Hot Water Energy Analysis & Worksheet
The purpose of this page is to provide support data and basic information on how a water softener saves on energy consumption when water is heated by various methods, to serve or satisfy a particular need. As the cost of energy escalates, all of us become even more aware of the rising cost of the fuel consumed to perform the necessary water heating requirements. The primary concerns are to conserve on energy and to improve the efficiency of the water heating process.
This information will be of use and of interest to you if you are concerned about the efficiency of a water heating system, or would like to keep better control of the cost of operating a plant or specific process using hot water. You may be involved in the design, operation, maintenance or purchasing of equipment, and need to justify the cost of new or replacement components or a complete system. All water using and heating appliances or systems are affected by the quality of the water being supplied for their use or processing.
Up until the recent past, the need to be concerned about the quality of water we were using was left to someone else. Unless we could visually see a problem, or smell or taste something in the water, we would naturally take it for granted that the quality of the water was very adequate for our use. Some of you knew better and were very aware of the need for water treatment or conditioning. You were aware of the added expenses involved in maintaining and operating equipment when the water caused problems, when the water was not taken care of by water conditioning. We now have some added support data to show that your concerns were right and that you can save energy and operating costs by improving the efficiency of a water heating system. This can be done by using soft water.
The application of a water softener to eliminate the formation of the hardness scale reduces fuel consumption. Tests conducted at the New Mexico State University have shown that gas fired heaters consumed 29.6% more BTU’s and electric heaters consumed 21.7% more BTU’s when operated on hard water than they did when operated on softened water.
The water softening process removes the hardness or scale forming minerals, which are calcium and magnesium and, in some cases, clear water or ferrous iron. These hard minerals react or are affected by heating of the water. When heated these minerals have a tendency to precipitate or fall out of solution and form a hardness scale. You may have seen this scale in plumbing, hot water tanks, on low water cut-offs, heater elements, pumps, or possibly in the water or kettle on the old stove top. The scale looks like, and basically is, limestone which has some substantial insulating properties. The hardness scale formation interferes with the heat exchange process and drastically lowers the fuel efficiency of the water heater.
We can conserve by lowering the temperature of the heated water to the lower limit of the heated water usage. We will also eliminate waste of heated water by fixing leaks and closer monitoring of the hot water or steam system and insulating lines as well as holding tanks.
To improve the efficiency of the water heating process, the elimination or removal of scale forming minerals from the water supply is very important. This is accomplished by a water softener.
The accumulative effect of improving the efficiency of the water heating process is very significant. Checking with the Minnesota State Energy Commission revealed that over 60% of the energy consumed in commercial and institutional buildings is used to heat water.