Some 37 million residential water heaters gave up the ghost and were replaced over the past five years, according to estimates by the U.S. Department of Energy. While some things get better with age, water heaters aren’t among them. In fact, the average life expectancy for a new water heater is 10 to 15 years, with the occasional stoic dinosaur making it two decades or more.

If your home’s water heater is approaching —or has surpassed — the decade mark, you may be looking at replacing it in 2015. Whether you’re proactive about it or you wait until the appliance fails completely, there are several things you should know about water heater technology, energy efficiency, cost savings and environmental impact.

 Being proactive pays — in more ways than one. Replacing an aging water heater is an investment, and you may be tempted to put it off until absolutely necessary. Replacing an old water heater before it stops working, however, has many advantages. When a water heater fails, it can leak and cause damage to your home and belongings, especially if your heater is housed in a finished basement, closet or attic. If you wait until you’re completely without hot water to begin shopping for a new water heater, you may find yourself too hurried to comparison shop.

 Learn the different types of water heaters and compare costs. Two basic types of water heaters are available for residential use: conventional storage heaters that keep water hot in a storage tank, and tankless water heaters that directly heat water as you need it. A residential, electric-powered storage water heater usually costs as little as a few hundred dollars. Gas heaters generally cost more - some models are upward of $1,000 - but cheaper natural gas prices can offset the added cost in the long run. Tankless heaters are comparably priced, but often are more expensive to install - until recently. More on that later.

 A more energy-efficient water heater can save you money in the long-term. Heating water accounts for nearly 18 percent of the average home’s overall energy use - the second largest energy expense - and costs a household $200 to $600 per year, according to the U.S. Energy Information Administration. A newer, ENERGY STAR-rated water heater will consume less energy to heat water and reduce the amount you spend on utility bills. Energy-efficient options include solar powered, high-efficiency ENERGY STAR gas or electric storage heaters and tankless heaters.

 Tankless water heaters are more “doable” than ever before. Because they heat water only when you need it, rather than keeping it hot in a tank, tankless water heaters are more energy-efficient. Still, many homeowners have shied away from switching to a tankless heater because of installation costs. Existing water and gas lines used for storage heaters don’t line up neatly and easily with most tankless water heaters, increasing labor costs. Tankless water heater manufacturer Noritz has introduced a unit - the Noritz EZTR40 Residential Tankless Water Heater - that solves the problem. Designed to replace a conventional 40-gallon water heater, the EZTR40 can use the vent, water connection and gas line already in place without moving anything to achieve a connection. The reduced labor means it costs less for homeowners to have the tankless water heater installed.

 Size matters, and it’s about to matter even more. It’s always been important to match the size of the water heater to the size of the home and the needs of its inhabitants. The National Appliance Energy Conservation Act (NAECA) - which goes into effect in April - will make size an even bigger consideration for homeowners replacing water heaters this year. Water heaters will have to meet a higher energy factor rating, which will require storage heaters to be larger. If your heater is in a tight spot, such as an attic accessed through pull-down stairs or in a utility closet, a larger storage heater might not fit in the available space. Tankless water heaters are smaller, and they may be a solution for those with space problems.
 DIY or DI-don’t? What should you do? Installing a water heater isn’t for novices, no matter what style of heater you choose. Errors can be costly, and the savings of DIY may end up costing more in the long run if you make a mistake. It pays to have a professional do the work - and with the ease of installation for the Noritz EZTR40, professional installation is more affordable than ever.