. Solar water heaters are mightily efficient even in diffused sunlight.
5. They work during power cuts
If you’re getting late for work and your local electricity board has scheduled a load shedding on the same day, there is no cause for
worry. You can still enjoy a nice, hot shower, put on your best suit and head out to work.
All of this without wasting much time because…
6. SWHs offer a near instantaneous source of hot water
Of course, this, to an extent, also depends on how good your plumbing line is. With modern composite pipes, heat loss from plumbing lines is minimal and it is safe to say that solar water heater storage tanks are able to deliver 90% of the hot water output at their outlet to the bathrooms.
7. They work during continuous periods of no sunshine
Solar water heaters have large, insulated storage tanks. There is a main tank which stores the water followed by a layer of Insulation, usually PUF or Rockwool, and then a final layer of a PPGI/SS/Aluminium outer cladding to cover the insulation and give a good finish to the product.
These layers of insulation are often 50-75mm thick, thick enough to hold the heat within the water for 3-4 days with minor heat losses overnight, making them ideal for regions with continuous periods of heavy rainfall.
8. Highly suitable for varying water conditions
With the degrading and highly variable quality of water across the country, water heating systems need to be robust enough to survive at least 7-10 years in such conditions. Traditionally, solar water heating systems were made of Mild Steel with no coating. This led to these systems corroding within 3-4 years of use.
With advances in technology, solar water heating systems, these days, are largely made of Galvanised Iron (GI) or Stainless Steel (SS). The steel is usually covered with a corrosion protection coating such as enamel, epoxy, powder coating, etc to prevent salts, chlorides, iron, etc in the water from corroding the underlying metal.
Some companies also offer systems which are baked in an oven to ensure the coating adheres better to the tank, ensuring a long life. It is common to see solar water heaters come with 5, 7 or 10 Year Warranties.
9. Solar Water Heating systems come in Multiple capacities
A family of four may need a much larger solar water heating system than a family of two. Similarly, if you have guests coming over often you may need to build some emergency capacity. If you are used to bathing twice in a day, this needs to be budgeted. Likewise, if your solar hot water system is to supply three bathrooms instead of one, the plumbing heat losses may be higher and must be compensated for.
Considering these needs, solar water heaters come in variable sizes – 100,125,150,200,250,300,400 and 500LPD are the common ones. If you are not sure what size of solar water heater you would need for your house, you can use this handy calculator which we have built for you.
10. Ideal for pressurized Applications such as Rainfall shower heads
If your home has a rainfall showerhead chances are you relish the idea of a hot water shower early in the morning or late in the evening
Sometimes though, the absence of instantaneous hot water can be a real mood killer. Even worse is if your architect designed rainfall shower heads for your bathroom,but forgot to put a pressure boosting pump, and your water still trickles out from the
shower, killing the experience of the bath.
Solar water heaters combine the world of high pressure with instantaneous hot water to give the ideal bathing experience for home owners. Some solar water heating systems are designed to operate at even upto 10 bar pressures and are often sold with booster pumps and safety valves.
The company from whom you purchased the water heater can install the system on your terrace. The technician or even your plumber can then complete the installation of the system by integrating it with your home’s plumbing lines to ensure you have seamless delivery of hot water through your rainfall shower heads.
Which leads us to the fact that…
11. Quick and easy to install
One of our partners at Solar Hitech, timed the solar water heater assembly process over a four year period. Here are the statistics for a
100LPD system (suitable for a family of 2):
- 2016 – 30 minutes
- 2017 – 20 minutes
- 2018 – 18 minutes
- 2019 – 16 minutes
Even at 20-30 minutes, a solar water heating assembly is pretty darn fast. Larger capacity systems do take slightly longer.
If the water heating system is to be integrated into an existing plumbing line, a 100LPD system can be completely commissioned within 1-1.5hours.
12. Have a long life
A lot of this depends on the water quality. In areas with moderate to good water quality, solar water heaters can last more than 15 years. Even in areas with bad water quality, these systems last atleast 7-10 years. This is still much cheaper than owning an electric water heater or gas geyser which have comparable life spans but with substantial operating costs during their lifetime.
13. Easy and cheap to replace at the end of their lives
Solar FPC collectors and ETC Tubes, the devices which are responsible for absorbing the heat energy from the sun, have long lives, much longer than the solar water heating tanks. ETC tubes have significantly longer lives because of the vacuum created between two concentric tubes which admits heat from the sun and prevents heat loss due to the convection. This is the reason why ETC systems are highly efficient even after 15 years of use.
As a result, replacement costs at the end of the life of a solar water heating system often consist only of tank (and sometimes the
stands) which is about 30-40% of the original cost of the system, minimizing the cost of replacement.
The ETC tubes, in the event of a breakage, are also very cheap to replace costing only about Rs.600-800 per tube to replace. The space between the concentric tubes eventually lose their vacuum and have to be replaced but much, much later.
14. Property Tax Rebates and property value appreciation benefits
Besides reducing your carbon footprint, electricity costs and maintenance costs for a water heater, solar geysers also help you save a
little more on your property taxes if you are a home owner.
Municipal Corporations in many cities in India such as Pune, Ahmedabad, Rajkot, etc are offering upto 10% property tax rebates on
installation of solar water heating systems.
Presence of solar water heating systems on your terrace also increases the resale value of your property considering the lifetime benefits a potential house owner could get from such a system.A comparison of property values in India will show that new buildings/villas which have pre-installed solar water heating systems sell for much higher values than those without any.
15. You make the world a better place
This last point is probably the single biggest reason why you should install a solar water heater in your home. We live in a world in
which global warming and climate change are real challenges. The standard of living of future generations depend on the choices we make in the present.
Sustainable energy practices help create a greener world and make our world a better place for us and future generations to live. Installing a solar water heating system in your homes and promoting the use of sustainable energy on social media forums is a small step towards building a better planet.
Solar water heating systems offer significant benefits over conventional electric and gas water heaters. They can be used for multiple applications, have lower life time costs, long lives and significantly reduce your carbon footprint.
Given these benefits, we recommend solar water heaters to be your first clean, sustainable energy investment for your home.