Hot water heaters don't last forever. Ten years is about when you have to consider replacing them. In 15 years, a replacement is generally past due.
The good news is that there are newer hot water heater technologies to consider. The newer technologies are often more efficient, cheaper to operate, and better for the environment.
First, let's consider my favorite: the tankless heaters. They are better for the environment because they heat water only upon demand. There is no waste with this technology. And because they don't store hot water awaiting use, tankless heaters save the energy needed to maintain stored water at the desirable temperature.
Tankless heaters only heat water upon demand. When the tap is turned on, water is heated in the unit and then delivered to the user.
They are either gas or electric powered. Traditionally, but perhaps less so today, gas has been a cheaper choice. And gas seems to heat the water more efficiently.
What's the downside? Capacity. Because the tankless unit is producing heated water only on demand, there is a limit to the amount of water that can be produced per minute.
Modern units seem to range between two to five gallons per minute. Which is great for a small household, but may cause a problem for a larger household with a presumably higher demand.
Capacity limits become more critical when two applications occur at the same time. For example, there may be a capacity problem if one person washes dishes while someone else is taking a shower.
A suggested solution is to install more than one tankless water heater to supply the entire house. Or, you can install a tankless heater to support particular uses – such as one for your washing machine, another for your shower, etc.
This last option might be optimal because the heaters can be sized per application and because capacity issues disappear.
Of course more units means more upfront costs. Not to mention more maintenance costs.
Also, there is a potential problem concerning pilot lights for gas powered tankless systems. The gas required to maintain a pilot light may eat away at the energy savings by going tankless in the first place. Some units have pilot ignitions that solve this problem.
There are two other technologies that you should also consider when purchasing a water heater. Tankless coil technology is powered by the heater used to make your house warm. It is most efficient during the months that you use your home furnace on a regular basis.
Likewise indirect water heaters are also powered by your home's heating furnace, but rely on a tank. These systems are usually sold as integrated appliances, but retrofits are available.
The internet has many government sources which will help you examine your options. When choosing your system keep in mind the kinds of things you always need to keep in mind -- your own use needs, the reputation of the manufacturer, the dealer and the installer, and warranty issues.
Referrals from people you know and trust are always a good idea. One thing that is for sure -- these aren't your father's hot water heaters anymore.