If you have a tank-style water heater, plan to replace it between six and 15 years after buying it. A tankless system lasts at least 20 years, or even longer with proper maintenance and repairs as needed.
An experienced professional installing an average 40-gallon conventional water heater into an easy-to-reach space should take two to three hours. It may take longer for large water heaters, hard-to-reach areas, or installation of new electrical, gas, or plumbing lines.
Heat pump water heaters (or hybrid water heaters) are the most energy-efficient type of water heater. They use geothermal energy from below ground to heat your water, using as little as 50% of the energy of a traditional water heater. Tankless water heaters are also very efficient, though slightly less than hybrid units.
Depending on the number of people in the household, typical water usage, and general lifestyle, a three-bedroom house can usually comfortably live with a standard 40-gallon water heater tank.