A water heater is a storage tank that, yes, heats water. The heat is either produced by burning gas or by using electricity. A boiler, on the other hand, can heat water that is used to heat the home and provide hot water. A different type of boiler can heat the water to the point it turns into steam.Click to see full answer. Similarly, it is asked, do you need a boiler and hot water heater?Boilers can be used to not only heat water, but also heat your home and even generate power. Boilers heat water very quickly, and like hot water heaters, are available in tanked and tankless versions. However, unlike hot water heaters, some boiler systems come with a hot water storage cylinder.Furthermore, how does a boiler and hot water tank work? The boiler heats the water and returns it to the tank higher up. When hot water is drawn from the tank, it is replaced by cold from the cold tank, which in turn is fed to the boiler. This is direct heating of the water by either a) the immersion or b) the boiler. The hot water is simply stored in the tank. Considering this, can you use a hot water heater as a boiler? An indirect water heater can be added to an existing boiler. However, it’s best to install one at the same time as you replace your heating system, since the new system can be bought with water heating in mind.What is considered a boiler?In general, a hot water heating device that stores more than 120 gallons of water, operates at or above 160psi or has a heat output of more than 200,000BTUs per hour is classified as a boiler, and must undergo all required inspections in accordance with the city of Chicago’s rules and regulations regarding boilers.