How To Save On Hot Water Bills. Compare Tankless Water Heater To Storage Heater

It costs a considerable amount of money to heat water for household purposes. For an average US householder the cost of heating water runs to between 20% and 25% of the total energy bill for the home. With the extremely high energy costs experienced towards the latter end of 2005 it has become imperative for home owners to reduce water heating costs. One of the quickest and best ways to do this is to install a tankless water heater for all your hot water needs.

What Is A Tankless Water Heater? ... also called on demand or intantaneous heaters.

Most of us draw hot water from a tank or cistern system (called hot water storage heaters). This tank has an electric heating element in it or alternatively it uses a gas or oil fired heater to heat water which is then stored in a tank. Household water has been heated like this for many years but the trouble is that these systems that store hot water even though they are insulated suffer from real heat loss called "standby losses". These losses account for about 10 to 20% of the hot water heating cost ... it is completely wasted energy.

A tankless water heater is a relatively small heat exchanger ... cold water flows in one end and hot water out the other. If the water flow is turned off the energy source is also turned off so that no hot water is stored. Another word for tankless heaters are instantaneous water heating devices. This is self explanatory ... hot water is instantly available by opening the tap. The water is heated in the heat exchanger using gas, oil or electricity which would be "piped" up the unit. Read the rest of this page then take a look at how to choose a new tankless water heater

The Basics Of Heating Water Is Simple ... Everybody Needs To Understand

In a hot water storage tank heater, energy is required to heat the water in the storage tank and to keep it hot for use on demand. Hot water drawn from the tank is replaced by cold water which mixes with the remains of the hot water remaining in the storage tank. This lowers the average temperature of the contents. The contents are then heated to bring the new lower temperature up to that specified by the automatic cut-off, called a thermostat.

If I use an example ... lets say the storage tank holds 100 gallons of hot water at 80 degrees F and you pull off 10 gallons. Then obviously 10 gallons of cold water will then enter the tank. If this cold water is at 40 degrees F then energy must be supplied to heat the 10 gallons to 80 degrees. The problem with storage tank systems is that the hot water continues to lose heat to the surroundings and the energy source goes on and off to maintain the temperature at 80 degrees even if no water is drawn off the tank.

Hereon lies the single biggest energy saving advantage of a tankless heater. Using the same example if you draw 10 gallons of 40 degrees water and heat this to 80 degrees that is all the energy consumed because no water is stored.

In both storage and tankless heaters, the basic efficiencies of initially heating the water are very similar. This is because the amount of energy required to heat a fixed amount of water is determined by a simple formula as follows ...

Formula For Heating Water In All Systems

Flow rate of water in any units (eg gallons per minute or litres per hour) x a constant number called specific heat x the number of degrees the water must be heated by .... interpreting this in simple terms it means if you double the flow and want to keep the temperature increase the same (eg from 40 to 80 degrees)you must double the energy supplied be it in the form of electricity or gas or any other energy type

This basic formula will be used throughout the site to explain how to save money and how to quantify the savings so that comparisons can be made between different systems and different makes of similar systems since not all is what it often appears to be.

Common Terms used By the Hot Water Heating Industry ... Important

In any industry there is a degree of jargon and the hot water heating industry is no different. I've tried to define the important terms in a simple to understand practical way.

Energy Factor ... every hot water heater no matter whether it is tankless or storage hot water application must be provided with a certified Energy Factor. This factor relates to how efficient a unit is (related to technology used in design of heaters) and can be interpreted as follows ... if the Energy Factor is high then the annual cost of energy (gas, propane, oil or electricity) to run the tankless hot water heater or the storage heater will be lower than it would be for a system with a lower Energy Factor. Energy Factors for Gas tankless water heaters range from 0.64 to 0.82 normally. Now this is a big difference and has an important cost implication. High energy factor corresponds to lower cost.
First Hour Rating ... this number refers to the amount of hot water the heater can supply per hour. If a storage tank system is in use the assumption is that the tank is full of hot water at the start of the first hour.
Heating Energy ... the energy required just to heat the hot water and is calculated as shown above. It is proportional directly to flow arte and how much you want to increase the water temperature by
Standby Energy ... the energy that will be lost based upon a tank full of hot water just standing. Heat will be lost depending and quantity will depend on how well insulated the system's storage tank is. The water will cool down which means more energy is needed to bring the temperature back to that required. The average home in the USA will use a 40 gallons gas fired hot water storage heater. Refer to the GAMA (Gas Appliance Manufacturers Association) guide. These hot water heaters will have Energy Factors ranging from 0.54 to 0.64 (compare tankless water heater information above).
Average Gas Energy Cost ... it is assumed that national US average fuel cost of 1.42 $/therm will be used.
Electricity Energy Cost ... it is assumed that average national cost is $0.1178 per kiloWatt Hour
Hot Water Usage Rate ... this can vary a great deal based upon number in family and time of day. The correct heater should be designed on basis of maximum hot water heating load. In other words what amount of hot water is required at busiest time of day.

The units used by different energy systems are varied and typically are as follows ...

Hot water tankless and storage heaters using oil .... gallons of oil is energy measurement
Tankless and storage heaters using Propane or Natural gas .... therms or BTU's of gas is energy system used
Tankless water heating and storage heaters using electric power .... kiloWatt Hours (kWhr) is energy unit

Compare Storage Tank Heater and Tankless Water Heater

There is no doubt that tankless heaters are evolving and being used more and more especially in new homes. Energy conscious homeowners are making the switch as exisitng storage applications come towards the end of their useful life.

Hot Water System	Tankless Water Heaters	Storage tank hot water systems
Overall energy cost	Lower cost owing to saving the standby losses associated with cistern type applications. Typically tankless units are 30% more efficient than storage units. Endless supply of hot water.	Higher losses ... even well insulated tank systems lose about 20% of the heat stored in the tank. Once the tank has been consumed it takes a long time to reheat the water
Unit size	Much smaller footprint and easier to install making them suitable for many different applications from boats to motor homes	Large compared to tankless hot water heater and need significant piping and storage space.
Installation cost	Small compared to storage tank heater in new structures but higher in replacement situations.	More complex and expensive to install in new structures or homes
Installation space	Compact unit .. saves valuable and costly space taken up by storage tank which can be used as closet for example	Bulky heater and tank system with difficult access normally situated in loft or out of way place
Lifetime	Up to 20 years with 10 year guarantee normally	About 10 to 15 years
Capacity	When large quantities are required simultaneously flow can reduce or temperature of water is lowered. There is a maximum flow constraint but supply is endless	Depends on size of tank capacity. Betetr for for simultaneous high flow use such as 2 showers at same time. Once tank is empty no more hot water for some time.

Some Common Uses For A Tankless Water Heater

Tankless water heaters come in a variety of sizes for different applications, such as a whole-house hot water heater, as a hot water source for a remote bathroom or hot tub, or as a boiler to provide hot water for a home heating system.
Tankless hot water heaters can also be used as a booster for dishwashers, washing machines, and a solar or wood-fired domestic hot water system. You may install an on-demand water heater centrally or at the point of use, depending on the amount of hot water required. For example, you can use a small electric unit as a booster for a remote bathroom or laundry.
Using low-flow shower heads and water-conserving faucets are a good idea with demand water heaters. Demand water heaters cost more than conventional storage tank-type units.
The appeal of on-demand or instantaneous hot water heaters is not only the elimination of the tank standby losses and the resulting lower operating costs, but also the fact that the heater delivers hot water continuously at a higher fuel efficiency.

List Of USA Water Heating Equipment & Products Manufacturers

American Water Heater Company, Apollo Comfort Products, A. O. Smith Water Products Co., Bock Water Heaters Inc. .. makers of oil heaters, Bradford White Corporation, ECR International, Eemax Inc., GAMA, GSW Water Heating Company, Heat Transfer Products Inc., Lochinvar Water Heater Corporation, Madwolf Technologies, Llc (Ron), Maytag, Reliance Water Heater Company, Rheem Mfg. Co., Water Heater Division, Richmond Water Heaters, Ruud Water Heater Division, Sears, Roebuck And Company, State Industries, Inc., U.S. Craftmaster Water Heaters, Vaughn Manufacturing Corp.,