Sizing your
Solar Water Heater correctly

Sizing your solar water heater correctly guarantees adequate hot water supply and prevent unnecessary over investment. The two components that you need to size correctly are the heater tank. and the collector .

Tank Sizing

If your household is 1-3 persons, the right tank size is 80 gallons
If your household is 4-6 persons, the right tank size is 120 gallons

Collector Sizing

For the first two people in your home you need a 20 square feet flat plate collector If your home is in the Sun Belt States you need 8 additional square feet for every additional family member.
If however you live in the more northern state you’ll need 14 additional square feet for each additional family member.

Evacuated tubes collectors size is measured by the number of tubes, you'll find sizes between 20 to 40 tubes.

A reminder - if you do live in a northern states and if temperatures bellow freezing (32 degrees) are expected - you need to have anti-freeze fluid to flow in the loop between the collector and the heater tank. You need to have a heat exchange in your tank. a pump is another element that should be added

If for some reason you can't install the tank above the collector even though you might live in the Sun Belt states you'll need to have an active solar heater. It means a pump is required as well as the tank and the flat plate collector. You can however run water in the loop between the flat plate collector and the tank.

If you live in the really northern states, you will need to consider evacuted tubes collector and not a flat plate collector