Lime Scale…. The Energy Thief
From the smallest homes and business to the very largest, everyone invests a substantial amount of money into heating water. The problem is lime scale buildup on the surface of water heaters, which significantly reduces heat transfer. This lime scale reduces heat transfer, decreases fuel efficiency, and will ultimately lead to equipment failure.
Water naturally contains dissolved minerals such as calcium carbonate, lime, silica, iron, and phosphate to name a few. These trace elements are essential to human health, not so much for your water heater though. With heat the minerals are able to precipitate out and build up on the surfaces.
On day one of a tank type water heater you looking at your greatest efficiency, sometimes as high as 80%. This is reduced quickly as the lime and other particles cling together and bake themselves into a hard crust. This scale builds up on the walls and blocks the heat transfer proportionally as much. With the additional heat not being transferred into the water the steel becomes brittle and can crack quite easily.
Solutions For Lime Scaling
For a tankless water heater it is essential that you have the system flushed once a year with a de scaling solution (vinegar). This maintains the tankless heat exchanger and ensure a consistent efficiency rate. As for your conventional tank water heater, flushing is more difficult but can be done. For the most part they are designed as disposable units that are simply just replaced if broken.