Water Heaters: Tankless vs. Conventional

By Frank G. Ross

Water heater – the name says it all.  It’s a device to heat water.  Traditionally, a water heater consists of a storage tank with heat source, usually gas or electric.  However, tankless water heaters, widely used in Europe and Japan, offer on-demand hot water and lower water heating costs.  Due to their small size, these units can be installed under a sink or on a wall, resulting in space savings for the homeowner.  The larger models are best used in place of a storage tank to supply hot water for the entire home; while small point-of-use water heaters can work in conjunction with a home's existing tank system.

Besides gaining extra floor space, the homeowner also gets an unending supply of hot water since it is heated at the unit on demand. Of course, it only makes sense that water that travels a distance from the heater to the tap will take a short while to reach the tap, but for point-of-use models, hot water is instantly available.

One of the most frequent homeowner complaints is running out of hot water when hot water is needed by two separate appliances or for a long period of time, such as when two or three family members take showers one after another. A properly sized tankless water heater provides a constant supply of hot water and can keep up with hot water draws from multiple fixtures.

A common misconception of tankless heaters is that they require a lot of energy to elevate the water temperature to the required temperature on demand, but because a tankless unit doesn't have to continuously heat water sitting idle in a tank, it's actually very efficient. From the moment the unit's heating system is activated, it provides a constant supply of hot water.   But, when hot water is not needed, the heater essentially powers down into standby mode, saving energy usage and costs.

The biggest draw to tankless heaters for most homeowners is cost savings.  Homeowners can realize significant savings in water heating costs from tankless heaters over traditional ones due to their efficiency. (AS LONG AS you don't take longer showers that you used to take) The initial cost can deter homeowners and contractors, although the lifespan of a tankless unit is usually at least five years longer than tank-type heaters, which means it should far outlive its payback.

A tankless system is something to consider when remodeling a kitchen or bath or when replacing the home's existing water heater. Another advantage of tankless heaters is that the electric units require no venting and the gas units can be vented through a sidewall which is appealing to homeowners who would like to avoid adding roof vents.

Water heaters work year after year with very little maintenance, so it is easy to ignore them.  Yet routine maintenance checks should be performed on all types of water heaters.

Your conventional water heater will work better and last longer if you get rid of sediments that accumulate in the bottom. These sediments shorten heater life, reduce capacity, and insulate the bottom, forcing you to pay for more energy. Every six months run a garden hose from the drain valve to an outside door, sink or drain. Open the valve and let it run for three or four minutes, then turn it off. That’s it!

The pressure and relief valve located on a water heater has a lever on it for testing purposes. Before testing the valve be sure there is a proper over flow pipe attached to the relief valve. Every couple of years you can test the relief valve by raising the handle on the valve ever so slightly.  If all is well you will hear a slight hissing sound, then release the handle. If there is no sound, or the relief valve is missing or the discharge tube is missing then please call a plumber as soon as possible. If the valve continues to leak after you have released the handle then the relief valve will need to be replaced. Two or three times I have seen a metal plug screwed in the place where the relief valve should be. This is a very serious hazard.   The water heater should be shut off immediately and a plumber called out to correct this without delay.

Routinely check your water heater for rust and leaks.  A leak is a sign that the water heater is nearing the end of its lifespan and you will need to replace the unit soon. 

Bracing a water heater tank is smart and an inexpensive move. During the 1994 Northridge, California quake 60% of home fires were the result of a fallen water heater. Even in a light quake, a water heater can move enough to rupture gas or water lines, causing fire or flooding. Hardware stores may have a bracing kit for your water heater. Be sure you have flexible supply tubes for hot and cold water. With simple tools and a couple of hours the bracing kit should be easily installed.

 As with any repairs or upgrades or maintenance, if you feel you are not qualified for the job then by all means hire a professional to do the work for you.

Frank Ross is a Certified Utah Home Inspector for Pillar to Post Professional Home Inspection and a full member of the National Association of Certified Home Inspectors and a member in good standing with the Utah Better Business Bureau.  Readers may contact Mr. Ross at (435) 867-6400 or frank.ross@pillartopost.com or www.pillarposthomeinspection.com