Water Heater

Water heaters are a modern necessity and heat water through several different methods, and some methods are much more cost effective than others. This site will explain the differences between the different types of water heaters so that you can decide which system is best for you and where you can buy it.

Meet Cool Friends-Avatar,Pics,Chat!

Water Heater - Basics
A water heater is a device for heating and storing water. Heat is generated by gas, electric, or steam. In industrial usage, large water heaters are called boilers.

Types of Water Heaters

Tank heaters

In household and commercial usage, most water heaters are of the tank type. These consist of tanks in which a given amount of water is kept continuously hot and ready for use. Typical sizes for household use are 20 to 40 US gallons (75 to 150 L). These may run on electricity, natural gas, propane, fuel oil, or other energy sources. The most popular in the United States is the natural gas type.

Tank-type water heaters can be made more efficient by installation of additional insulation jackets around the tank, flow valve devices at their inlet and outlet, cycle timers, electronic ignition (in the case of fuel-using models), sealed air intake systems (in the case of fuel-using models), and pipe insulation. The sealed air-intake system types are sometimes called "band-joist" intake units. "High efficiency" units can convert up to 98% of the energy in the fuel to heating the water. The exhaust gases of combustion are cool and are mechanically ventilated without the need of a chimney.

In British English, water heaters are known as boilers, or "Geysers" (pronounced "geezers"), feeding a separate hot water tank. Such tanks are often fitted with a backup electrical heater for a quick boost, known as an immersion heater. It is mandatory that these hot water storage vessels are 'indirect'. That means the water from the boiler circulates via a separate internal exchanger and does not come into contact with the stored hot water. (It is common for first time American users to burn themselves if not warned.)

Tankless heaters

Tankless water heaters, also called instantaneous, inline or instant-on water heaters, are also available and gaining in popularity. These water heaters heat the water as the water flows through the device, and do not retain any water internally except for what is in the pipe. Tankless heaters may be installed in at faucet or bathroom that is far from the central water heater or larger models can be used to provide hot water for the entire house.

Tankless heaters can be far more efficient than storage water heaters. In both kinds of installation, the absence of a tank saves energy as conventional water heaters have to reheat the water in the tank as it cools off. With a central water heater of any type, water is wasted waiting for water to heat up because of the cold water in the pipes between the faucet and the water heater.

Point of use tankless water heaters are located right where the water is being used, so the water is almost instantly hot, which saves water. They also save even more energy than centrally installed tankless water heaters because there is not any hot water being left in the pipes after the water is shut off. However, point of use tankless water heaters are usually used in combination with a central water heater, as the expense of buying a heater for every kitchen, laundry room, bathroom or sink, often outweighs the money saved in water and energy bills. In addition, point of use water heaters are almost always electrical, and electricity is far more expensive than propane and natural gas.

The most cost effective configuration is usually to use a central tankless water heater for the most of the house, preferably natural gas, and install a point of use tankless water heater at any distant faucets or bathrooms. However, this may vary according to how much electricity, gas and water costs in the area, the layout of the house and how much hot water is used. Only electric tankless water heaters were available at first and they are still used for almost all point of use heaters, but natural gas and propane heaters are now common.

Since the water must be heated instantly, the tankless water heaters use a lot of electricity or fuel while they are on. If a storage water heater is being replaced with a tankless one, the size of the electrical wire or gas pipeline may have to be increased to handle the load.

Solar heaters

In some locales, solar water heaters are used. These are installed outside dwellings, typically on the roof or nearby, and consist of a tank and of a panel in which water circulates. The tank and the panel are painted a dark color in order to maximize the reception of solar heat.

How it Works
A gas water heater is nearly identical to an electric water heater, except that it does not contain the two heating elements, but instead has a gas burner at the bottom, with the chimney running up through the middle of the tank.

A water heater consists of the following parts, as shown in the figure above:

A heavy inner steel tank that holds the hot water

Typically, this tank holds 40 to 60 gallons. It has to be able to hold the pressure of a residential water system, which typically runs at 50 to 100 pounds per square inch (psi). The tank is tested to handle 300 psi. The steel tank normally has a bonded glass liner to keep rust out of the water.

Insulation surrounding the tank

A dip tube to let cold water into the tank

A pipe to let hot water out of the tank

A thermostat to control the temperature of the water inside the tank (Many electric water heaters have a separate thermostat on each element.)

Heating elements to heat the water (These are the thick electric elements similar to those you see inside an electric oven.)

A drain valve that allows you to drain the tank to replace the elements or move the tank

A pressure relief valve (This is an important safety feature that keeps the tank from exploding.)

A sacrificial anode rod to help keep the steel tank from corroding

The Techniques
The thermostat controls the temperature of the water inside the tank. Normally you can set the temperature between 120 and 180 degrees Fahrenheit (49 to 82 degrees Celsius). It is generally recommended that you keep the temperature between 120 to 140 degrees F (49 to 60 C) -- especially if there are children living in the house -- to prevent scalding. It also saves energy.

Normally, the thermostat is underneath a cover plate and it has a knob or a screw that you can use to set the temperature

A water heater uses nothing more than the "heat rises" principle to separate hot water from cold water in the tank.

As cold water comes in, it remains at the bottom of the tank because it is denser than hot water. If you use the hot water faster than the heating elements can heat the incoming cold water, and if you consume all of the hot water that the tank holds, you run out of hot water in the middle of your shower. If this seems to happen too often, it could mean that the bottom heating element in an electric water heater has burned out or that your water heater is too small for your house. Or it could mean that you are taking really, really long showers.

Critiques
One of the most common household plumbing projects is replacing a water heater. Normally, the first sign of a heater problem is water dripping from the bottom of the jacket. This indicates that the tank has corroded through. the cure is installation of a new heater. Nothing last forever so if you own a home be prepared to have a water heater replaced at some point.

Most Popular Water Heaters
Rheem Water Heater#br>AO Smith Water heater#br>Rinnai Water Heater#br>Bosch Water Heater#br>Bradford White Water Heater#br>GE Water Heater#br>Whirlpool Water Heater#br>American Water Heater#br>Richmond Water Heater#br>Atwood Water Heater

Money Saving Tips
Since most water heaters last up to years, here are some money saving tips to get the most out of your heater:

Install aerators in faucets and low-flow shower heads. They may reduce your hot water consumption by half.

Repair leaky faucets and shower heads. A leak of one drip per second can cost $1 per month.

Insulate your hot water storage tank and pipes, but be careful not to cover the tank thermostat(s).

Lower the thermostat(s) on your water heater to 120°F. Electric water heaters often have two thermostats, one each for the upper and lower heating elements. These should be adjusted to the same temperature to prevent one element from doing all the work and wearing out prematurely.

If you have an electric water heater, install a timer that automatically turns the hot water off at night and on in the morning. A simple timer can pay for itself in less than a year.

Install a heat trap above the water heater. It’s a simple check valve or piping arrangement that reduces standby losses by preventing "thermosyphoning," the tendency of hot water to rise up from the tank into the pipes.

Drain a quart of water from your hot water tank every three months to remove sediment that prevents heat transfer and lowers the unit's efficiency.

Take more showers than baths. Baths use the most hot water in an average household. You use 15 to 25 gallons of hot water for a bath and less than 10 gallons for a five-minute shower.

Before You Buy
Here are some tips on buying a new water heater:

Although many consumers buy water heaters based only on the size of the storage tank, the first-hour rating (FHR), provided on the Energy Guide label, is actually more important. The FHR is a measure of how much hot water the heater will deliver during a busy hour. A larger tank doesn’t necessarily mean a higher FHR. When you buy a water heater, estimate your household’s peak-hour demand and look for a unit with an FHR in that range.

If you live in a moderate climate (i.e., with relatively low heating loads), consider a more efficient heat-pump water heater (HPWH). Although an HPWH may have a high initial cost, it can save up to 50 percent of your water heating bill.

For energy efficiency as well as safety, when buying gas- or oil-fired water heaters look for units with sealed combustion or power venting to avoid back-drafting of combustion gases into the home.

Everything else being equal, select a water heater with the highest energy factor (EF), the measure of a water heater’s efficiency. EF is based on recovery efficiency, standby losses, and cycling losses. The higher the EF, the more efficient the water heater. Electric-resistance water heaters have an EF ranging from 0.7 to 0.95; gas water heaters from 0.5 to 0.6, with a few high-efficiency models at around 0.8; oil water heaters from 0.7 to 0.85; and heat-pump water heaters from 1.5 to 2.0.

Whenever possible, do not install the water heater in an unheated basement. Also try to minimize the length of the pipes that must be run to your bathroom and kitchen.

Extended warranties and new energy-efficient designs are features to look for when shopping for a water heater. Many water heaters have eight- to 10-year warranties and some are warranted not to leak for as long as you own your home.


Additional Links

Kitchen and household appliances
Appliance Parts Depot
Kitchen Appliances and Replacement Parts
Heating Ventilation and Air Conditioning
Kitchen Items


Local Articles
Home Appliances
Home