10 to 13 years
It all depends on how much the tank holds and the wattage of your heater I like to have 10 wattage for ever gallon so if you hVe a ten gallon tan you need a 100 watt heater al … so the temperature of you want will make a deference normally my 20 gallon tank can go from 46F to about 77 F in two hours. While standard units with tanks that hold and heat large amounts of water last approximately 13 years, tankless or on-demand heaters -- either gas or electrically heated -- can last up to 20 years. While no one can determine exactly how long a water heater should last, a properly maintained, quality water heater can last 8 to 10 years. Of course, many factors will affect the lifespan, including electricity irregularities, the quality of the water heater, and the mineral density in the water. How long a water heater lasts depends on how well it is maintained, the water quality in your area, proper installation, and amount of use. When you buy a water heater, it's always good to look at all of the information that comes with it. That way, you will know what to expect. Lifespan. While a typical tank water heater is supposed to last 10 to 13 years, tankless water heaters are estimated to last up to 20 years. If you're planning to stay in your home for a while, that's a hefty replacement fee you're saving. How long do tankless water heaters last? Tankless water heaters typically last 15 to 20 years, compared to 10 years or less for a tank-type water heater. If there are very hard water conditions, water treatment will be important in maintaining the life of th So when you buy a water heater that is guaranteed to last for ten years it will probably last for twelve. Considering that the average family has a forty gallon water tank and uses quite a bit of hot water, it's worth it to get the better hot water tank and have a plumber install it.
http://www.answers.com/Q/How_long_will_a_20_lb_propane_tank_last_in_hours_on_an_outdoor_heater_set_at_medium_before_I_need_to_exchange_the_tank http://homeguides.sfgate.com/long-tankless-water-heater-supposed-last-88852.html https://www.plumbingsupply.com/why-maintain-your-water-heater.html http://www.plumbingpro.com/water-heaters-faq/how-long-should-a-water-heater-last/ http://www.apartmenttherapy.com/pros-and-cons-of-a-tankless-water-heater-176538 http://allvalleyplumbingca.com/faqs_tankless.html http://www.plumbingpro.com/water-heaters-faq/how-long-should-a-water-heater-last/
how long heater last