What You Didn't Know About Tankless Water Heaters

Upgrading to a tankless water heater is a very wise and economical decision any homeowner can make. Not only does a tankless heater provide hot water at a faster rate, but it’s also more efficient and takes up less space. Unlike tank water heaters that take up a lot of room and can weigh hundreds of pounds, the tankless version can be installed on a wall of a home since they can weigh as little as 45lbs. 

Tankless heaters also eliminate the problems that tank heaters have, and that would be the copious amounts of limescale buildup inside the tank. This is a very common and well-known problem that manufacturers install an anode rod inside the tank. This rod helps to attract hard water minerals and acts as a sacrificial piece of metal for the minerals to attack. Limescale buildup can be very aggressive especially if the source water is considered very hard (300ppm). 

With nearly 85% of homes in the United States accessing hard water, it’s safe to assume that water heater tanks all over the country battle with limescale buildup. If anode rods are not replaced regularly, then the minerals in the water will start corroding the walls of the tank. This causes performance issues especially if limescale buildup is present, it may take longer for the system to heat up, which means higher gas and water bills. In addition, scale particles can break off and make their way through the plumbing and eventually clog pipes and fixtures. Limescale buildup in the tank can also cause tanks to make loud noises throughout the day. The popping noise comes from water that is boiling underneath the limescale. Although the noise itself is harmless, if large pieces of limescale are floating in the tank it could cause corrosion within the walls, dislodged and make its way through plumbing, and eventually cause leaks or damage the heating elements inside. 

As great as tankless systems are, people don't talk about some of the downsides. Just because a tankless water heater doesn’t use a large tank, they are STILL susceptible to limescale buildup. The buildup occurs within the walls of the piping inside the heater itself. As water is heated by gas or electricity, any unused water evaporates. If water sits for a while, the heat causes the water to leave behind traces of calcium and magnesium on the walls of the pipes inside the heater. Over time, those minerals accumulate and can eventually clog the heater or water fixtures. A key indicating factor that would dictate a clogged water heater, would be the drop in water pressure during a shower when you’re washing dishes or any time you run the hot water. 

If this is a problem that occurs in your home, you’ll need to remove the aerators from your faucets and shower-heads to remove any trapped buildup. But if that doesn’t help, there’s a chance that there is scale buildup in random places within the plumbing such as elbows or where joints have been used. 

There are several DIY solutions on how to descale a tankless water heater. Kits can be purchased at most hardware stores or online that provide a cleaning solution, hose, and bucket to allow anyone to do this. But if you are not confident in performing this task, you can hire a local plumber to flush out your tank. Keep in mind that this job can take 1-1.5 hours to perform at a cost that ranges from $125-$300. 

To prevent and resolve scale problems, it is highly recommended that a whole house water softener is installed in the home. This could be done before or after upgrading to the tankless water heater. Depending on the layout of the plumbing in the home, some scenarios can allow for both the tankless heater and water softener to be installed right next to each other. But regardless of the location, the water softener needs to be plumbed into the heater to ensure that it is receiving conditioned water. 

A whole house water softener will prevent future scale buildup throughout the pipes, fixtures, and appliances. Furthermore, having a water softener will help descale the entire water system. Eventually, limescale buildup in toilet bowls will soon start to disappear and never come back. While a water softener helps to protect a home’s plumbing and fixtures, the residents can enjoy mineral-free luxurious showers and baths that provide an environment for soap and shampoo to work properly and not leave a residue on skin and hair.  Dishes will no longer have white spots after putting them through the dishwasher, laundry comes out softer and more vibrant. In addition, the days of soap scum and limescale buildup in the bathroom are over.