Hot Water Heaters Guide

Choosing the right water heater

2007-11-15T05:28:00.000-08:00

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

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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

2007-11-14T07:22:00.000-08:00

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

2007-11-14T07:05:00.000-08:00

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

2007-11-13T07:14:00.000-08:00

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.

How does a water heater works?

2007-11-13T06:12:00.000-08:00

So how does a hot water heater works? The first thing you need to understand is that, hot water rises and cold water falls.

What this means is that whenever the heating element sense that the temperature in the water heater tank has drop to a certain temperature, the heating element will start to work. It will start to heat up the colder region of the water in the tank until it gets hot enough to rise above to the top. While on the other hand, the colder water will fall to the bottom of the tank where the heating element is located. The heating element will continue to heat that colder region of water once again.

So you can understand that the water heater will continue to heat the water on a regular basis. Even if you don't use the hot water, it will still continue to heat up the water as the water temperature will fall.

One point to take note is that since the water will need to be re-heated again. It is recommended to turn down the thermostat when you are on vocation or being away for long period of time, so that energy is not wasted.

Parts of a Water Heater

2007-11-12T21:46:00.000-08:00

So what does it look like inside a hot water heater tank?

A gas type water heater may look almost similar to an electric type water heater. The exception is that the two heating elements are not there. But rather, it contains a gas burner at the bottom where the chimney is run through up the middle of the tank.

So parts of a water heater consists of the following:

A heavy inner steel tank that carry the hot water 40 to 60 gallons of water are usually held inside. The residual water inside contains pressure where the tank must be able to hold it. The pressure of the water is usually about 50 to 100 pounds per square inch(psi). The tank is made to be able to handle 300psi. And inside is made with a glass liner to keep the rust from getting into the water.

An Insulating surrounding the tank

A dip tube to allow cold water into the tank

A pipe to allow hot water out of the tank

A thermostat for controlling the temperature of the water. While for most electric water heaters usually have a separated thermostat on each element.

Heating elements that heat up the water. The big looking metal things inside the tank are the elements that looks like the ones in an electric oven.

A drain valve that lets you drain the water out so that when you can replace any elements or moving the tank.

A pressure relief valve. This is a very important part of a water heater because it prevents the tank from exploding by control the pressure.

A sacrificial anode rod that keeps the steel tank from corroding.

So there you have it. Knowing the parts of a water heater tank should make you one step nearer to becoming a hot water heater expert from now.

What is a hot water heater?

2007-11-12T06:11:00.000-08:00

A hot water heater is a unit with its own energy source that generates and stores hot water.

Water heating is a thermodynamic process using energy source to heat water more than its current temperature. Domestics uses like cooking, cleaning, bathing and space heating are the typical ones that you do usually.

Back in the olden days, hot water is made traditionally using kettles, cauldrons, pots or coppers. These vessels heat were able to heat up water, but the problem is that they do not provide a consistent supply of hot water. Once you have used up the hot water, you have to start heating the water again. While the more-or-less providing constant supply of hot waters were usually known as water heaters, boilers, heater exchangers, calorifiers or geysers depends if it is heating on portable or non-potable water, for domestic uses or industrial uses, their energy sources and the parts of the world they are found.

Introduction to a hot water heater

2007-11-11T07:45:00.000-08:00

So you want to buy a hot water heater? Before you buy a hot water heater, perhaps you should read to find out more about Hot Water Heaters first. This blog should give you a better understand of a Hot Water Heater.

In this blog, we will cover things like

What is a water heater?
Parts of a water heater
How it works?
Types of water heater
How to choose a water heater?
How to replace a water heater?
And more to cover

A blog like this should help you choose your water heater wisely or else you might regret buying the wrong hot water heater.