Most water heaters last between 8 and 12 years on average, however, with proper maintenance, some can work up to 20 years. The longevity of a water heater is determined by a variety of factors, including the type of water heater, the energy source, the sort of water you have, and how well the unit is maintained.

The law requires expansion tanks in all new water heater installations in closed systems. On the supply line of a closed water system, check valves, backflow prevention devices, pressure-reducing valves, or other devices prevent water from being sucked back into the municipal water supply.

Choosing between a tank or tankless water heater for your home depends on several things:

Tank Water Heaters: These are typically less expensive to purchase and install. They're a good choice if your household has a high demand for hot water simultaneously, as they store a large volume of hot water ready for use. However, they can have higher operating costs because they continuously heat and reheat water to maintain the temperature in the tank, which can lead to energy inefficiency.

Tankless Water Heaters: Also known as on-demand water heaters, they heat water directly without the use of a storage tank. They are more energy-efficient as they heat water only when it is needed, which can lead to lower operating costs over time. They're ideal for homes with less space, as they are smaller and can be installed in more places. However, the initial cost of a tankless system is higher, and it may require larger gas lines or more electrical capacity, increasing installation costs.

Consider your household’s water usage, budget for upfront versus long-term costs, and available space when deciding which type is best for your home.

The cost differences between tank and tankless water heaters can vary significantly. Typically, tank water heaters are less expensive upfront, ranging from about $300 to $1,200 depending on capacity and efficiency. In contrast, tankless water heaters generally cost between $600 and $2,000, not including potential additional expenses for installation which can be more complex due to the need for upgrades like larger gas lines or additional electrical circuits.

While tank water heaters have a lower initial cost, tankless models are more energy-efficient and can lead to lower operating costs over time, potentially offsetting the higher initial investment. The choice between the two should consider both these cost factors and the household's hot water usage patterns.