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Your Home Depot Tankless Gas Water Heater Guide

Welcome to my comprehensive guide on choosing the best tankless gas water heater from Home Depot. Whether you're looking to upgrade your current water heating system or searching for a more energy-efficient solution, Home Depot offers a wide range of options to suit your needs. In this guide, we'll explore the different types of tankless water heaters available, their features, and the benefits of choosing Home Depot for your water heater needs.

Key Takeaways:

  • Home Depot offers a wide selection of tankless gas water heaters for energy-efficient heating.
  • Choosing the right type of tankless water heater depends on your home's water usage and specific needs.
  • Professional installation by a licensed plumber is highly recommended for safety and compliance with local codes.
  • Tankless gas water heaters have a longer lifespan and provide a larger temperature rise per gallon per minute compared to traditional water heaters.
  • Consider special features such as built-in recirculation pumps and wireless connectivity for added convenience and control.

How to Choose a Tankless Water Heater

When it comes to selecting a tankless water heater for your home, there are a few key factors to consider. Understanding your home's water usage, including gallons per minute (gpm) and the minimum temperature rise required, is essential in choosing the right unit. Additionally, calculating the needed British Thermal Units (BTUs) based on the number of bathrooms and residents in your home can help you make an informed decision.

First, determine your home's water usage by identifying the peak demand scenario. This involves calculating the total gpm needed when multiple appliances are running simultaneously. For example, if you often run a shower, dishwasher, and washing machine simultaneously, you will need a tankless water heater that can provide sufficient hot water at that combined flow rate.

Next, take into account the minimum temperature rise required to reach the desired hot water temperature. This is the difference between the incoming cold water temperature and the desired hot water temperature. Different regions have varying groundwater temperatures, so it's crucial to determine the temperature rise needed for your location.

Sizing Example:

To illustrate the sizing process, let's consider a scenario where three appliances will be running concurrently: a shower (2 gpm), a dishwasher (1 gpm), and a washing machine (2 gpm). The total gpm needed is 5 gpm. If the desired hot water temperature is 120°F and the incoming cold water temperature is 60°F, the required temperature rise would be 60°F (120°F - 60°F). Based on these calculations, you would need a tankless water heater that can deliver at least 5 gpm with a 60°F temperature rise.

By understanding your home's water usage, calculating the minimum temperature rise, and estimating the needed BTUs, you can confidently choose a tankless water heater that meets your specific requirements. Remember, these factors may vary depending on the size of your household, the number of bathrooms, and your typical hot water usage patterns.

Table: Tankless Water Heater Sizing Guidelines

Number of Bathrooms Residents Estimated GPM Minimum BTUs 1-2 1-2 3-5 120,000-150,000 2-3 3-4 5-7 150,000-180,000 3+ 4+ 7+ 180,000+

This table provides a general guideline for estimating the required GPM and BTUs based on the number of bathrooms and residents in your home. However, it's important to note that additional factors, such as high-flow fixtures or specific hot water usage habits, may require adjustments to these estimations. Consulting with a professional and considering the specific needs of your household is always recommended.

Non-Condensing vs. Condensing Tankless Water Heaters

When choosing a tankless water heater, it's essential to understand the difference between non-condensing and condensing models. Both types offer their own advantages and considerations, so let's take a closer look at each.

Non-Condensing Tankless Water Heaters

Non-condensing tankless water heaters use heat exchangers to heat the water. These models typically require stainless steel flue pipes for venting. The heat exchanger transfers heat from the combustion gases to the water, allowing for efficient operation. However, non-condensing heaters do produce exhaust gases, which require venting through stainless steel pipes. This type of heater is a reliable and cost-effective option for many households.

Condensing Tankless Water Heaters

Condensing tankless water heaters take efficiency to the next level. These models utilize the high-temperature exhaust gases to extract additional heat, increasing their overall efficiency. The condensed water that is produced during the process is drained away, usually through PVC venting pipes. Condensing heaters are known for their outstanding energy efficiency and lower operating costs. However, their initial cost may be higher compared to non-condensing models.

Non-Condensing Tankless Water Heaters Condensing Tankless Water Heaters Use heat exchangers to heat water Utilize high-temperature exhaust gases to extract additional heat Require stainless steel flue pipes for venting Can use PVC venting pipes Lower initial cost Higher initial cost Lower energy efficiency compared to condensing models Higher energy efficiency and lower operating costs

Non-Condensing vs. Condensing Tankless Water Heaters

When choosing between non-condensing and condensing tankless water heaters, consider your specific needs, budget, and energy efficiency requirements. Non-condensing models offer a reliable and cost-effective solution, while condensing models provide superior energy efficiency and lower operating costs in the long run. Consulting with a professional and assessing your household's hot water demands will help you make an informed decision.

Tankless Gas Water Heaters

When it comes to choosing a water heater for your home, tankless gas water heaters are a popular and efficient option. These innovative appliances use a gas burner to quickly heat the water as it flows through the system, providing a continuous supply of hot water whenever you need it. One of the key advantages of tankless gas water heaters is their longer lifespan compared to traditional water heaters. With proper maintenance and care, these units can last up to 20 years or more, providing you with reliable hot water for many years to come.

Another benefit of tankless gas water heaters is their ability to deliver a larger temperature rise per gallon per minute (gpm) compared to other types of water heaters. This means that even in colder climates or during peak demand, you can still enjoy hot water without any significant drop in temperature. Additionally, gas-powered units tend to have lower energy costs compared to electric models, making them a cost-effective option for homeowners looking to save on their utility bills.

To give you a better understanding of the advantages of tankless gas water heaters, take a look at the table below comparing them to traditional water heaters:

Tankless Gas Water Heaters Traditional Water Heaters Lifespan Up to 20+ years Average of 10-15 years Temperature Rise Larger temperature rise per gpm Limited temperature rise per gpm Energy Cost Lower energy cost Higher energy cost Space Compact and space-saving design Requires more space for storage tank

As you can see, tankless gas water heaters offer significant advantages in terms of lifespan, temperature rise, energy cost, and space-saving design. Before making a decision, it's important to consider your home's specific needs and consult with a professional plumber to ensure proper installation and sizing. With the right tankless gas water heater, you can enjoy the convenience and efficiency of hot water on-demand, while also reducing your energy consumption and saving money in the long run.

Tankless Electric Water Heaters

When it comes to choosing a water heater, tankless electric models are a popular option. These water heaters utilize an electric element to heat the water, providing a convenient and efficient solution for your home. While they have a comparable lifespan to traditional water heaters, tankless electric water heaters offer several advantages, including lower upfront costs.

One of the key benefits of tankless electric water heaters is their cost-effectiveness. These units are often more affordable to purchase and install compared to their gas counterparts. Additionally, electric water heaters do not require a gas line, making them a suitable choice for homes without access to natural gas. This eliminates the need for a gas line upgrade, further reducing installation expenses.

Despite their lower upfront costs, tankless electric water heaters still provide efficient and reliable hot water on demand. They are designed to heat water quickly and efficiently, ensuring a constant supply of hot water whenever needed. With their compact size, tankless electric models are also space-saving, making them an excellent choice for smaller homes or areas with limited installation space.

Advantages of Tankless Electric Water Heaters Disadvantages of Tankless Electric Water Heaters

  • Lower upfront costs
  • No gas line required
  • Compact size
  • Efficient hot water on demand
  • Potential electrical system upgrade
  • Limited hot water flow rate
  • May not be suitable for large households
  • Dependent on electricity supply

While tankless electric water heaters have numerous advantages, there are a few considerations to keep in mind. Depending on your home's electrical system, you may need to upgrade it to accommodate the increased power requirements of the electric water heater. It is recommended to consult with a licensed electrician to ensure the electrical system is compatible.

Additionally, tankless electric water heaters may have a lower hot water flow rate compared to gas models. This means that simultaneous use of multiple hot water outlets may cause a decrease in water pressure. It's important to consider your household's hot water needs and choose a model that can meet your requirements.

Overall, tankless electric water heaters are an excellent choice for homeowners looking for a cost-effective and efficient hot water solution. With their compact size, lower upfront costs, and reliable performance, they offer a convenient alternative to traditional water heaters. Consider your specific needs and consult with a professional to determine if a tankless electric water heater is the right choice for your home.

Point-of-Use Tankless Water Heaters

Point-of-use tankless water heaters are a practical solution for providing hot water to specific areas or appliances within your home. These compact devices are designed to be installed near the point of use, eliminating the need for long pipe runs and reducing the time it takes for hot water to reach the desired location. With their small size, point-of-use tankless water heaters can easily fit under sinks or in tight spaces, making them an ideal choice for kitchens, bathrooms, or laundry rooms.

One of the main advantages of point-of-use tankless water heaters is their ability to act as dedicated-use devices. This means that they provide hot water exclusively to a single appliance or area, ensuring a constant and reliable supply of hot water whenever it is needed. Whether you want instant hot water for washing dishes, taking a shower, or doing laundry, a point-of-use tankless water heater can efficiently meet your demands.

Point-of-use tankless water heaters also serve as an efficient supplement to a traditional water heater. By installing these devices in areas where hot water demand is high or frequent, you can alleviate the strain on your main water heating system. This not only improves the overall performance of your water heating system but also helps to reduce energy consumption and lower utility costs.

Benefits of Point-of-Use Tankless Water Heaters:

  • Instant hot water at the point of use
  • Compact size allows for easy installation in tight spaces
  • Dedicated-use devices ensure a constant supply of hot water
  • Efficiently supplements a traditional water heater
  • Reduces energy consumption and lowers utility costs

Point-of-Use Tankless Water Heaters Traditional Water Heaters Provides instant hot water at the point of use May require a wait time for hot water to reach the faucet or appliance Energy-efficient operation May have standby heat loss Compact size for easy installation Requires a larger space for installation Can be installed closer to the point of use, minimizing heat loss in the pipes Heat loss can occur in long pipe runs

Overall, point-of-use tankless water heaters offer a convenient and energy-efficient solution for delivering hot water precisely where you need it. Whether you want to improve the performance of a specific appliance or minimize energy waste in your home, these dedicated-use devices are a reliable and cost-effective option to consider.

point-of-use tankless water heater

Special Features

When it comes to tankless water heaters, there are several special features that you can consider. These features can enhance the performance and convenience of your water heater, making it even more efficient and user-friendly. Let's take a closer look at some of these special features:

Built-in Recirculation Pumps

One of the notable features available in some tankless water heaters is a built-in recirculation pump. This pump helps to circulate cold water and maintain hot water at all times. With the help of timers or sensors, you can set the recirculation pump to ensure hot water is readily available whenever you need it, reducing the waiting time for hot water and eliminating water wastage.

Wireless Connectivity

Another exciting feature found in certain tankless water heaters is wireless connectivity. This feature allows you to control your water heater through a smartphone or a smart speaker. With wireless connectivity, you can easily adjust the temperature, schedule heating cycles, and monitor energy usage from the convenience of your phone or home automation system.

Wi-Fi Connectivity

In addition to wireless connectivity, some tankless water heaters offer Wi-Fi connectivity. This advanced feature enables you to connect your water heater to your home Wi-Fi network, providing even greater control and access to your water heating system. With Wi-Fi connectivity, you can monitor energy consumption, troubleshoot issues remotely, and receive notifications and alerts on your smartphone.

Table: Comparison of Tankless Water Heater Features

Feature Description Built-in Recirculation Pumps Helps circulate cold water, ensuring hot water is readily available Wireless Connectivity Control your water heater through a smartphone or smart speaker Wi-Fi Connectivity Connect your water heater to your home Wi-Fi network for remote control

These special features can add convenience, efficiency, and control to your tankless water heating system. Consider your specific needs and preferences to determine which features would be most beneficial for you. Whether it's the built-in recirculation pump, wireless connectivity, or Wi-Fi connectivity, these features can enhance your overall water heating experience.

Before Installing a Tankless Gas Water Heater

When it comes to installing a tankless gas water heater, it's crucial to prioritize safety and compliance with local codes. This is why it's highly recommended to hire a licensed professional plumber who is well-versed in the specific requirements and regulations of your area. A professional plumber will ensure that the installation is done correctly and in accordance with all necessary guidelines.

Before embarking on the installation process, it's important to gather the right tools for the job. Some essential tools you may need include a pipe wrench, drill/driver, and keyhole saw. Having these tools readily available will help facilitate a smooth and efficient installation process.

Installing a tankless gas water heater involves intricate technical work, including connecting the gas line and ensuring proper ventilation. It's paramount to have a professional handle these tasks to prevent potential hazards such as gas leaks or improper combustion. By hiring a licensed professional, you can have peace of mind knowing that the installation will be done safely and up to code.

Overall, the installation of a tankless gas water heater should be treated with the utmost care and professionalism. By hiring a licensed professional plumber, you can ensure that the installation process is carried out efficiently and in compliance with local codes, ultimately providing you with a safe and reliable water heating system.

Upgrade Your Gas Line

When installing a tankless gas water heater, it is important to upgrade your gas line to accommodate the increased demand for fuel. Unlike storage water heaters, tankless gas water heaters require a larger gas pipe to ensure an adequate flow of gas. This upgrade should be performed by a licensed contractor who is knowledgeable about safety standards and regulations.

Adequate combustion air is essential for the proper functioning of a tankless gas water heater. Make sure there is enough ventilation and fresh air supply in the installation area to allow for efficient combustion. This will help prevent any potential issues related to carbon monoxide buildup or poor performance of the water heater.

Proper venting is another crucial aspect of the installation process. Tankless gas water heaters require proper venting to remove combustion byproducts and ensure the safe operation of the unit. The venting system should be designed and installed according to the manufacturer's guidelines and local building codes.

A Comparison of Gas Line Requirements

Storage Water Heaters Tankless Gas Water Heaters Smaller gas pipe Larger gas pipe Lower gas flow demand Higher gas flow demand Adequate for average households Ideal for large households

Upgrading your gas line for a tankless gas water heater is essential to ensure the safe and efficient operation of the unit. By consulting with a licensed professional and following the manufacturer's guidelines, you can enjoy the benefits of a reliable and energy-efficient water heating system for your home.

Remove the Old Water Heater

Before installing your new tankless gas water heater, it is essential to properly remove the old water heater. This process requires careful steps to ensure a safe and efficient installation. Here's a step-by-step guide to help you remove your old water heater:

  1. Shut off the water supply: Locate the shut-off valves connected to the water heater and turn them off. This will prevent any water from flowing into the tank during the removal process.
  2. Turn off the gas supply: If your old water heater is a gas-powered unit, locate the gas shut-off valve and turn it off. This will ensure that there are no gas leaks during the removal.
  3. Drain the tank: Place a bucket or a drain pan under the drain valve of the water heater and open it to release any remaining water. This will prevent any water from spilling and causing damage during the removal.
  4. Disconnect the water lines: Use a wrench to disconnect the water lines connected to the water heater. Be careful as there may still be some water left in the lines, so have a towel or bucket handy to catch any residual water.
  5. Disconnect the gas line (if applicable): If your old water heater is gas-powered, use a wrench to disconnect the gas line. Again, be cautious as there may still be some gas in the line, so follow proper safety procedures.

Once you have completed these steps, you can safely remove the old water heater from its location. Properly disposing of the old unit is important, so check with your local waste management facility for guidelines on how to dispose of it responsibly.

Table: Summary of Steps to Remove the Old Water Heater

Step Description 1 Shut off the water supply 2 Turn off the gas supply (if applicable) 3 Drain the tank 4 Disconnect the water lines 5 Disconnect the gas line (if applicable)

Following these steps will ensure a smooth transition from your old water heater to the new tankless gas water heater. Remember to always prioritize safety and consult a professional if you are unsure about any aspect of the removal process.

Mounting the Water Heater

When installing a tankless gas water heater, proper mounting is crucial to ensure safety and optimal performance. The tankless water heater should be securely mounted using a secure mounting box. This provides stability and prevents any potential movement or accidents.

A direct-vent installation is necessary for venting the tankless water heater. This involves venting the unit through the rim joist using appropriate venting pipes. Following the manufacturer's instructions is essential to ensure proper installation and adherence to safety guidelines.

By properly mounting the tankless water heater and venting it through the rim joist, you can ensure a secure and efficient installation. This will allow you to enjoy the benefits of a reliable and energy-efficient water heating system.

Steps for Mounting a Tankless Water Heater Tools Required 1. Select a suitable location for the water heater. - Stud finder 2. Build a secure mounting box using lumber and plywood. - Circular saw 3. Attach the mounting box to the wall or floor using screws. - Drill/driver 4. Place the tankless water heater inside the mounting box and secure it with brackets or straps. - Pipe wrench 5. Vent the unit through the rim joist using appropriate venting pipes. - Keyhole saw 6. Follow the manufacturer's instructions for proper venting and installation. - Level

Install the Gas Line

When installing a tankless gas water heater, proper gas line installation is crucial to ensure safety and efficient operation. Here are the key steps to follow:

  1. Measure and plan: Before starting the installation, measure the distance from the gas source to the water heater location. Take note of any obstacles or potential challenges along the way.
  2. Choose the right materials: For the gas line, threaded black iron pipe is commonly used due to its durability and ability to handle high-pressure gas. Make sure to select the appropriate size of pipe based on the gas flow requirements of the water heater.
  3. Shut off the gas: Prior to any work on the gas line, turn off the gas supply at the main shutoff valve. This ensures a safe working environment.
  4. Install a gas shut-off valve: Install a gas shut-off valve near the water heater to provide a convenient way to stop the gas flow when necessary. This valve should be easily accessible and clearly labeled.
  5. Connect to the new water heater: Once the gas line is properly installed and the shut-off valve is in place, connect the gas line to the water heater according to the manufacturer's instructions. Ensure tight connections and use appropriate sealing materials, such as gas-rated Teflon tape or pipe thread sealant.

Important Safety Considerations

When working with gas lines, it is important to prioritize safety. Here are some essential safety tips:

  • Consult a licensed professional: Gas line installation should always be done by a licensed contractor who is knowledgeable about local codes and regulations.
  • Perform a pressure test: After connecting the gas line, it is crucial to perform a pressure test to identify any potential leaks. This test involves pressurizing the gas line and checking for any pressure drop over a specific period of time.
  • Properly ventilate the area: Adequate ventilation is essential to ensure the safe operation of the water heater. Follow manufacturer guidelines for venting requirements and ensure that the area is well-ventilated.

By following these steps and safety considerations, you can confidently install the gas line for your tankless water heater, ensuring a reliable and efficient water heating system in your home.

Install New Water Lines

When installing a tankless gas water heater, it is essential to connect the water supply lines properly. This involves installing new water lines and ensuring a secure and efficient connection. One common method is using copper piping, which is durable and resistant to corrosion. Soldering copper pipes provides a strong joint that prevents leaks and ensures a steady water supply.

Before soldering the copper pipes, it is important to clean and deburr them to remove any dirt or rough edges. This ensures a smooth surface for the solder to adhere to. Once the pipes are prepared, they can be soldered together using a propane torch and soldering flux. This process creates a watertight seal that prevents leaks.

It is also crucial to incorporate necessary fittings and valves into the water line installation. A check valve, for example, prevents water from flowing backward into the system and maintains proper water pressure. Bell hangers can be used to securely fasten the copper pipes, ensuring stability and preventing future issues.

Table: Comparison of Water Supply Line Materials

Material Advantages Disadvantages Copper Durable, corrosion-resistant Higher cost, requires soldering Flexible Supply Lines Easy to install, adjustable length May have limited lifespan Black Pipe Durable, suitable for high-pressure systems Requires threading and sealing

Based on your specific needs and preferences, you can choose the most appropriate water supply line material for your tankless water heater installation. Consider factors such as durability, cost, ease of installation, and compatibility with your existing plumbing system.

Install the Pressure Relief Valve

Ensuring the safety of your tankless gas water heater installation is of utmost importance. One critical component that must be installed is the pressure relief valve. This valve is designed to release excess pressure in the system, preventing water overheating and potential damage to the heater. Installing the pressure relief valve correctly is crucial for the proper functioning and longevity of your water heater.

Before installing the pressure relief valve, it is essential to perform a thorough check of the water supply. Inspect all connections and pipes for any signs of leaks or damage. This will ensure that the water heater operates efficiently and prevent any potential issues down the line. If you notice any leaks, it is important to address them before proceeding with the installation.

Once you have confirmed that the water supply is in good condition, proceed with installing the pressure relief valve. Follow the manufacturer's instructions carefully to ensure proper installation. The valve should be securely attached to the water heater, with all connections tightened appropriately. After installation, it is essential to test the valve and check for any leaks. This will guarantee that the pressure relief valve is functioning correctly and providing the necessary safety measures for your tankless gas water heater.

Steps for Installing the Pressure Relief Valve 1. Check the water supply for any leaks or damage. 2. Follow the manufacturer's instructions for pressure relief valve installation. 3. Ensure a secure attachment of the valve to the water heater. 4. Tighten all connections properly. 5. Test the pressure relief valve for proper functioning. 6. Check for any leaks after installation.

By following these installation steps and conducting a thorough check, you can ensure that your tankless gas water heater operates safely and efficiently. Take the time to install the pressure relief valve correctly and perform all necessary tests to avoid any potential safety hazards. With a properly installed pressure relief valve, you can enjoy the convenience and reliability of your tankless gas water heater for years to come.


In conclusion, when it comes to finding the perfect tankless gas water he

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