As the hot water tanks are insulated the water in the tank stays hot through the night, ensuring that you have hot water the first thing in the morning, when you wake up.

In case of area where the input water to the solar system is hard you have the following options:

A normal solar system can be installed if the hardness of water is less than 175  ppm. The precaution that you need to take is that the system will have to be de-scaled once in a year.

If the hardness of water is more than 175 ppm, a hard water model can be installed. This is slightly costlier than the normal system. It works like a heat exchanger. The thermal liquid needs to be topped up at regular interval.

Alternatively a normal system can be installed in conjunction with either a magnetic de-scalar or water softener. Both of these are available in the market.

These specialized bath fittings require water pressure to be at 2 – 4 Kg/Cm2 (through pressure pump) therefore we need to have solar systems that can withstand this pressure. Therefore pressurized systems are to be installed in these cases. These systems have thicker shell with dish ends.

Pressurized Solar water heating system is installed when, due to head of the cold water we are unable to vent the system or the pressure pump is installed.

A 100 ltrs system, for a average household of 3 – 4 persons can prevent emissions of 1.5 tonnes of CO2 and save 2000 Kwh of electricity every year

1 KW of solar energy saves about 2500 tons CO2, 2 tons of SO2 and 10 tons of NO2.

Nearly 40% of an average household’s electricity bill goes towards heating. Payback will vary depending on the usage pattern, fuel replaced and electricity tariff in that area.

For a household of 4, the payback period : Within 2.5 years when electricity is replaced, 4 years when furnace oil is replaced & 6 years when coal is replaced. This calculation does not take into account rebates or subsidised loans. If you avail of the incentive, the payback period will be significantly reduced.

After you recover your initial investment, the savings are yours to spend in yourself and your family year after year.

The maintenance requirement are minimal. As there are no moving parts ( in thermosyphon system) there is no wear and tear, therefore no replacements or repairs. Some minor routine maintenance are be carried out. For details refer to our maintenance manual.

The expected life of the solar water heating system is anywhere between 20 – 25 years.

Application of hot water. (Bathing, Washing, Utensils cleaning, Boiler feed, Canteen etc)

No of person using hot water.

Utility of hot water ( twice a day, one time, differed through out the day etc)

Survey of the site for additional work like structure, additional cold water tank, cold and hot water piping etc)

The evaluated capacity of the solar system

The time taken for installation mostly depends on the capacity of the solar water heating system. On a average a domestic system ( Capacity 125 to 500 lpd) takes 2-3 days and a system of higher capacity ( 625 to 3000 lpd) takes 4 to 6 days.

When the water from the hot water tank is not used, then next day, on heating the temperature in the hot water rises to a higher level than what it was on the previous day. Subsequently if not is use then steam is generated. This steam is released through the vent installed on the tank. Therefore the system is not damaged in any way.

Additional precaution that can be taken is to cover the collectors with thick ( not transparent) material, so that sun rays do not reach the collectors. Therefore the system will not generate hot water.

The output temperature of hot water depends on the weather parameters on that day. The system is designed to deliver hot water at 600C during winter. The heat transfer calculation is that the rise in temperature is approximately 400C to the inlet ambient temperature of cold water. However the ultimate output temperature is entirely dependant on solar insolation for that day.

  • The minimum capacity of solar water heating system is 100 to 125 lpd. There is no upper limit to the capacity. However one should keep the following in mind:
  • For capacities below 3000 lpd → Working principle thermosyphon (generally domestic)
  • For capacities above 3000 lpd → Working principle forced flow (generally industrial


The geographical position of India is in the northern hemisphere. The sun moves to the north of equator by 150 in summer and to the south of equator by 150 in winter. The Indian Peninsular lies north of the sun when it is 150 north of equator. Therefore, the sun’s rays will always come to the Indian peninsular from the south. That is why the collectors in the northern hemisphere will always be facing south. Consequently, collectors in the southern hemisphere will always to facing north

The solar system is optimized for winter. The rays that fall perpendicular to the collector have the maximum amount of intensity. Pertinently, as the sun moves 150 south of the equator  and that the sun’s rays should fall perpendicular to it, then we need to position the collector in such a manner so that the  degree of tilt of the collector is  latitude of the place + 150.  (Pune → 18.50 )

We give below space required for system with standard capacities