The correct installation of a water heater plays a key role when it comes to how long it will last. Some homeowners decide to attempt the installation themselves in order to save money, but they may soon realize that it requires a lot more skill than they thought, particularly with tankless gas water heaters. Water heaters must be installed in an upright position and in a well-ventilated area. You should not install a water heater in a location that could suffer flood damage as this can cause the exterior pipes to rust, decreasing their efficiency and lifespan. Another thing to keep in mind is that at some point you will need to have the water heater inspected so it should be placed in an easily accessible area.
The amount of use the water heater gets is another thing that will significantly affect its lifespan. Logically, the more water that has to be heated, the more stress this will put on the water heater as this means it has to work that much harder.
The quality of the water heater is another major factor that will determine its lifespan. As is the case with the majority of things, you get what you pay for, so a more expensive water heater is likely to last longer than a cheaper alternative. An easy way to tell if the water heater is of good quality is by checking to see how long the warranty lasts. Water heaters that come with a longer warranty tend to be constructed better which means they will have a longer lifespan.