Passive solar water heater can be easily built as a do-it-yourself (DIY) project and they are fairly cheap to build. One can easily make one using a good solar water heater plan with other inexpensive raw materials which are usually available at home or in stores.

These hot water heaters are more dependable and are extremely economical in the long run.

Passive or Batch Water Heaters as they are also called do not use pumps or any other controls to transfer water. Instead, it uses gravity and other natural forces which circulates the water.

Generally a batch water heater consists of a a tank which is painted black to easily absorb the solar rays in the form of heat. This absorbed heat is used to heat the water stored in the tank. Also an insulated box is used to cover this tank so that the heat remains intact and does not cool down.

This pre-heated water is then passed via a conventional water heater for further heating if necessary.

In summers, the hot water collected in the solar tank itself is sufficient for domestic use and the conventional heater is not required then.

In winter, pre-heated water may be required to be heated again to the required temperature. Even if a conventional heater is put to use, since the water is pre-heated considerably, the amount of heating required by it is considerably less.

You can now easily see that passive solar heaters can easily fulfill the hot water demands of the household for most of part of the year without any further expenses.

For the remaining small part of the year, even if water needs to be heated using the conventional way, since the water is almost heated up, the expenses are going to be absolutely minimum as compared to the expenses borne by a household in heating cold water.

As is obvious by installing a solar hot water heater, you can easily save up to one-third of your energy costs.