10 Things You Should Know Before Installing a Tankless Water Heater

Considering upgrading to a tankless water heater but unsure of where to start, or wondering how do tankless water heaters work, and whether they’ll save you money? Tankless water heaters, also known as on-demand or instantaneous water heaters, have transformed how we get hot water in our homes. In this comprehensive guide, we will explore everything you need to know before making the switch. We cover understanding how a tankless water heater works, the benefits and drawbacks, and the factors to consider before installation.

Read on to ensure you have all the information you need to choose the right tankless water heater for your home.

Key Considerations for Readers

If you’re considering upgrading your water heater, here are some important points to keep in mind:

  1. Think about the benefits of saving energy and space when selecting a new unit.
  2. Understand that although tankless water heaters may have a higher initial cost, the potential long-term savings and efficiency could make up for it.
  3. Remember that these systems have the capability to provide endless hot water – a desirable feature for larger households or those with high hot water demands.

1. How Do Tankless Water Heaters Work?

Tankless water heaters, also known as on-demand water heaters, have a simple way of operating to provide hot water without using a storage tank. Here’s how they work:

  1. When you turn on a hot water tap, cold water goes into the unit through a pipe.
  2. The heater’s heat exchanger is activated by a flow sensor as soon as it detects water flow.
  3. Depending on the type of tankless water heater:
  • For gas-fired models, a natural gas burner heats the water by burning the gas in a combustion chamber, which then transfers the heat to the water via the heat exchanger.
  • For electric models, an electric element warms the water as it flows over or through the heat exchanger.

As a result, you get piping hot water directly from your faucets or appliances.

Gas vs. Electric Tankless Water Heaters

Gas-fired and electric tankless water heaters have distinct differences in their operation efficiency:

  • Gas-Fired Models: These models are powered by natural gas and usually have higher flow rates. They generate heat by burning gas in a combustion chamber and then transferring that heat to the water through the heat exchanger.
  • Electric Models: These models use electrical resistance heating elements to heat up the water. While they are generally more energy-efficient than gas models, they often have lower flow rates.

Both types of tankless water heaters have their own advantages:

  • Gas models are recommended for larger households because they can handle multiple hot water demands at once.
  • Electric models are suitable for smaller homes or places where it’s difficult or expensive to install a gas line.

Regardless of whether you choose a gas-fired or electric tankless water heater, both options ensure that you always have hot water available when you need it, without the inefficiencies of traditional water tank systems.

2. What Are The Benefits Of A Tankless Water Heater?

Are tankless water heaters gas or electric?Tankless water heaters offer numerous benefits, including superior energy efficiency, space-saving design, extended lifespan, and the convenience of continuous hot water supply.

Key Advantages of Tankless Water Heaters

Here are some reasons why many homeowners are choosing tankless water heaters:

  1. Energy Efficiency: Tankless water heaters provide hot water whenever you need it, eliminating the energy loss that occurs with storage models. This can potentially result in lower utility bills.
  2. Space Saving: With their compact design, tankless water heaters take up less space compared to bulky storage tanks, giving you more room in your home.
  3. Continuous Supply: Say goodbye to running out of hot water in the middle of a shower! Tankless units can deliver a steady stream of hot water without being limited by a storage tank’s capacity.
  4. Longevity: On average, tankless water heaters have a longer lifespan than traditional storage models, which means they may be a more cost-effective choice in the long run.

3. What Are The Drawbacks of a Tankless Water Heater

Despite their advantages, tankless water heaters come with drawbacks such as a higher initial investment cost, limitations on flow rates, and the necessity for professional installation.

  1. Higher Upfront Cost: One of the primary disadvantages of tankless water heaters is their higher initial investment cost. Unlike traditional storage water heaters that are generally more affordable upfront, tankless models often require a larger initial outlay. This cost can be a deterrent for some homeowners, especially those on a tight budget looking for a more cost-effective option.
  • Limited Flow Rate:Tankless water heaters may have limitations on flow rates, particularly in homes with high-demand water usage. While they are efficient at providing hot water on demand, they may struggle to keep up with multiple showers or appliances running simultaneously, leading to a decrease in overall water pressure.
  • Requires Professional Installation: Professional installation is crucial when it comes to tankless water heaters. These units require specific venting and gas lines, and improper installation can lead to performance issues, safety hazards, and even voided warranties.

4. The Energy Efficiency Advantage of Tankless Water Heaters

Tankless water heaters are known for their energy efficiency because they don’t have the same issue as traditional storage water heaters when it comes to wasting energy. Here’s why tankless water heaters are better at saving energy:

Reducing Standby Energy Losses

  • Storage water heaters continuously heat and reheat water to keep it at a constant temperature, which leads to energy being lost as heat escapes from the tank over time.
  • Tankless models only heat water when it’s actually needed, so they don’t waste energy keeping a whole tank of water hot when no one is using it.

Factors Affecting Flow Rates

The flow rates of tankless water heaters can affect how well they work and how much energy they use:

  • Gas units: These usually have higher flow rates than electric ones because gas burners can produce more heat.
  • Electric models: While they’re usually smaller and more compact, they might need upgrades to the electrical system in order to work at their best and might have lower flow rates as well.

Understanding these factors is important for homeowners who are thinking about switching to tankless technology. By only providing hot water when it’s actually needed and by customizing the system to fit the specific needs of a home, tankless water heaters help conserve energy and save money on utility bills.

5. Weighing the Costs: Initial Investment vs. Long-Term Savings with Tankless Water Heaters

Embarking on the journey of installing a tankless water heater can seem daunting, especially when considering the initial cost. It’s important to recognize that while the upfront investment may be higher than traditional storage water heaters, tankless models shine in their potential for long-term savings.

Initial Costs

The initial cost of a tankless water heater is typically greater than that of a conventional storage water heater. This includes not just the purchase price of the unit itself, but also the cost of professional installation which is highly recommended for these types of systems.

Operating and Energy Costs

One key area where tankless water heaters prove to be more economical is in their operating and energy costs. They only heat water as it’s needed, preventing the standby energy losses commonly associated with storage water heaters. This results in lower energy bills over time.

Longevity and Durability

Tankless models also boast superior longevity and durability compared to their traditional counterparts. While a standard water heater may last 10-15 years, tankless varieties can provide hot water reliably for up to 20 years or more with proper maintenance, further extending your return on investment.

So, while the upfront costs are undeniably higher, taking into account these factors helps paint a clearer picture of why many homeowners are making the switch to tankless water heaters.

6. Key Factors in Properly Installing a Tankless Water Heater

how to install a tankless water heaterEnsuring your tankless water heater operates efficiently and safely hinges on proper installation. It’s not just about following the manufacturer’s instructions; there are critical considerations that require expertise and precision:

Hiring a qualified plumbing and heating contractor

This is not an area to cut corners. A seasoned contractor will have the necessary experience to handle the complexities of tankless water heater installation, which can include gas lines, venting, electrical work, and proper water flow. They’ll understand how to assess your home’s infrastructure to ensure it can support the unit’s requirements.

Compliance with local building code requirements

Every locale has its own set of building codes that govern the installation of plumbing and heating systems. These codes are in place to protect homeowners by ensuring safe installation practices are followed. Qualified contractors will be up-to-date on these regulations and can navigate the permit process, making sure your installation adheres to the necessary standards.

It’s clear that skimping on professional installation can lead to underperformance, safety risks, or even costly damages down the line. By investing in skilled professionals and respecting building codes, you lay the foundation for a seamless and secure tankless water heater setup that stands the test of time.

With these factors in mind, let’s examine another crucial aspect: sizing your tankless water heater to meet your specific needs.

7. Determining the Right Size for Your Tankless Water Heater

Selecting the correct size for your tankless water heater is crucial to ensure it meets your hot water needs without wasting energy. Here’s how to make the right choice:

Estimating Hot Water Demands

To estimate your household’s hot water demands, calculate the gallons per minute (GPM) you expect to use during peak times. Consider the number and types of fixtures, like showers and faucets, and appliances, such as dishwashers and washing machines. Each has a typical flow rate:

  • Showers: 1.5-3 GPM
  • Kitchen Faucets: 1.5-2.2 GPM
  • Dishwashers: 1-2.5 GPM
  • Washing Machines: 1.5-3 GPM

Add up the flow rates of each fixture and appliance that might be used simultaneously to get a total GPM requirement.

Point-of-Use Water Heaters

For targeted applications, point-of-use water heaters are an efficient choice. These are smaller units installed directly where hot water is needed, providing quick and localized heating without the wait or loss of unused heated water in transit from a central heater.

Example: Installing a point-of-use heater under a bathroom sink ensures immediate hot water for handwashing or shaving without drawing from the main heater.

By considering these factors, you can choose a tankless water heater with the capacity to meet your peak demand while avoiding overspending on an excessively large unit.

8. Essential Maintenance Practices for Maintaining Energy Efficiency

Regular upkeep of tankless water heaters is crucial to sustain their high energy efficiency. Here are some essential maintenance tasks:

Flushing and Descaling

  • Hard water can lead to mineral deposits accumulating in the heater, reducing its efficiency.
  • Periodic flushing with a vinegar solution can dissolve these deposits.
  • Manufacturers often recommend performing this process annually, though areas with harder water may require more frequent attention.

Cleaning the Heat Exchanger

  • The heat exchanger is vital to the heating process, and any obstruction can impact performance.
  • Careful cleaning ensures unimpeded heat transfer and operational efficiency.
  • Signs of soot or irregular flame patterns may indicate it’s time for a clean.

Maintenance Specifics: Condensing vs. Non-Condensing Models

  • Condensing tankless water heaters, which are more efficient, condense exhaust gases within the unit to reclaim additional heat. This process results in acidic condensate that necessitates specific maintenance:
  • Neutralizing the condensate before disposal to protect plumbing
  • Checking the condensate drain and trap for blockages
  • Non-condensing models expel exhaust gases directly outside and are less complex but still require:
  • Ventilation checks to ensure proper exhaust flow
  • Regular inspection of the combustion air supply

By adhering to these maintenance practices, you help ensure your tankless water heater operates at peak efficiency, providing significant savings on energy bills and prolonging the unit’s lifespan.

9. Pros and Cons of DIY Installation with Manufacturer Consultation

DIY installation of tankless water heaters can be an appealing option for experienced homeowners who are comfortable handling plumbing and electrical tasks. It brings about a sense of accomplishment, and you can also save on installation costs.

However, keep in mind that this is a complex process that requires precision. Missteps during installation can lead to poor performance, higher energy consumption, or even safety risks. Hence, it’s crucial to follow the manufacturer’s instructions to the letter. Most manufacturers provide comprehensive instruction manuals with their products or offer detailed guides online.

The Pros of DIY Installation

One of the most significant advantages of DIY installation is the potential cost savings. Professional installations can be expensive, and doing it yourself could save hundreds of dollars.

The Cons of DIY Installation

Yet, there are risks involved:

  1. Incorrect installation might void the warranty.
  2. There’s a potential risk of damage to your home due to incorrect installation or gas leaks.
  3. You might miss out on professional advice on optimal placement for energy efficiency.

Opting for a Manufacturer Consultation

A good compromise might be a manufacturer consultation. Many manufacturers now offer virtual consultations where they guide homeowners through the installation process.

A DIY approach may seem attractive, but it is essential not to underestimate the technical expertise required for proper tankless water heater installation. If there’s any uncertainty, hiring a professional is always the safest choice.

10. Ensuring Safety and Code Compliance with Your Tankless Water Heater Installation

When installing a tankless water heater, addressing safety issues is paramount to protect both the property and its occupants. Proper venting and gas line requirements are critical considerations:

Proper Venting

Tankless water heaters need adequate venting to expel exhaust gases. Incorrect venting can lead to carbon monoxide buildup, posing a serious health hazard. Ensure that the venting system is designed and installed according to the manufacturer’s specifications.

Gas Line Requirements

If you opt for a gas-fired model, it’s essential to have gas lines that can handle the demand. A qualified professional should size and install new gas lines if current ones are insufficient.

Local building codes and permits play a crucial role in any water heater installation:

Local Building Codes

These regulations are established to ensure safety standards are met. They cover everything from the placement of the unit to the materials used in installation. Familiarize yourself with these codes or hire professionals who are well-versed in them.


Obtaining the necessary permits is often overlooked by homeowners. However, permits are a formal way of ensuring that your installation aligns with local safety standards. Failure to secure permits may result in fines or complications with insurance claims if problems arise.

By prioritizing these safety measures and adhering strictly to local building codes, you create a safe environment while also ensuring your tankless water heater operates efficiently.


Embracing tankless water heaters can be a beneficial shift for many homeowners. With an impressive energy efficiency, these units offer a significant reduction in energy losses compared to their conventional storage counterparts.

Key considerations for tankless water heater adoption include:

  1. Correct installation: Ensuring your tankless water heater is properly installed by a qualified professional is crucial to its optimal performance and safety.
  2. Ongoing maintenance: Regular upkeep, such as flushing and descaling, ensures the longevity of your unit and helps maintain its energy efficiency.
  3. Proper sizing: It’s essential to choose the right size for your specific hot water needs. This involves estimating your household’s hot water demands and possibly considering point-of-use heaters for targeted applications.

With these elements in place, you can confidently reap the benefits of tankless water heaters. Not only do they provide immediate hot water on demand, but their longer lifespan and lower operating costs also contribute to long-term savings.

Remember, while the initial investment might seem high, the potential savings in energy costs make tankless water heaters an attractive option for those seeking a cost-effective and environmentally friendly solution for their hot water needs. Embrace the future of home heating with tankless water heaters!

Frequently Asked Questions

What is a tankless water heater and how does it work?

A tankless water heater is a system that heats water on demand, rather than storing it in a tank. When a hot water tap is turned on, cold water flows through a heating element and quickly heats up, providing instant hot water.

What are the benefits of installing a tankless water heater?

There are many benefits to installing a tankless water heater, including energy efficiency, cost savings, and unlimited hot water supply. It also takes up less space than a traditional water heater and has a longer lifespan.

Do I need to make any changes to my existing plumbing to install a tankless water heater?

In most cases, yes. Tankless water heaters require a different set-up than traditional water heaters, so you may need to make some changes to your plumbing. It’s best to consult with a professional plumber to ensure a proper installation.

Can I install a tankless water heater myself?

While it is possible to install a tankless water heater yourself, it is not recommended unless you have experience and knowledge in plumbing and electrical work. It is best to hire a professional to ensure a safe and proper installation.

How much does a tankless water heater cost?

The cost of a tankless water heater can vary depending on the brand, size, and installation fees. On average, a tankless water heater can cost anywhere from $500 to $2,500. It’s best to get quotes from multiple companies to find the best price for your specific needs.

Are there any maintenance requirements for a tankless water heater?

Yes, tankless water heaters do require some maintenance to ensure they continue to function properly. This can include flushing the system to remove mineral build-up and replacing the heating element every few years. It’s important to follow the manufacturer’s recommended maintenance schedule for your specific model.

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