Water Heaters

Residential Water Heater

In the home, water heaters are among the most indispensable appliances. Considering that water heaters can last up to 20 years, the unit currently found in your home may have some miles on it. When you're shopping for a replacement water heater, there are four primary criteria besides cost that you should consider:

First, you should select the most energy efficient water heater for reduced energy use and long term savings. Second, take into account the space the unit will fill, and third, consider its durability. Lastly, be sure to examine the different safety features. And while price is always important, remember the true cost will be spread out over the long life of the heater.

Finding the Right Water Heater

You know you should consider energy efficiency, size and durability and safety when selecting a replacement water heater.

In terms of efficiency, you should look for a water heater with a high first hour rating (FHR). This is a measure of a water heater's performance from the start. In other words, how much hot water can it provide starting from an empty tank. It will indicate its reliability during high-volume use.

Also consider the energy factor of the unit, which measures efficiency. This number will usually be a fraction such as .85, but it can be higher.

Durability is not always a given, but with trusted brands you should expect it.

When you consider size, size, storage type units are much larger than tankless units which can be wall-mounted.

Some water heaters, such as heat pump units, need at least 1,000 cubic feet surrounding them while others will function safely in a closet.

Above all else, safety is important. A gas water heater should have a sealed combustion chamber. Direct-vent or power-vented units help to dissipate excess heat and fumes. Look for units with safety features built in such as auto overheat protection and a carbon monoxide sensor for gas units.

Water Heater Options

Replacing a water heater, you have two main options. You can either go with a conventional storage tank type water heater or opt for a tankless, demand water heater.

In residential applications, storage tank type water heaters range in size from 20 to 80 gallons, although 20-gallon units will serve only single-dweller homes.

Tankless water heaters, just as their name suggests, use no storage tank. Instead, they heat water instantly as it is demanded. Both types have their merits and their drawbacks.

The next major choice you have to make is the fuel type. Water heaters are fueled most commonly by electricity and natural gas, but liquid propane and fuel oil are used as well. Access to fuel may determine the type you use. If you do not have a natural gas to your home, installing one will be initially expensive, so you might opt for an electrical unit.

Storage Tank Water Heaters

Now that you have an idea of what to look for when replacing a water heater, it's time to look at the different types available. If you are considering a storage type unit, you have a choice between conventional electric resistance, gas combustion, gas condensing, oil-fired and heat pump water heaters.

Those types with the highest energy factor (EF) are heat pump units and high efficiency electric units. Next efficient are gas condensing units, followed by gas combustion and oil-fired water heaters. Heat pump water heaters draw in warm air and transfer its warmth to the water, easing the strain put on the heating elements. This makes them the most efficient, but they also require adequate space and cannot be installed in cold rooms.

The size of storage type water heater you choose should reflect your home hot water needs. Storage type water heaters can suffer from standby heat loss; heat energy loss occurring because heated water is not immediately used. A well-insulated tank and one that is not too big for your needs can help to mitigate this energy waste.

Tankless Water Heaters

Thanks to their compact, lightweight size, relatively easy installation and instant hot water-heating ability, tankless water heaters are becoming more popular. Moreover, tankless units provide an endless supply of hot water.

The recovery rate of hot water is measured in terms of gallons per minute (GPM). When a hot water tap is turned on, cold water moves through the tankless water heater where the gas or electric heat exchanger immediately heats it and channels it to the tap. As the demand for hot water increases, the water flow rate reaches its maximum potential.

Tankless units can serve a whole house, while smaller varieties make excellent point of use water heaters. For example, a unit installed under a sink providing hot water just for that sink. Usually heating water in stages, tankless water heaters have a minimum flow rate of around .6 and can reach 9.8 GPM or higher depending on the unit and other conditions.

Tankless water heaters do not suffer from standby heat loss, for they produce no standing hot water. Gas units that feature a standing pilot light can, however, waste fuel on the light, so look for a tankless unit with a direct ignition system. In general, electric tankless water heaters are more efficient, although with advancements in technology this is not always the case.


While cost is an important factor, more important is getting the right water heater for your home's needs. You can spend well over $1,000 on a new unit, but you can also spend as little as $250. Since you could live with the heater for many years, tt is vital to select a unit that is the right size for your house and is highly energy efficient for the fuel type available.