Ordinarily, solar collectors convert the solar energy to electricity, direct current. Some of this is sent to batteries for storage. This electrical power is then converted to alternating current by an inverter in order to power lights, other small appliances, stove tops, microwave ovens, refrigerators, and possibly heating and cooling houses.

On the other hand, it is possible to do some of this without conversion to electricity. One can employ solar collectors that produce heat. This can be used for cooking directly, it can also be used to heat and cool a house and produce hot water without a whole lot of electrical power. In addition, sunshine can be brought into a house to produce light by the use of windows, skylights, etc. This brings us to the issue of design for passive solar heating. Some issues in this regard are the use of overhangs and massive building materials (e.g., stone and concrete and water) for the storage of the solar energy (i.e., the flywheel effect). There are high tech devices that can be used to store the heat (i.e., tanks containing salts).

I am not sure , if it can be a total substitute, although it can compliment the conventional way of electricity, depending on the system used.

I would be willing to consider it depending on cost.

Solar hot water is the best investment Sir, I say no more.