Who Wins the Tank vs Tankless Water Heaters Contest?

Hot water from a tank or tankless water heater

Everyone loves hot water, but what type of water heater is the best? Most folks still have conventional tanks, but we also see a lot of people around Atlanta opting for tankless water heaters. Presumably, these folks have good reasons for choosing tankless. But what are they?

Let's put it another way. If conventional water heaters and tankless were to, well… face-off, who would win? Is there a clear victor in the tank vs tankless water heater contest?

There's only one way to find out! Let's run these two different types of water heaters through a five-round competition in all the categories that matter.

Round 1: Hot water availability

Conventional water heaters hold a large volume of water inside a tank. Whether powered by natural gas or electricity, heating equipment inside the water heater works to keep the water in the tank hot. Typically, "hot" means a temperature between 120 and 140 degrees.

If you use a lot of hot water at once, it's possible to consume all the hot water inside the tank before the water heater can finish heating any more water. You may have had this happen when three people have taken showers in direct succession while the washing machine was on.

In other words, you can run out of hot water. With conventional water heaters, it's a fact of life.

Tankless water heaters, on the other hand, provide endless hot water. As long as the water heater is functioning properly, it will heat as much water as you need.

That's because tankless units heat water on demand. You turn the hot water tap, and the water heater turns on to heat water as it flows through the unit. It's not constantly running to keep a finite amount of water (like whatever is inside a water tank) hot.

If the availability of hot water is your primary concern when choosing a water heater, you can't beat tankless units. Sure, you could always get a bigger tanked water heater, but the possibility of running out of hot water remains.

Winner: Tankless

Round 2: Energy efficiency

Here's where we need to differentiate between two types of tanked water heaters: conventional and heat pump.

Conventional water heaters are the least efficient of all the different types. Heat pump water heaters, on the other hand, look kind of like conventional water heaters (they have a tank, for instance); however, they're extremely efficient because of the way they heat water.

As their name implies, heat pump water heaters contain - wait for it - a heat pump that removes heat from the ambient environment and transfers it to the water inside the tank. Because of this design, they're vastly superior in efficiency when compared to conventional water heater tanks.

Now let's look at tankless water heaters. They're more efficient than conventional water heaters because they're not constantly firing (natural gas) or powering heating elements (conventional electric) in an effort to keep a large volume of water at 120+ degrees. They only fire on demand, so they're significantly more efficient than conventional tanks.

But they're not more efficient than heat pump water heater tanks.

All of that being said, we'd rank the energy efficiency of these three types of water heaters as follows:

  • Most efficient: Heat pump water heater (tank)
  • More efficient: Tankless water heater
  • Less efficient: Conventional water heater (tank)

Tanked units can only win this round if we're talking about heat pump water heaters. Therefore, we'll call it a tie

Winners: Tank and tankless (tie)

Round 3: Installation costs

This one's easier to judge. Standard water heater tanks are way less expensive to install compared to tankless units. The cost of installation is actually the biggest barrier for many people who would otherwise want a tankless water heater.

How much more expensive is it? Generally speaking, a tankless water heater installation costs 3 to 4 times more than installing a conventional water heater.

If you're looking for the most affordable installation for your new water heater, you probably won't get a tankless unit.

Winner: Tank

Round 4: Lifespan

Whether you choose a standard tank or a tankless unit, you're looking at roughly the same lifespan: 10 to 15 years.

Many factors impact how long your water heater lasts, and they range from the quality of the initial installation to the characteristics of the surrounding environment. Water heaters located inside damp crawlspaces, for example, may be more likely to rust or become havens for insects. Either of these situations could reduce the lifespan of the water heater.

On the other hand, regular maintenance - especially for tankless water heaters - can increase the lifespan of the equipment. We'll discuss maintenance in more depth during the next round.

Winners: Tank and tankless (tie)

Round 5: Maintenance

If all you've ever had is a conventional water heater tank, you've probably never needed much water heater maintenance. That's because standard water heaters don't have many issues!

Sure, some parts can leak; elements on electric tanks can go bad; burners on gas units can rust. Still, most of these issues are minor, and many tank water heaters never even have problems until they fail completely and require replacement.

With tankless water heaters, well… more can go wrong.

The most common issue is mineral buildup inside the unit, and the only way to combat the problem is to regularly flush the equipment using special chemicals. This should be done every two years for most units, but some manufacturers suggest more frequent flushing.

Tankless water heaters also have inducer fan motors, so they burn fuel like a furnace. As a result, they get dirty the same way a furnace gets dirty and may need to be cleaned. We've even seen issues with insects, lint, and other refuse getting inside tankless units' combustion air pipes and causing performance problems.

At PV, we actually have a service plan just for clients with tankless water heaters. We come by once per year and perform a comprehensive inspection of the unit, flush it out to prevent mineral buildup, and verify combustion safety.

Winner: Tank

Bonus Round: Space

So far, it looks like tanks are one point ahead of tankless water heaters. But it's still really close, so why not give our tankless contenders one more shot at glory? Let's consider which unit takes up the least amount of space.

There's actually a pretty clear winner here. Tank water heaters, regardless of other characteristics, always require some floor space. Tankless units, on the other hand, typically mount to the wall. They require no floor space at all!

If you need a spot for your drum set in the basement, switching to a tankless water heater may give you the extra 10 or 15 square feet you need.

Tankless water heaters are space savers, plain and simple. Besides providing endless hot water, it's probably their biggest advantage.

Winner: Tankless

Wow! It looks like tank vs tankless water heaters ends in a draw.

By our calculations (and with the bonus round), both tank and tankless water heaters have earned 4 points. The contest has ended in a draw, but that doesn't mean there won't be a clear winner for you.

Ultimately, your choice of water heater depends on your priorities.

If you want endless hot water, tankless is definitely the way to go. But if you're looking to minimize installation costs, a conventional water heater tank is a better choice. Want the most energy-efficient option? A heat pump water heater tank is the answer.

Oh, and if you live in metro Atlanta and need help choosing the best water heater for your home, drop us a line! We'll always take the time to listen to your concerns, examine your existing water heater setup, and help you select the most sensible option for your needs and your budget.