The Low-Cost Solar Heating System (Aquecedor Solar de Baixo Custo - ASBC) is a technology suited for tropical and sub-tropical climates, extracting the energy present in sunlight to pre-heat water destined for domestic bathing, typically in shower-baths equipped with electric shower-heads. The technology is entirely explained in the ASBC manual, available for download, in English, on this site The collector panels are plastic (PVC), without traditional insulation materials or the glass covering plate used to increase the temperature of the water circulating in the panels. For this reason, the ASBC panels do not reach the high temperatures of traditional solar panels, thus avoiding weakening or destruction of the PVC material. But, the use of PVC also provides a large reduction in the cost of materials. [It must be noted that on a sunny day the ASBC water reaches about 60 degrees °C, much higher than is considered comfortable for normal bathing (about 32°C).] This technology using PVC is not recommended for use in rigorous temperate climates, such as Northern Europe or Canada, where freezing temperatures or snow may occur.

Here are some considerations about Brazil, for which the ASBC was developed:

• Almost all Brazilian dwellings, be they small houses or large buildings, have water storage tanks high in the building structure. The water from the public mains goes first to these tanks, and then from the tanks to the points of use.
   
• PVC piping is almost exclusively used for fresh water supply and used water disposal. Thus plastic pipes and fittings are readily available at reasonable cost.
   
• Shower-stall bathing is the norm. Bathtubs are seldom used. Bathing water is usually heated by electric shower heads, which turn on only when the shower faucet (valve) is opened. These can be of 110 V or 220 V. with power ratings of between 3,000 and 8,000 watts. Low income families normally use only this system (although middle and high-income families may also use it). Electricity used to heat shower water represents about 30% of the monthly residential light bill of low-income families. The ASBC was developed for these families.
   
• Brazilians take at least one bath per day, sometimes two. These baths typically are taken at the end of the workday, between 18:00 and 22:00 in the evening. Overall electric energy consumption is at its highest level at this time, straining the nation's generation capacity.