tankless water heaters pros and cons - two tankless water heaters

Tankless Water Heaters: All The Pros And Cons So You Can Decide!

ByDino Pelle

Tankless water heaters (also called on-demand water heaters) are all the rage these days, so understanding their pros and cons is crucial.

According to manufacturers, the residential and commercial markets for them are growing fast. We’re certainly seeing more requests than ever to install a tankless water heater.

If you’re considering replacing your traditional tank with a tankless water heater, you surely have lots of questions: Do tankless water heaters provide benefits that traditional tanks don’t? Do they last longer? Do they really save on energy costs?

Let’s get some of these questions answered.

What Is A Tankless Water Heater?

You’re probably familiar with a traditional tank water heater. In the simplest terms, it’s just a large container (literally, a tank) that stores and heats your water.

But here’s the problem. It has to continuously heat that water — all day and all night — in order for its limited water supply to be available when needed. And that requires a constant use of energy, much of which is wasted.

Tankless water heaters, on the other hand, work much differently. In fact, there is no need for a storage container which is why it’s called tankless. The water is heated only when you demand it.

Here are the 6 steps in how a tankless water heater works:

  1. A hot water tap is turned on
  2. Cold water enters the heater (it looks like a control panel)
  3. A sensor detects the water and ignites a gas or electric burner
  4. Water circulates through a heat exchanger
  5. The heat exchanger (which transfers the heat to the water) heats the water to your desired temperature
  6. The water heater automatically shuts down when the tap is turned off turned off

A tankless water heater gives you hot water more quickly and less expensively. With no more need to keep gallons and gallons of water continuously heated in a large storage tank before, during, and after you need it, your water can now be heated only as you need it.

One of the tankless water heaters pros and cons can be seen in its size difference compared to the bulkier tank.
This diagram indicates how water flows through the system in order to heat water on demad.

Overall, the driving force seems to be a combination of three things:

  1. The boom in new-housing construction
  2. A growing focus on being environmentally friendly
  3. The eternal human desire for convenience — “I want all the hot water I can get, and I want it right now!”

Now let’s review the pros and cons.

Pros – The Advantages of a Tankless Water Heater

1. Never Run Out Of Hot Water

This is the single best reason to get a tankless water heater. We all know what it’s like to run out of hot water using a traditional water heater. A common tank holds 40 gallons, which can provide hot water for two showers in an hour. You can see how quickly the hot water in your tank can be depleted in a larger family.

That never happens with a tankless. In fact, when correctly sized and properly installed, everyone in your home will get their own limitless supply of hot water. That means you’ll be able to take a luxurious hot bath, run your dishwasher, wash the dog, and use the laundry — all at the same time — without condemning anyone to a cold shower.

2. Use Less Space

Generally, tank-style water heaters are big and bulky because they have to hold and heat a lot of water. And they’re now required to have thicker insulation surrounding them to reduce heat loss because they are only 40-50 percent efficient. This makes them fairly large pieces of equipment.

A tankless water heater is quite small in comparison. It’s most often mounted on your wall (interior or exterior) which gives you far more useable space.

3. Get Hot Water Immediately

A tankless water heater can deliver up to 10 gallons of hot water per minute to all of your appliances, from your shower head to your kitchen faucet. After the cold water is flushed from your system, the hot water gets to you immediately.

4. Prevent Water Damage

If a tankless water heater rusts — and it will take much longer to do so — it won’t leave you with a flooded basement or garage. Nor will it leave you with possibly hundreds or thousands of dollars in water damage to your possessions. If you plan on sticking with that older water heater, here are some maintenance tips you’ll need.

5. Because They Last Longer, They Pay Off

This “pro” is a bit dubious. You probably won’t want to use this as your measuring stick for wanting one of these. Your tankless water heater will outlast your old tank water heater.

On-demand electric water heaters will last at least as long as your old tank. And gas models can last 20 years or more. That’s at least 5-10 years of extra life from your water heater. After the first 12-15 years, depending on your initial investment, you’ll begin to recoup your energy costs.

6. Home Resale Value

Having a tankless water heater in your home won’t increase the value of your home, but it will increase its marketability. Frankly, these on-demand heaters are a growing trend that more and more homeowners want.

tankless water heater pros and cons before and after
They sure do save space!

Cons — Disdvantages of a Tankless Water Heater

1. Your Water Won’t Come Any Faster

This is more a myth than a con: but there’s a false expectation that you will receive instant hot water. You won’t. Think of it this way, no matter how your water is heated, it still has to travel the same distance.

So unless you reduce the distance between the tankless heater and your faucet, or you invest in a water recirculation pump, you won’t get your water any faster.

2. More Expensive Than Traditional Water Heaters

While the cost of a tankless water heater can be downright affordable, the installation will be more expensive. These are complex appliances that need to be professionally installed and configured by a certified plumber.

The work can include rerouting your pipes, creating and properly sealing exhaust vents, and the disposal of the old tank.

3. Inconsistent Temperatures

According to a Consumer Reports survey, a consistent temperature was one of the more common complaints. This is most likely due to improper sizing and installation. Using a professional plumber with tankless water heater experience will eliminate this problem before it has a chance to occur.

4. Use A Water Softener or Higher Maintenance

Finally, here’s the last of our tankless water heater pros and cons. This particular con applies to all styles of water heaters. The “hard water” that most homes use contains minerals that build up over time and cause damage to pipes, faucets, showerheads, and more.

You will need to maintain a tankless once every 12 months. You’ll also need to change the heater’s anode rods every two years. These two factors will reduce the potential savings, especially if you need a plumber to do these for you.

We recommend getting a water softener to prevent this kind of mineral build-up. The savings in maintenance, future repairs, and frustration will be well worth your investment.

We’ve all been there….waiting, waiting, waiting for that water to finally warm up.

Which Tankless Water Heater Is Right For Me: Gas or Electric?

There are different types of tankless water heaters. But most consumers focus on which type of fuel they use, electric or gas. Let’s compare below the differences between electric and gas tankless water heaters.

1. Tankless Electric Water Heaters

Just like it sounds, a tankless electric model uses an electric element to heat the flow of water. Highlights of a tankless electric model include the following:

  • Higher rate of energy efficiency than gas (98-99% vs 80-85%); both are more efficient than traditional tanks (58-60%)
  • Less expensive to purchase and install
  • Little to no maintenance required
  • Can install anywhere (small footprint, no vent needed)
  • Life-span is about 12-15 years (similar to a conventional tank-style water heater)*
  • Electricity costs are higher than gas, but more stable and predictable
  • Does not emit greenhouse gases
  • Many consumers just feel safer using electric devices
  • May require an upgrade to the home’s electrical system
  • Not as powerful; better-suited for 1-2 people, smaller families, or those living in warm-weather climates where water is already warmer
  • The life of any water heater, whether tank or tankless, depends a lot on its proper installation, its quality, and how well it has been maintained.
Here at 1-Tom-Plumber, we love This Old House. Here’s a really informative video on when a tankless electric water heater is a good solution for your home.

2. Tankless Gas Water Heaters

A gas-fueled tankless water heater uses a gas burner to heat the water that comes through it. Here are some highlights to consider:

  • Longer life-span of 20 years or more (higher than both electric tankless or tank-style water heaters
  • More expensive to purchase and install
  • Venting required for installation
  • Often less expensive to operate and maintain (in many regions, gas costs less than electricity, but they are more volatile)
  • Maintenance required, preferably annually
  • Emits greenhouse gases
  • More powerful; can produce hot water more quickly and better suited for larger families or those in cold-weather climates

Final Thoughts

Understanding the pros and cons of tankless water heaters, from electric to gas, will give you more confidence in your purchase decision. If you’re still having trouble making the right decision, contact a trusted plumber with plenty of experience in their installation and maintenance.

Call 1-Tom-Plumber

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need help with your tankless water heater.

1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.

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