Pros and Cons of Tankless Water Heaters

If you browse your local home improvement store you’ll find various water heater models, including the tankless type. While tankless water heaters have enjoyed popularity outside of the United States for quite a while, they’ve only started to gain traction in the US in the last few decades. If you’re trying to decide whether a tankless water heater is right for you, consider these pros and cons.


Tankless water heaters have many benefits besides the fact that they lack tanks, including the following.

Efficient Energy

In general, tankless water heaters are more energy efficient than storage tank models. Since a tankless water heater doesn’t turn on until you use hot water, it doesn’t waste energy to heat standing water – like a tank water heater does.

If your family uses 41 gallons or less of water per day, a tankless water heater will be between 24 to 34 percent more energy efficient, according to the US Department of Energy. If you use more, you’re looking at an 8 to 16 percent energy savings.

Longer Lifespan

The average tankless water heater has a lifespan of 20 years, whereas a tank water heater will usually need to be replaced after 10 years. They also usually come with longer warranties – often 15 years – than their storage tank counterparts, which are usually around 6 years.

Smaller Size

While storage tank water heaters take up quite a bit of real estate, tankless units have much lower space requirements. In fact, they hang right on the wall, so they’re more or less out of the way. Depending on how much room you have in your utility area, this could be a big selling point.

Unlimited Hot Water

Since tankless water heaters instantly heat water as it travels through the device, you’ll never run out of hot water. The advantage of unlimited hot water negates one of the biggest downsides of storage tank heaters, which is that once the hot water runs out, you might have to wait a while for the tank to heat up again.


While tankless water heaters have many benefits, you should be aware of a few downsides just in case one of them is a deal breaker.

Installation Expenses

One of the drawbacks to tankless water heaters is the increased upfront cost – which can be substantial. The units themselves are usually more expensive than comparable tank heaters, with gas heaters often in the $1000 to $1500 range.

In addition, the installation can be fairly involved – which means expensive. Tankless gas heaters often require a larger gas line than storage tank water heaters, so the installation process probably won’t involve just a quick swap for the installer. There are also different venting requirements, so a vent pipe might need to be installed.

If you’re installing an electric unit, you’ll need to make sure you have the appropriate outlet near the water heater. If not, you’ll need to call an electrician – an additional expense.

Limited Water Flow

While tankless water heaters do deliver an unlimited amount of hot water, their ability to provide hot water to multiple fixtures in the house simultaneously is limited. If your household frequently has a dishwasher, washing machine, and shower going at the same time, there’s a good chance that a single tankless heater won’t do the trick.

However, you can increase your hot water flow with a few options. You can install small heaters at individual showers and other appliances; you can also run two parallel whole-house heaters.

Hard Water Can Destroy Them

One big downside of tankless water heaters is that they’re vulnerable to damage from hard water, which is usually not covered by the warranty. If you have hard water and you don’t already have a water softener, you’ll need to install one.

Whether tankless water heater is right for you depends on your needs. If you’re still wondering which type is best for you, consult a plumbing professional today.

For all of your plumbing needs, contact Cleary Plumbing.