Defeating Bacteria In Hot Water Systems With A Heat Exchanger

NIST engineers developed a low-cost heat exchanger that mounts atop a residential or commercial hot water heater, allowing tank water to be stored at 70°C (160°F) to kill Legionella pneumophila bacteria while cooling the outgoing water to a safe delivery temperature using the incoming cold water supply. The prototype cost about $100 in components and preheats incoming cold water as a side benefit, potentially reducing energy waste. Legionnaires' disease, caused by this bacterium, has a 10% fatality rate and around 6,000 confirmed US cases yearly, with the true number possibly ten times higher due to underdiagnosis. The innovation targets multi-occupancy buildings like hotels and nursing homes where bacterial buildup in hot water systems is a persistent risk.

Source: https://hackaday.com/2026/08/31/defeating-bacteria-in-hot-water-systems-with-a-heat-exchanger. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.