Choosing the right water heater

You should choose your water heater base on your needs. Some of the other factors that you may need to consider is the capacity, efficiency and the price.

So how do you determine capacity of a water heater?
You need to find out your household's peak hour demand period which is the time when hot water is most needed. This is considered the more important factor when come to buying a hot water heater. Find out the peak hour demand capacity or referred to as the first hour rating, FHR on the Energy Guide label. FHR is a measure for the amount of hot water it can provide during the peak hour, so it is necessary by the law to appear on the unit's Energy Guide label. So find out your FHR range before you shop for a water heater.

Gas water heaters, having the same storage capacity with electric water heater tend to have a higher FHRs. So it is possible to have a gas unit with a smaller storage tank that meets your water heating needs rather than an electric unit with the same FHR. Features in the more efficient gas water heaters that tends to use different kinds of non conventional arrangements for combustion air intakes and exhaust are usually expensive on the installation cost.

The next factor is the Rating Efficiency
After you have decided the type of water heater, you need to find out which water heater is the most fuel efficient. The Energy Factor or EF is the best indicator to find the water heat's efficiency. This is base on the recovery efficiency meaning that how efficiently the heat from the energy source is transferred to the water. And you have the standby losses, which is the percentage of heat that is lost per hour from the stored water compared to the heat content of the water. And lastly the cycling losses.

A water heater with a high EF will mean a more efficient water heater. Here are some of types of water heaters with their different range of EF.

• Electric resistance water heaters - 0.7 to 0.95
• Gas water heaters - 0.5 to 0.6. Some models have high efficiency around 0.8
• Oil water heaters - 0.7 to 0.85
• Heat pump water heaters - 1.5 to 2.0

You are usually able to locate the water heater's EF rating given by the manufacturers. If you don't locate it then you are to get the EF rating information by contacting the appliance manufacturer association. Tanks with at least about 1.5 inches or 3.8 cm of foam insulation and the energy efficiency ratings shown on the Energy Guide labels are some of the energy efficiency features you should look out for when buying a water heater.

The cost is another important factor that almost all consumers are worrying about. The price that you bought at, the maintenance and the operation expenses are the things that you will to worry about as well. When you are looking at the various models out there, a smart decision is to find out the life cycle cost, the total of all cost and any benefits that comes with when making a purchase on the unit. An expensive water heater will usually comes with longer warranties. And the cheapest water heater is also the most expensive to operate. Buying a little more expensive water heater may save you some trouble and money.

Tankless Coil and Indirect Water Heaters

The tankless coil and indirect water heaters uses a home's space heating system to heat water. Storage tank is not required in the tankless coil water heater as the water is heated directly inside the boiler in the hot water heating system. Whenever a hot water faucet is switched on, the water goes into a heat exchanger in the boiler. In the colder periods, tankless coil works efficiently because the heating system is used regularly. On the other hand, during the warmer periods, the boiler is not being use as much.

For an indirect water heater, you will need a separate storage tank. Just like the tankless coil, water is being circulated by the heat exchanger in the boiler. The heated water then goes into an insulated storage tank. As the boiler needs not work frequently, indirect water heater works more efficiently than the tankless coil. Actually, when you use the indirect water heater with a highly efficient boiler, the combination of these 2 will give you the cheapest way of heating water.

Heat pump Water Heaters

Electricity are being used by Heat pump waters heaters to move heat from one location to another rather than generating heat directly. Heat pump water heaters work similar to refrigerators just that its in reverse of the temperature.

Heat pump water heaters have a pricey initial cost because they can be bought as integral units that have built in water storage tanks or can be use as add-ons that can be retrofitted to a current water heater tank. You need to have a place where temperatures are 40 degrees to 90 degress in Fahrenheit or 4.4 degrees to 32.2 degrees in Celsius the whole year for the installation to be made. It must also contain at least 1000 cubic feet or 28.3 cubic meters of air space around the water heaters. In order to operate efficiently, heat pump water heaters should be installed in places where there is extra heat, like the furnace rooms are one example. Cold places drops the efficiency level of a heat pump water heater.

Types of Hot Water Heater

Over the last few years, various types of water heaters have become available to consumers. Right now in the market, those that can be seen mostly are: conventional storage, demand, heat pump, tankless coil, indirect and solar. You may now even buy water heaters that are join to your house space heating system. Lets take a look at some of the various water heaters we have mentioned.

Storage Water Heaters
This is the one that I mention earlier in the previous post. Hot water is draw out from the top of the tank where it is the hottest and cold water is replace at the bottom to ensure the water heater tank stays full all the time. This is the conventional form where various fuel options are available such as electricity, natural gas, oil and propane. Size ranging ranging from 20 to 80 gallons or 75.7 liters to 302,8 liters. Storage water heaters are the most popular type of water heater in the United States.

The bad side of storage water heaters is that energy is constantly being wasted every time even if you are not using, as the water need to be heated all the time. You get heat loss in standby mode. The newer and more energy efficient storage models are recommended as if can reduce your energy usage to quite a significant amount. Therefore, it is cheaper to operate. To find out the most energy efficient model, check the Energy guide label that is required on storage water heaters. The Energy Guide labels will point out either the yearly estimated price of handling the system or energy efficiency ratings.

Now lets talk about Demand Water Heaters.
Demand water heaters allows you to completely remove the standby heat loss from the tank and dropping the usage of the energy by 20 to 30 percent. This type of water heater does not have storage tanks. How it works is that the cold water goes into a pipe connected to the unit and either a gas burner or an electric elements heats up the water only when required. One thing good for sure is that your supply of hot water is always there. Never lacking.

While on the over hand, demand waters heaters have a limited flow rate. Usually, demand water heaters gives out hot water at the rate of 2 to 4 gallons or 7.6 to 15.2 liters of water per minute. Such a rate is probably sufficient when your household water usage does not use hot water at more than 1 location simultaneously. Meaning doing your showering and washing dishes at the same time. In order to meet the demand for hot water when multiple faucets are being used, you can install demand water heaters in parallel sequence. Gas fired demand heaters may have a higher flow rates than electric ones, they waste energy even when there is no water. That is if the pilots lights are turn on. But the rate of energy used by a pilot light is significantly low.

Next post we shall talk on Heat Pump Water Heaters

Water heater operation in more detailed explanation

A cold water supply line is connected to the water heater. Its usually attached on top of the appliance. Rather than replenishing the water a the top, the water is carried via a tube down towards the bottom of the tank. In the previous post, we learned that the heating element is at the bottom and hot water rise while cold water falls. So it makes more sense to replenish cold water to the bottom for the heating element to heat up the incoming cold water. And also when we draw out the hot water from the top, we get its full temperature. Once most of the warmer water at the top is being used, you start to get the less warmer water, which is a mixture of the cold and hot water.

As you turn on the hot water tap, the water pressure of the cold water supply will replenish the water heater with cold water, and when it happens, the thermostats senses the lower water temperature and the heating mechanism will be trigger.


All water heaters have a temperature and pressure relief valve that lets water escape in case the water pressure or temperature exceeds the limits of the tank. Most water heater tanks can take up to 150psi. When the pressure goes beyond 150psi, the T&P valve will release the water from the tank. If the water temperature hits 210 degrees (F), the valve will also open. The design of the T&P valve is made in such a way where pipe are connected safely bringing water away that does not flood or expose to people or pets from scalding hot water.

Right at the middle of the water heater tank contains an anode, also known as a sacrificial anode. This piece of metal will get corroded instead of the tank itself. The anode is being attacked by the corrosive action of the hot water, thus it helps to extend the durability of the water heater tank. Not only that, the water heater tank also has a bonded layer of glass to increase protection from corrosion.

Water heaters creates build up of sediment when it settles out of the water. The sediments should be check once in awhile and remove from the tank. This helps to extend the life of the appliance and improve the heating efficiency. Near the bottom of the tank, a drain valve can be found and should you should use it to remove the sediments or for draining water out of the tank.