Hard water is microscopic mineral deposits or sediment such as iron, calcium, limestone, sand and silt. When a coil is used, the deposits restrict the heat transfer as water passes through the coil. When a water tank is used, the deposits act as a barrier or insulator between the heat source and the water which requires more energy to heat the water. Every half inch of sediment on the bottom of the heater will require 60 to 70% more fuel to heat the water. Once the sediment is removed, the water becomes hotter and the showers are longer.
Did you know ... by cleaning your hot water coil or hot water heater on a yearly basis, you will have hotter water and If your water is hotter, you will use less of it, which in return reduces the amount of water you heat. Just think about it, by saving 3 gallons of hot water every day you will save 1100 gallons per year, which in return will reduce the of the amount of oil, gas and electric you use, thereby saving you money.