How long do tankless water heaters last? What's their expected lifespan?

Unlike traditional tank style water heaters which only last 8-12 years on average, tankless water heaters last far longer! Electric tankless water heaters manufactured by Stiebel Eltron have a life expectancy of 20 - 30 years. Their lifespan can be extended even further by making sure that your water is filtered and not hard.