If you live in an area with a hard water supply, it is well known that hard water may shorten the lifespan of the water heater. Not only water heaters are affected – all home appliances that heat up water suffer from scale buildup, and logical solution is installing a water softener, the separate device which descales water and protects your household goods.
There are several types of water softeners on the market, but one category may be considered as conventional – when talking about water softening system, people usually have in mind salt-based ion exchange softener.
First, let’s see what at an ion exchange water softener is.
An Ion exchange water softener is a device that removes undesirable substances (mostly Ca and Mg ions) and replaces them with sodium chloride ions; simply, instead of calcium and magnesium, the salt is fed to the water.
The system consists of a cabinet which houses an ion exchanger. There are two components inside – a container with the little resin beads and the other one with a brine. Water flows through the resin which attracts Ca and Mg ions and releases sodium ions. When resin becomes saturated the regeneration process starts – brine is being flushed, to bath the resin beads and remove captured ions.
All parts fit in the single cabinet or two cabinets (one for the resin and the other for the salt), but don't be confused – manufacturers also offer duplex system, with two exchangers. You could find it under the name "dual-tank water softener".
Dual-tank softener provides a non-stop functioning, including the regeneration cycle. When one exchanger is disconnected from the water supply, because of "recharging" and renewing, the other one jumps into its place to provide full comfort to the user.
If you have decided to buy a water softener, acquire some information in advance. We suggest considering the following.
Grain capacity. The first numbers which will attract your attention are those about grain capacity. You may find 32.000 / 48.000 / 64.000 grain (weight unit) softeners, meaning that device can remove that quantity of scale in one cycle, before regeneration is needed. However, this is not reliable sum because it depends on the variable conditions. Following two features are more important.
Volume of the resin. The usual volume of home softener is 1 or 1.5 or 2 cubic feet.
Efficiency is the most interesting detail you have to look at, according to experts' advice. Search for Softener Efficiency Rating (SER) in technical specification and choose the softener which removes 3,333 to 5,000 grains per pound.
Resin quality. The resin is, actually, plastic, which is better to be harder. The number you are searching for is cross-link percentage. Choose 10% if you can, but 8% is still good.
Service Flow Rate (SFR) in gallons per minute, which is often in 15-20 range, is the amount of softened water that a softener can produce. This data is the maximum available rate, not the real one. If you want to calculate how many SFRs you need for the perfect soft water, take into account water hardness and number of demanding appliances in your home. Softening the water for hot water heater requires resin volume of more than 1 cubic feet and softener SFR of more than 5 gallons per minute. If you have additional appliances, performance requirements rise.
Tip: Don't forget to check your water line diameter.
Device size. If you plan to buy the central softener to attach it to the house installation, measure dimensions of free space, usually in the basement of the house. Smaller devices for one appliance can be installed, for example, in the kitchen below the sink.
Certification. There are two important tags to check in, both available in USA and Canada. The NSF International (National Sanitation Foundation) tests water-treatment products and issues certificate and Water Quality Association delivers WQA Gold Seal.
As any other device, water softeners cannot last forever. It is expected to have them last at least twenty years. The tank and control valve are subject to the warranty, usually ten and five years respectively. You may find less than five years warranty for the control valve, but the manufacturers of the best brands (Pentai, Clack, Autorol...) offer five years.
All features mentioned above can serve as a good basis for comparison before a purchase.
The pros of installing softener are clear – protected appliances, less limescale on taps and dishes, faster water heating, better performance of shampoos and detergents, longer life of a water heater, but are there any cons?
Besides the additional plumbing work and bills for the salt, the maintenance of the softener is also needed. There are dilemmas about health impact – soft water is not recommended for drinking and cooking for the long term and it tastes different. Some recommend separate tap, out of softener influence, for drinking purposes.
To conclude briefly: Scale deposits inside the electric water heater, especially on the heating element, cause overheating, bad performance, higher energy bills... The similar thing is happening inside the tank of gas water heaters, even in tankless water heaters. The softener function is to remove calcium and magnesium from the water in order to prevent the limescale – and it does that job well.