When your water heater fails it’s panic time and you need to act fast, but making an emergency purchase of such an important piece of home equipment usually has a poor outcome.
Take some time now (while your water heater is still operating) to learn about the various units available to homeowners today.
Number one…it’s important to know that costs will vary greatly depending on the type, manufacturer and installation needed. You want to buy the most energy efficient unit, at a price that is within your budget, so it’s important to become familiar with what is available today.
What to Buy…Look at the Pros and Cons
Before making a decision, take a good look at the following criteria:
You might think that the size of the storage tank is the most important criteria. However, the FHR rating on the Energy Guide label is more important. FHR measures just how much hot water you’ll receive during the first hour of use. Determine how much your household will need during a busy first hour and find a unit with an appropriate FHR rating.
A heater’s efficiency is its Energy Factor (EF). This indicates how efficiency the heat is transferred to the water, standby losses and cycling losses. EF ratings are usually in the manufacturers’ operating manuals. The higher the EF rating…the more efficient the water heater will be.
Often the cost is the most important factor when purchasing a water heater. When looking at the different types and models, analyze the costs during the life cycle of the water heater. You can find information on determining the life cycle cost from EREC.
Warranties are tricky. You need to determine how long you are likely going to have your water heater. Longer warranties equal higher costs at purchase but could equal fewer costs in the long run, if the long run matters. Add this into your cost criteria.
Following are the types of water heaters currently on the market:
Storage Water Heaters
Storage water heaters are the most popular for residential heating. They release hot water from the top of the tank when the hot water faucet is turned on. Cold water always enters from the bottom of the tank. In this way, the tank always stays full.
Storage water heaters range from 20 to 80 gallon capacity. This type of heater isn’t the most energy efficient because water is constantly heated in the tank…even if the faucet isn’t on. This is called standby heat loss. Standby heat loss is reduced greatly with more energy efficient models. These models cost much less to operate.
It is required that an Energy Guide label be placed on all storage water heaters. This label indicates the energy efficiency rating and the estimated annual cost of operating the system.
Storage water heaters operate on electricity, natural gas, oil and propane.
Demand Water Heaters
Demand water heaters do not have storage tanks. Cold water travels into the unit through a pipe and the water is heated only when it is needed from either a gas burner or electric element.
With a demand water heater, hot water never runs out but there is a limited flow rate. If your household needs hot water in different locations at the same time (doing laundry while someone is showering) then it would be a good idea to install demand heaters in parallel sequence.
Gas fired demand heaters have a higher flow rater than those run by electricity. However, electric heaters waste a small amount of energy because the pilot lights remains on even though no water is being heated.
Tankless Coil and Indirect Water Heaters
A conventional storage tank is not needed in the tankless coil water heater because water is directly heated in the hot water heating system’s boiler. Whenever a hot water faucet is turned on, water flows through a heat exchanger in the boiler. This system is very efficient during the winter months because the household heating system is always on. However, this system is not very efficient in warm climates or during summer months.
Indirect water heaters are more efficient than the tankless coil system because the household boiler doesn’t need to operate as frequently. Water flows through a heat exchanger in the boiler but it then flows to a required separate insulated storage tank.
Because the boiler does not need to operate frequently, this system is more efficient than the tankless coil.
An indirect water heater combined with an efficient boiler, creates one of the most cost efficient and least expensive ways of water heating.
Heat Pump Water Heaters
Heat pump water heaters don’t generate heat, but use electricity to move heat from one place to another. Heat pump water heaters will not work at all in cold areas. They need to be in areas with excess heat in order to operate efficiently. These systems are costly and need to be consistent temperatures of 40 to 90 degrees Fahrenheit. They can be purchased as unites with built-in water storage tanks or added on to an existing water heater tank.
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