A significant part of the energy consumption in the residential segment is attributed to water heating. The types of fuel vary according to what is available on site; the technologies employed are also different, according to specifics of each country. Of all the final uses, water heating is responsible for a significant part of the consumption of residential energy. The different types of energy or fuel available in different countries, and the different technologies prevent us from asserting which would be the best option for heating water. One of the most employed technologies is the heating by means of electric boilers-storage tanks. This type of heating is widely used, yet consumes large amounts of energy as a result of heat losses, the installation costs are high and the process may cause the development of Legionella pneumophila. This somehow is not quite accurate since other intervening variables ought to be taken into account. Another type of water heating system used, but less known, is the electric showerhead that consists of instantaneous water heater equipment. This type of equipment, widely used in some developing countries, has a reasonable energetic efficiency at a very low cost. Therefore its advantages canceled out when the issue of high demand of electric energy arises and the bacterium proliferation case is questionable. The electric showerhead effect is here presented by means of an investigation in low-income housing.