Best Gas Tankless Water Heater Models of 2024: Top Picks & Reviews

Tankless water heaters are becoming a staple in homes for their efficiency and convenience. Unlike a traditional tank water heater that constantly heat and reheat water, a tankless system heats water on demand, providing you with an endless supply of hot water while also saving energy.

Gas tankless water heaters, in particular, offer the benefits of lower operating costs and a smaller carbon footprint since they typically use natural gas or propane, which are cleaner burning fuels compared to electricity from coal-fired plants.

Choosing the best gas tankless water heater for your home involves careful consideration of various factors. You should look at the flow rate, which is measured in gallons per minute (GPM), to ensure it meets your hot water needs.

It’s also important to consider the energy efficiency, expressed as an Energy Factor (EF) or Uniform Energy Factor (UEF) rating; a higher number indicates a more efficient unit. Size and installation requirements are vital, too — you need a place that provides proper ventilation and access to a gas line.

Lastly, ensure to factor in the longevity and warranty of the heater, so you can enjoy a consistent hot water supply for years to come.

With these considerations in mind, you’re well on your way to finding a gas tankless water heater that delivers performance, efficiency, and convenience. The right model will not only provide you with hot water on demand but also help reduce your energy bills and environmental impact, making it a smart choice both practically and financially.

Let’s explore some of the top contenders in the market to help you make an informed decision for your household’s hot water needs.

Why Choose Gas Tankless Water Heaters?

If you’re considering an upgrade to your home’s hot water system, gas tankless water heaters could be a smart move. Unlike traditional tank water heaters with bulky tanks, these sleek models heat water on demand. This means you’ll enjoy endless hot water—no more cold shower surprises when you’re the last one to get ready in the morning.

Energy efficiency is a standout feature. Gas tankless heaters boast higher efficiency ratings because they only heat water as you need it. This eliminates the energy wasted by keeping a tank of water hot 24/7. In fact, according to, tankless water heaters can be 24% to 34% more energy-efficient for homes that use 41 gallons or less of hot water daily.

Here’s a quick comparison:

FeatureGas Tankless HeatersConventional Water Heaters
EfficiencyHigh (only heats on demand)Lower (heats continuously)
Space SavingsCompact sizeLarge, bulky tank
LongevityTypically 20+ yearsAround 10-15 years
Initial CostHigherLower
Long-term SavingsSignificant (due to efficiency)Less potential for savings

Cost-effectiveness is another reason to choose gas tankless heaters. Although the initial price may be higher, they generally have a longer lifespan—often twice as long as their tanked counterparts. This means you’ll save money in the long run on replacement costs, in addition to the savings on your energy bills.

Think about the convenience too. You can tuck these units in small spaces, freeing up room in your basement or closet. Plus, with the ability to provide hot water on demand, your lifestyle receives an upgrade in comfort and convenience.

Overall, transitioning to a gas tankless water heater means embracing efficiency, savings, and a continuous supply of hot water that aligns with your modern living needs.

How We Chose The Top Gas Tankless Water Heater

To select the top gas tankless water heaters, we focused on several key criteria. Your needs were at the forefront, so Energy Efficiency was a top factor; units with high energy factor (EF) ratings were prioritized.

Efficiency is nothing without Performance and Reliability. Heaters with a reputation for consistent output and low maintenance made our list. We honed in on models boasting longevity, responsive customer support, and robust warranties.

The Capacity of the heater is vital to meet your specific hot water demands. Heaters were evaluated on their gallons-per-minute (GPM) rate, ensuring they can handle simultaneous showers or appliances running.

Installation and Usability shouldn’t give you headaches. We chose units that offer straightforward installations and simple operation, with some featuring advanced options for tech-savvy users.

Lastly, we considered Value for Money. Your investment should bring you returns in terms of efficiency, comfort, and service life. Our list includes options offering competitive pricing without compromising on quality.

Energy EfficiencyHigh EF ratings, lower utility bills
PerformanceReliable hot water supply, lasting durability
CapacityAbility to meet simultaneous demand for hot water
InstallationEase of set-up and user-friendly controls
Value for MoneyReasonable prhice tied to performance and features offered

The water heaters that excelled across these criteria made our selection, ensuring you get only the best for your home.

Best Gas Tankless Water Heater Models

Upgrading to a gas tankless water heater ensures you never run out of hot water and can also reduce your energy bills. These efficient units heat water on demand and occupy less space than traditional tank heaters. In this selection, you’ll find the finest models that offer reliability, performance, and innovative features tailored to suit your hot water needs. Enjoy exploring these top contenders!

Rinnai RU160iN

If you’re eyeing a water heater upgrade, the Rinnai RU160iN might just be the smart, high-efficiency solution you need.


  • Provides an endless hot water supply on demand
  • Saves space and energy by heating water only when you need it
  • Delivers strong water pressure with up to 9 GPM flow rate


  • Requires professional installation
  • May need additional adjustments to your plumbing system
  • Controlr Wi-Fi module for remote monitoring is sold separately

Imagine never running out of hot water halfway through a shower again. The Rinnai RU160iN gets rid of that problem for good, offering you endless hot water whenever you need it. Its sleek, space-saving design not only frees up real estate in your home but also goes easy on your energy bills. You’re making a choice for both comfort and the environment.

Installation needs a professional touch, and you might want to prepare for some plumbing updates. This is standard for tankless systems, especially if you’re switching from a storage tank model. Though the initial set-up requires effort, the long-term benefits are clear: non-stop hot water and reduced energy costs.

The absence of in-built Wi-Fi may feel like a drawback, but it’s an easy fix with an added module. The ability to monitor and adjust your hot water heater from afar is a modern convenience that’s worth investing in. You’re setting up your home with a system that’s designed to serve you well into the future, backed by robust warranties.

Rheem RTGH-95DVLN-3

If saving space and energy while getting instant hot water is your priority, this Rheem unit might be your match.


  • Immediate hot water with minimal waiting
  • Compact and wall-mountable, saving floor space
  • Overheat protection for peace of mind


  • Installation may be challenging for some
  • Additional costs for accessories not included
  • Potential humming noise as noted in a review

Tankless water heaters are game-changers for your home comfort, and this Rheem model is no exception. It provides a consistent supply of hot water on demand, so you’re not left shivering while the shower warms up. With the Hot Start Programming feature, those jarring cold bursts are history when you’re taking back-to-back showers.

Despite its robust performance, the sleek and unobtrusive design is a major win. It fits snugly on a wall, which can free up your floor space for other uses. This is especially handy in smaller homes or apartments where every square foot counts. And because it’s powered by natural gas, you can look forward to potential savings on your electricity bill.

Still, even the best products have potential drawbacks. Installation might pose a challenge, especially if you’re not a DIY pro, so consider the cost of professional installation when budgeting. Moreover, you might find yourself purchasing necessary accessories that are not included with the heater itself.

And finally, do take note of the humming mentioned by a user — though it may not be a dealbreaker, it’s worth keeping in mind.

FOGATTI InstaGas Classic 120 Series

If you’re seeking a compact, efficient gas tankless water heater, the FOGATTI InstaGas 120 Series could be a perfect fit for your home’s hot water needs.


  • Compact design saves space
  • Provides an instant and continuous hot water supply
  • Precise temperature control within ±2°F


  • Not suitable for high-altitude installation above 2000 feet
  • Requires a well-ventilated area for safe operation
  • Additional cost for the necessary 3-inch diameter exhaust pipe

Imagine never running out of hot water in the middle of your shower and having more room in your utility closet. Well, with FOGATTI’s InstaGas 120 Series, that can be your new reality. The slim profile makes it a huge space saver compared to traditional tank units.

You’re probably used to waiting for water to heat up – not anymore. This water heater’s innovative heat exchanger technology means you’ll get hot water quickly, keeping the flow consistent for as long as you need.

Hazards with water pressure spikes are a thing of the past. Integrated components in the FOGATTI InstaGas system provide safety and peace of mind, significantly reducing the chances of pressure-related issues.

Installation is not a headache as feared. Most homes with existing tank water heaters will find the FOGATTI’s connections are highly compatible, easing the transition process. Nevertheless, the safest bet is to have a licensed professional handle the installation to ensure it complies with local codes.

Service and support are a big deal for any appliance. FOGATTI’s commitment is evident with their robust warranty and CSA certification. It’s clear they stand behind the reliability and safety standards of their product.

To put it simply, the FOGATTI InstaGas 120 Series brings warmth to your home in a more efficient, space-saving way, contributing to a pleasant and hassle-free hot water experience.

Takagi T-H3J-DV-N

Imagine the convenience of endless hot water for your entire home, even if you have a high demand or live in a colder climate – the Takagi High-Efficiency Tankless Heater makes it possible.


  • Supplies ample hot water without the wait for multiple bathrooms
  • Efficient energy usage that could lower monthly bills
  • Compact size frees up space compared to traditional water heaters


  • Higher upfront cost compared to standard tank heaters
  • Professional installation recommended, which adds to initial expenses
  • May require larger gas lines and additional venting

Upgrading to a tankless water heater often seems daunting, but the benefits are tangible. With the capability to heat water for up to four bathrooms in warm climates and three in cooler areas, the Takagi unit is a robust solution for both residential and light commercial needs. Its high BTU input ensures that hot water flows steadily, even with multiple taps in use.

Selecting a water heater involves considering running costs and environmental impact. This model’s energy-saving features and compliance with Ultra-Low NOx regulations represent a thoughtful purchase for the eco-conscious homeowner.

Furthermore, the absence of a pilot light and incorporation of advanced safety diagnostics point towards a user-friendly design.

This compact powerhouse occupies less room than traditional tanks, freeing up space in your home. Energy Star certification implies potential savings on utility bills, which could balance the upfront investment over time.

If you’re transitioning from a regular tank to this high-efficiency tankless model, consulting a professional for installation is a wise choice to ensure optimal performance and compliance with safety standards.

MIZUDO 3.6 GPM Heater

If you’re in search of a reliable gas tankless water heater, the MIZUDO may be a fitting choice for its efficiency and compact design.


  • Infinite on-demand hot water for multiple points of use
  • Precise temperature control for a comfortable experience
  • Space savings with a compact, efficient design


  • Requires manual reboot after power outages
  • The maximum flow rate might not meet high simultaneous demands
  • Some users have reported maintenance issues within months

Your quest for endless hot water might just end with this sleek, compact gas tankless water heater by MIZUDO. Imagine the convenience of hot water whenever you need it, without the bulk of a tank. You save space and enjoy a continuous flow, making chilly showers a thing of the past.

Ease of installation is another win. You don’t need to be a plumbing wizard to get this heater up and running. However, if the power goes out, remember you’ll need to manually reset the system—an important detail for those who travel often or dislike the hassle of manual resets.

This unit’s modern design doesn’t only look good, it also translates to energy efficiency. By only heating water as you use it, you’re looking at potential savings on your utility bills. But while the MIZUDO impresses on many fronts, some users have encountered maintenance issues.

Keeping track of the warranty and support options is a smart move.

In summary, the MIZUDO 3.6 GPM tankless water heater provides hot water efficiently and on demand, with a seamless temperature control that elevates your daily routines. Its few drawbacks are worth considering, but they don’t detract from the overall quality and value it offers to your household.

Buying Guide

Assess Your Needs

Firstly, evaluate your hot water usage patterns. How many people are in your household? How many appliances need hot water simultaneously? According to your demand, water heaters are rated by Gallons Per Minute (GPM). Choose a unit with a GPM rating that matches your peak usage.

Energy Efficiency

Energy Factor (EF) ratings are crucial. Look for a higher EF rating, as it indicates a more efficient unit that can save you money in the long run.

Size and Installation Space

Tankless water heaters are compact, but you’ll still need to measure the space where you plan to install it. Ensure it can fit and that there is proper ventilation.

Fuel Type

You’ll have to choose between electric and gas models. Consider the availability and cost of these fuel types in your area, and if you’re opting for gas, think about whether you’ll use natural gas or propane.

Temperature Rise

Calculate temperature rise by subtracting your incoming water temperature from your desired hot water temperature. The greater the rise needed, the more powerful your heater should be.


Examine features like digital displays, which allow you to adjust the temperature and monitor system performance, and self-modulating technology, which adjusts energy usage based on demand.

Remember, warranties vary, so choose a model with a warranty period that gives you peace of mind. Installation should be handled by a professional to ensure safety and compliance with local codes.

How to Install a Gas Tankless Water Heater

Before you begin, it’s essential to consider whether you’re experienced in DIY projects, especially those involving gas lines. If you’re not, it’s highly advisable to hire a professional for safety reasons. However, if you choose to proceed with self-installation, here are the primary steps you should follow:

  1. Choose the Right Model: Ensuring you have the appropriate size and type for your home’s needs is crucial.
  2. Turn Off Utilities: Shut off the main gas supply and water lines.
  3. Remove Old Heater: If a previous heater is present, disconnect and carefully remove it.
  4. Mount the New Heater: Securely mount your tankless heater on a wall with proper clearances around it.
  5. Connect Gas Supply: Attach the gas line to the new heater, using a leak detection solution to check connections.
  6. Water Line Hook Up: Connect the water lines, both hot and cold. Ensure that all fittings are secure.
  7. Ventilation: Properly install the vent system according to manufacturer instructions and local codes.
  8. Electrical Supply: If your tankless heater requires an electrical connection, make sure to connect it to an appropriate power source.
  9. Final Checks: Before turning everything back on, double-check all connections for gas and water leaks.
  10. Test the Unit: Carefully restore power and water, then test the unit to make sure it’s operating correctly. Make the gas and water lines are connected correctly.

Tools Required:

  • Adjustable wrenches
  • Screwdrivers
  • Pipe wrenches
  • Teflon tape
  • Leak detection solution

Remember, any step involving gas or electrical connections requires attention to detail and adherence to safety practices. Don’t hesitate to refer to the manufacturer’s manual for specifications and guidance.

Care and Maintenance for Gas Tankless Water Heaters

Proper maintenance is key to ensuring your gas tankless water heater runs efficiently and lasts a long time. Here are some friendly tips to help you take care of your unit:

  1. Annual Inspection: Make it a habit to have your water heater checked by a professional once a year. This includes looking for any signs of wear or damage, ensuring that the venting system is not obstructed, and that the water and gas connections are secure.
  2. Filter Cleaning: Your water heater has an in-line screen filter that should be cleaned regularly. Simply turn off the water supply, remove the filter, rinse it out, and replace it. This prevents build-up and maintains water flow.
  3. Flushing: Over time, minerals can accumulate in your heater. To avoid this, flush the system with a vinegar solution every six months. This will remove the sediments and maintain heater efficiency.
  4. Air Supply: Ensure there’s adequate air supply for proper combustion. Keep the surrounding area of your heater free from dust and debris.
  5. Water Softeners: If you have hard water, consider installing a water softener. This can reduce scale buildup in the system.
  6. Proper Use: Avoid overloading your water heater by running too many appliances at once. This ensures you don’t strain the system and can prolong its lifespan.
  7. Error Codes: If your heater displays error codes, refer to the manual to troubleshoot or call a technician if you can’t resolve the issue.

By following these straightforward guidelines, you’ll enjoy uninterrupted hot water and potentially save on energy and repair costs. Remember, taking care of your gas tankless water heater is an ongoing responsibility that pays off in the long run.

Final Verdict

After thorough research and evaluation, the top two choices for the best gas tankless water heaters in 2024 are the Rinnai RU160iN and the Rheem RRTGH95DVLN3701177.

The Rinnai RU160iN stands out for its combination of high efficiency, space-saving design, and reliable performance. It provides an endless hot water supply on demand, with a strong water pressure of up to 9 GPM.

While professional installation may be required, the long-term benefits of non-stop hot water and reduced energy costs make it a smart investment for any household.

On the other hand, the Rheem RRTGH95DVLN3701177 offers immediate hot water with minimal waiting time, compact wall-mountable design, and overheat protection for peace of mind.

Despite potential challenges with installation and additional costs for accessories, its consistent supply of hot water and energy-saving features make it a top contender in the market.

In conclusion, whether you prioritize efficiency, performance, or space-saving design, both the Rinnai RU160iN and the Rheem RRTGH95DVLN3701177 offer excellent options for upgrading your hot water system to a gas tankless water heater.

Choose the one that best fits your household’s needs and enjoy the benefits of endless hot water and energy savings for years to come.

When selecting a gas tankless water heater:

  • Prioritize Efficiency: Higher efficiency ratings translate to lower operating costs over the heater’s lifespan.
  • Flow Rates Matter: Make sure the unit can handle your peak hot water demands.
  • Consider the Installation: Factor in installation flexibility and potential costs.
  • Think Long-Term: Invest in a model known for durability and backed by a solid warranty.

By keeping these tips in mind, you’ll find a gas tankless water heater that aligns closely with your household’s needs and preferences.

Frequently Asked Questions

In this section, you’ll find answers to common questions about gas tankless water heaters, helping you make an informed decision regarding your home’s water heating needs.

What are the pros and cons to choosing a gas tankless water heater?

Gas tankless water heaters offer endless hot water and lower operating costs compared to traditional tank models, due to their on-demand heating functionality. However, many tankless water heaters can have higher initial installation costs and may require venting modifications to your home.

Can a gas tankless water heater work for a whole house?

Yes, a properly sized gas tankless water heater can supply consistent and continuous hot water for an entire home. It’s essential to ensure the heater’s flow rate meets your peak hot water demand.

How do I choose the right size gas tankless water heater?

To determine the right size, calculate the flow rates of all fixtures you expect to use simultaneously and add them up to find the total flow rate. Your water heater should meet or exceed this rate at your groundwater temperature.

Are gas tankless water heaters eco-friendly?

Gas tankless water heaters are more eco-friendly than traditional tank heaters, as they heat water on demand and reduce standby energy losses. However, they still use fossil fuels, making their environmental friendliness relative to their efficiency and the source of the gas.

Are there significant differences in efficiency between gas and electric tankless water heaters?

Electric water heaters often have higher efficiency ratings than gas models, as they convert almost all the electricity into heat without exhaust losses. Gas models are less efficient overall but may cost less to operate depending on local utility prices.

What is the difference between condensing and non-condensing water heaters?

Condensing water heaters recover heat from exhaust gases through condensation, boasting efficiency ratings over 90% and lower operating costs with PVC venting. Non-condensing models, in contrast, release exhaust gases directly, resulting in lower efficiency, higher costs, and metal flue venting. Though condensing heaters are pricier initially, their long-term efficiency benefits outweigh the costs, making them environmentally friendly and cost-effective choices.


  • Edmund Yeo

    🌱 I'm passionate about sustainable living and renewable energy, and I'm thrilled to share my journey towards a greener, brighter future with you. Join me as I explore the latest innovations, eco-friendly lifestyle tips, and inspiring stories from the forefront of the green energy revolution. Note: This website uses affiliate links which may earn a commission for purchases made at no additional cost to you.

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