Tankless Water Heater Pros and Cons

Choosing the right water heater for your home isn’t just about comfort; it’s also about efficiency and cost-effectiveness. Among the array of options available on the market, one that has been gaining substantial attention is the tankless water heater. Sleek, energy-efficient, and designed for the modern home, these units promise to revolutionize how we heat our water. But are they the right choice for every house? What are the pros and cons of a tankless water heater? 

Below, you’ll be able to get familiar with the tankless water heater, its benefits, drawbacks, and important maintenance. From there, you’ll be halfway to making an informed decision that suits your home and needs. Let’s get to it!

What is a Tankless Water Heater?

Often known as an on-demand or instant water heater, a tankless heater heats water directly without the need for a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit, and a gas burner or an electric element heats the water.

Unlike traditional water heaters, which constantly heat and reheat water in a tank, tankless water heaters only heat water as needed. This approach can result in higher energy efficiency and potentially lower utility bills—making them a popular choice in modern homes. However, like all things, a tankless water heater comes with its own set of pros and cons, which we’ll explore next!

A comparison of traditional and tankless water heaters

The Upside: Pros of Tankless Water Heaters

As you consider whether a tankless water heater is right for your home, it’s essential to explore the many advantages these modern units offer.

Energy Efficiency

First and foremost, tankless water heaters are loved for their energy efficiency. By heating water on demand rather than maintaining a tank full of hot water around the clock, these units can be 24%–34% more energy-efficient than traditional models for homes that use 41 gallons or less of hot water daily. For homes that use a lot of hot water—around 86 gallons per day—tankless water heaters can still be 8%–14% more energy-efficient. This improved efficiency can translate to significant savings on your monthly energy bills.

Space-Saving Design

Their compact, sleek design is another appealing feature of tankless water heaters. Traditional water heaters require a significant amount of space for the tank, but tankless models can be mounted on a wall, freeing up valuable floor space in your home. This makes them an excellent choice for smaller homes or apartments where space is at a premium.

Unlimited Hot Water Supply

Have you ever been the last one to shower in the morning, only to find there’s no hot water left? With a tankless water heater, this problem is a thing of the past. As long as you stay within the unit’s flow rate, you can enjoy an endless supply of hot water.


Lastly, tankless water heaters are built to last. While traditional tank units usually need to be replaced every 10 to 15 years, tankless models can often last more than 20 years with proper maintenance. This longer lifespan can offset the higher initial costs associated with purchasing and installing a tankless water heater.


The Downside: Cons of Tankless Water Heaters

Despite the many benefits of tankless water heaters, they are not without their drawbacks. It’s important to consider these potential cons when making your decision.

High Upfront Costs

The initial cost is often the most significant barrier for many homeowners. Tankless water heaters can be considerably more expensive to purchase and install compared to traditional tank models. On average, a tankless water heater ranges from $1,000 to $3,000, excluding installation costs. Installation can add another $1,500 to $2,000 to the total cost, depending on the complexity of the installation and your geographical location.

Limited Output

While tankless water heaters provide an endless supply of hot water, they do have a limit on how much they can produce at one time, known as the flow rate. If multiple appliances or showers are running simultaneously, the water heater may not be able to keep up. This could mean a lukewarm shower if the washing machine is running at the same time.

Retrofitting Challenges

Replacing a traditional water heater with a tankless model might require significant modifications to your home’s plumbing and electrical systems. This retrofitting can add to the overall cost and complexity of the installation process.

Inconsistent Temperatures

Sometimes, tankless water heaters can deliver hot water at inconsistent temperatures, particularly if the demand for hot water is sporadic. This phenomenon, known as a “cold water sandwich,” can lead to sudden bursts of cold water during your shower.

While these drawbacks might seem significant, remember that many of them, such as the upfront cost and retrofitting challenges, are one-time issues. On the flip side, the potential energy savings and longevity of tankless water heaters can offset these initial costs over time, making them a worthwhile investment for many homeowners.

Maintenance for tankless water heaters 

Tankless Water Heater Maintenance Recommendations

Proper maintenance is key to ensuring the longevity and efficiency of your tankless water heater. Regular self-checks are crucial, helping to spot any signs of leaks, damage, or wear and tear before they escalate into major repairs.

System flushing is a common maintenance task that removes mineral buildup, which can affect your heater’s performance. Depending on the hardness of your water, you might need to flush your system every six months to a year.

Additionally, your tankless water heater likely has an air filter that blocks debris from entering the unit. Periodic cleaning of this filter is necessary to maintain its efficiency. Check your model’s user manual for guidance on how often to clean the filter. 

If your heater uses gas, remember to inspect the ventilation system periodically. Look for blockages or damage that could impair the heater’s performance or pose a carbon monoxide hazard.

Lastly, arrange for professional servicing of your tankless water heater on an annual basis. A thorough professional inspection can detect and address issues that might go unnoticed in routine checks.

When to Call a Professional

Regular self-maintenance is crucial, but sometimes professionals are necessary. A sudden drop in your water heater’s efficiency signals a problem. This could mean a faulty heating element or mineral buildup. Leaks from your unit also require professional attention. They might indicate connection issues or a heat exchanger crack.

Modern tankless water heaters have digital displays, showing error codes when something goes wrong. If you see these codes, it’s a sign to call for help! Some maintenance tasks can be done at home, like cleaning the air filter or flushing the system. However, a professional should service your unit annually. They perform comprehensive checks and clean essential components, ensuring your unit continues running efficiently.

Regular professional maintenance optimizes your water heater’s operation and prolongs its life. Knowing when to call a professional can prevent major issues and ultimately help you avoid major issues, saving you money and time.


Choosing a water heater for your home involves balancing several factors, and a tankless water heater brings its unique set of pros and cons to the table. The energy efficiency, space-saving design, and longevity of these units are compelling advantages. However, the higher upfront costs, the potential for limited output, and the need for occasional professional maintenance are aspects to consider.


Every household’s needs are different, and what works best for one might not be the same for another. The key lies in understanding your home’s hot water usage, budget, and space constraints. Weigh these against the benefits and drawbacks of tankless water heaters. By doing so, you’ll be well-equipped to decide if going tankless is the right move for your home.

For a comprehensive inspection of your entire home, HVAC, or plumbing systems, reach out to Infinity Inspection Services in Miami, FL, and surrounding areas today!