One of the biggest competitions in the plumbing world is tankless vs. tank water heaters. In fact, those of you shopping for a new water heater may be on the fence about this exact question.

Below, we’ll compare tankless and tank water heaters to help you decide which is best for your situation.

Table of Contents

• Cost Comparison
• Comfort & Performance
• Maintenance & Longevity
• Feature Comparison
• Conclusion

Tankless Water Heater vs. Tank Cost

We get it—money talks, and the first thing you’re probably interested in is the cost of a tankless water heater compared to a storage tank unit.

Upfront Cost

When it comes to the upfront cost of the unit itself, you will typically save money with a conventional gas or electric storage tank unit, which is more straightforward in design and functionality.

Tankless water heaters are built with higher-quality parts and more powerful burners to heat water on demand. These more expensive internal parts drive up the initial cost of going tankless.

Installation Costs

It's typically less expensive to install a tank water heater. This is especially true if you are switching from tank to tankless.

Installing a gas tankless water heater for the first time often requires new venting and extra plumbing. Since storage tank models have their hot and cold water connections on top and tankless units have theirs on the bottom, switching requires additional piping to reach the base of the tankless heater.

Switching to tankless may also require upsizing the natural gas line to fuel the powerful burner adequately.

Some tankless models on the market, like the Noritz EZTR40, have top-mount water connections that can use existing venting and, in some cases, the same gas line. Although these features do not eliminate the upfront and installation cost differences between a tank and tankless water heater, they narrow the gap.

It's a different story with electric tankless water heaters. Although they don't need a gas line, the electricity requirements often exceed what the typical house can handle, going as high as 150 amps.

Long-term/Energy Costs

Long-term costs refer to how much money it takes to fuel the water heaters over their lifetime. In other words, how much are you paying in energy bills based on your water heater efficiency?

Tankless water heaters are more energy efficient than even high-efficiency storage tank water heaters. Although the highest efficiency storage tank units might be comparable to tankless units in the percentage of captured heat energy, that doesn’t tell the whole story.

A storage tank model’s stored water naturally cools when it’s not being used. This causes the burner to fire periodically throughout the day to keep the water at the set temperature, even if no one needs heated water. This mismatch between hot water supply and demand wastes energy and money.

Tankless water heaters, on the other hand, fire up and heat water only when needed (e.g., when someone turns on the shower). As a result, hot water supply and demand are matched, and you save energy.

Over many years, these savings add up. People who use large quantities of hot water might find that the energy savings from tankless will eventually pay for the additional upfront and installation costs.

That’s not always the case, though, and some people will never recoup the extra cost. It all comes down to usage and energy costs in your area.

Tankless vs Traditional Water Heater Performance

Cost is important, but ultimately, you get a water heater for hot water. How do tank and tankless stack up when it comes to performance and comfort?

Hot Water Availability

Everyone wants constant, consistent hot water when showering. The same goes for other warm water activities such as hand or dishwashing.

With a storage tank water heater, you always have a limited amount of hot water. If it runs out in the middle of your shower, get ready for a cold surprise. Granted, if you own a properly sized storage tank, the chances of you running out of warm water are slim but still possible.

A tankless water heater heats water on demand, so you always have as much hot water as you need for as long as you want. You still need a properly-sized tankless unit to handle your maximum flow rate and temperature differential, but it’s not as if you can ever completely “run out” of hot water. Tankless units will typically reduce their flow rate before sacrificing heat.

One last important note: tankless water heaters only kick on if at least 0.5 gallons per minute of hot water is called for at the faucet. So you might not have hot water for brushing your teeth unless you open the valve almost all the way. It’s a downside, but it probably won’t be noticeable or critical for most people.

Space Savings/Aesthetics

Water heater size might not matter to many people. After all, we usually place our water heaters in obscure corners of our basements or garages—not exactly prime real estate.

However, if someone has a finished basement or garage, then space and aesthetics can be important. For example, you may prefer a comfy recliner where that six-foot-tall, 60-gallon storage tank water heater is standing.

Tankless water heaters are significantly smaller (no tank) and are wall-mounted, allowing them to fit compactly in virtually any space without becoming an eyesore. They’re not breathtakingly beautiful, but they’re much less noticeable.

Tankless vs Tank Water Heater Longevity

The last important question is how tank and tankless water heaters compare in terms of maintenance and longevity.

Maintenance

Both tank and tankless water heaters require periodic maintenance in the form of descaling to remove mineral deposits. The frequency of this maintenance will depend on water quality in your area and whether you use a water softener.

When it comes to parts and repairs, storage tank water heaters are typically a lost cause when they break and need to be replaced. Swapping out individual parts isn’t generally feasible.

On the other hand, tankless water heaters are usually built using modular construction, meaning each broken part can be individually replaced without having to replace the entire unit. Whether it is financially worthwhile to replace an expensive heat exchanger rather than the whole unit is a different matter.

Overall, maintenance is a toss-up between tank and tankless, with a slight advantage going to tankless due to its modular construction.

Longevity

The very last point to consider is the life expectancy of your water heater. Storage tank water heaters typically last 6-12 years if properly maintained. Tankless water heaters can last 10-15 years if properly maintained.

The advantage here is clear. A tankless water heater can potentially last twice as long as its storage tank counterpart. Under those circumstances, the higher upfront costs of tankless don’t matter because one unit could have the life of two storage tank units. 

Tankless Water Heater vs Tank Feature Comparison

Who Wins?

Although the comparisons above seem to favor tankless water heaters as the winners of our clash, it will ultimately come down to your application.

There are instances where storage tank water heaters, despite their shortcomings, are the better option. As mentioned, some people will not realize enormous energy savings from tankless due to water usage or local utility costs. For them, it might make sense to go with the less-expensive upfront option, especially if they're patient enough to wait their turn for hot water or have a small family that won't use as much.

Ultimately, speak with your plumber to determine the best option. He or she will know whether tank or tankless will win the "clash" in your home.

 

 

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