How do I decide about the size/capacity of the system to be installed?


  For a house with one bathroom and 3 to 4 members, 100 liter per day capacity system should be sufficient. For more numbers of bathrooms, the capacity will increase accordingly due to pipe losses & more number of family members. Generally the capacity is decided based on hot water required in mornings for bathing. If the usage is in evening & at other times also, the capacity is decided accordingly. Some useful thumb rules for estimating the hot water requirement are given below:


Typical Requirement of Hot Water at 60OC.

Household bathing using buckets

10-20 liters per person per bath.

Household bathing using shower

with a mixing tap

20-30 liters for 10-15 minute


Shaving, while a tap runs

7-10 liters

Household bathing in bathtub (one


50-75 liters

Wash basin with a mixing tap (hand

wash, brushing of teeth, etc.)

3-5 liters per person per day.

Kitchen washing

2-3 liters per person per day.


40-50 liters per wash cycle

Clothes washing machine

40-50 liters per cycle

TypeInfo: solar basic

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