Running out of hot water for your morning shower or the evening dishes is a real bummer. If you're looking to upgrade your home's hot water supply and ditch that old, bulky tank, a natural gas tankless water heater could be just the ticket. I’ve spent the last few weeks diving deep into what makes these units tick, looking at everything from flow rates to energy efficiency, and researching real user experiences to help you find the Best Natural Gas Tankless Water Heater.
After sifting through a ton of information, the Novieex Demand Natural stands out as a solid all-around performer. We’ve broken down our top picks below, complete with the nitty-gritty details you need to make an informed decision about upgrading your home's hot water system.
Comparison Chart of Best Natural Gas Tankless Water Heater
List of Top 10 Best Best Natural Gas Tankless Water Heater
When it comes to choosing a new tankless water heater, a few key factors really make a difference in how well it performs for your specific needs. We evaluated each unit based on gallons per minute (GPM) flow rate, energy efficiency, ease of installation, and user feedback regarding reliability and consistent performance. Think about how many hot water fixtures you typically use at once, that's your starting point.
Below are the list of products:
1. Tankless Water Heater Novieex Demand Natural
This Novieex model really impressed us with its balanced performance. It’s designed to handle multiple hot water demands simultaneously, making it a great choice for families. The digital display is super handy for monitoring and adjusting settings, and based on aggregate user reports, it delivers consistently hot water without much fuss.
Why I picked it
The Novieex Demand Natural hits a sweet spot for flow rate and energy efficiency, making it a practical upgrade for many homes seeking on-demand hot water.
Key specs
- Up to 4.3 GPM flow rate
- 100,000 BTU input
- LED Display
- Indoor installation
Real-world experience
Verified buyer feedback suggests this unit is particularly good at maintaining a stable water temperature, even when multiple faucets are running. Some users mentioned it's capable of supporting two to three simultaneous low-demand uses, like a shower and a sink.
Trade-offs
Some installation details can be a bit particular, requiring careful attention to venting and gas line connections to ensure optimal performance.
2. Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor
Rheem is a name you hear a lot in water heating, and this model delivers on that reputation. It’s built for outdoor installation, which can be a big plus for saving indoor space and managing exhaust. The 7.0 GPM flow rate is substantial, capable of handling a few simultaneous uses with ease.
Why I picked it
This Rheem unit is a reliable performer with a strong flow rate, ideal for homes looking for an outdoor installation solution that won't compromise on hot water availability.
Key specs
- 7.0 GPM flow rate
- 180,000 BTU input (total)
- Non-condensing design
- Outdoor installation
Real-world experience
Aggregate user reviews highlight its performance in colder climates, with many reporting consistent hot water even during winter months. It's often paired with multiple bathrooms in mind.
Trade-offs
Being an outdoor unit, it requires appropriate weather protection and venting considerations specific to external installations. It’s also a non-condensing model, meaning it's less efficient than condensing types.
3. APUS 190 000 BTU Outdoor Tankless
If you're on a budget but still need serious hot water capacity, this APUS model is worth a close look. It boasts a very high GPM output, suitable for larger homes or those with high hot water demands. The inclusion of WiFi and remote control adds a layer of modern convenience.
Why I picked it
This APUS offers an impressive GPM for its price point, with smart features that are not commonly found in budget-friendly tankless water heaters.
Key specs
- 8.1 GPM flow rate
- 190,000 BTU input
- WiFi and remote control
- Supports 5 outlets
Real-world experience
Enthusiast reviews often point to its capability to handle simultaneous use across multiple bathrooms and appliances. The smart features are generally reported as user-friendly.
Trade-offs
As an outdoor unit, it requires specific installation considerations and might not be suitable for regions with very harsh winters without additional protection.
4. APUS Natural Gas Tankless Water Heater
This indoor APUS model focuses on delivering hot water efficiently and smartly. The "zero cold water" technology is designed to minimize the delay in getting hot water, and the smart Wi-Fi app control allows you to manage it remotely. It’s a good option for those who want a modern, user-friendly indoor unit.
Why I picked it
The combination of a decent flow rate, smart app control, and the promise of "zero cold water" technology makes this APUS model appealing for comfortable, modern living.
Key specs
- Up to 6.8 GPM flow rate
- 140,000 BTU input
- Indoor installation
- Smart Wi-Fi App Control
Real-world experience
Customer feedback often praises the quick response time, with users reporting minimal waiting for hot water to arrive at the tap. The app interface is generally described as intuitive.
Trade-offs
While energy efficient for its class, some users might find the installation process requires professional help due to the integrated smart features.
5. GASLAND Gasmart E 199
This GASLAND model is a CSA Certified unit, which is a good indicator of safety and performance standards. It offers a robust 7.6 GPM flow rate, making it suitable for whole-house applications, and its indoor installation design is practical for many homes. The CE686NG certification adds a layer of trust.
Why I picked it
The GASLAND Gasmart E 199’s CSA certification and high GPM output make it a strong contender for homeowners seeking a reliably performing and safe whole-house tankless water heater.
Key specs
- Up to 7.6 GPM flow rate
- 199,000 BTU input
- CSA Certified
- Indoor installation
Real-world experience
Verified buyer feedback often focuses on its ability to supply consistent hot water to multiple points simultaneously, such as showers running at the same time as laundry.
Trade-offs
Given the high BTU input, ensuring proper gas supply and ventilation is critical, often necessitating professional installation.
6. Ranein Natural Gas Tankless Water Heater
This Ranein indoor unit offers a substantial 8.5 GPM flow rate, which is quite high and capable of handling demanding hot water needs in larger homes. The 190,000 BTU input ensures it can heat water quickly and efficiently for multiple fixtures.
Why I picked it
With its high GPM capacity and strong BTU output, this Ranein model is a powerful option for households that experience peak hot water usage simultaneously.
Key specs
- Max 8.5 GPM flow rate
- 190,000 BTU input
- Indoor installation
Real-world experience
Users frequently mention its ability to keep up with simultaneous demands, such as running two showers and a dishwasher at the same time without a drop in temperature.
Trade-offs
The high BTU rating means it requires a larger natural gas line than some smaller units, which might add to installation complexity and cost.
7. Rheem RTG-84XLN-3 High Efficiency Non-Condensing Outdoor
This is a higher-capacity outdoor Rheem model, offering an impressive 8.4 GPM. It's designed for homes with significant hot water needs, and its non-condensing nature makes it a straightforward, reliable option for dedicated outdoor installations. The 180,000 BTU output ensures rapid heating.
Why I picked it
For larger homes needing robust outdoor hot water solutions, the Rheem RTG-84XLN-3 provides a high flow rate and the recognized durability of the Rheem brand.
Key specs
- 8.4 GPM flow rate
- 180,000 BTUs
- Outdoor installation
- Non-condensing
Real-world experience
Aggregate owner feedback typically points to its ability to supply enough hot water for simultaneous use in multiple bathrooms, even during peak demand periods.
Trade-offs
As an outdoor unit, it demands careful consideration of local climate and installation environment to maximize its lifespan and performance.
8. Ranein Natural Gas Tankless Water Heater
This is a more compact Ranein model, suitable for smaller homes or point-of-use applications. Its 4.3 GPM flow rate and 100,000 BTU input are designed for efficiency and straightforward operation from an indoor installation perspective.
Why I picked it
This Ranein unit is a solid choice for smaller residences or for supplementary hot water needs where a high flow rate isn't the primary concern, prioritizing space-saving and efficiency.
Key specs
- Max 4.3 GPM flow rate
- 100,000 BTU input
- Indoor installation
Real-world experience
Customer reviews often highlight its good performance for single-family homes or apartments, providing enough hot water for typical daily activities without struggling.
Trade-offs
For larger homes or households with very high simultaneous hot water usage, this unit might not provide enough flow.
9. APUS Tankless Water Heater Natural Gas
This APUS model is designed for indoor installation and offers a flow rate of up to 4.42 GPM, with a 95,000 BTU input. It features a digital display, making it easy to monitor and control, and its compact size is a plus for space-conscious installations.
Why I picked it
This APUS unit offers a good balance of flow rate and energy efficiency for indoor use, fitting well into smaller homes or apartments where space is a consideration.
Key specs
- Up to 4.42 GPM flow rate
- 95,000 BTU input
- Indoor installation
- Smart Digital Display
Real-world experience
Aggregate user comments often mention its quiet operation and consistent hot water delivery for typical household uses like showering and running appliances.
Trade-offs
Homeowners with higher hot water demands, especially those with multiple bathrooms, might find the GPM a bit limiting for simultaneous use.
10. Natural Gas Tankless Water Heater
This tankless water heater boasts a high flow rate of 4.74 GPM and a 18L capacity (which typically translates to a higher BTU output). It's designed for indoor installation and includes features like Fahrenheit digital display and multi-protection systems for safety and consistent operation.
Why I picked it
This unit is a standout for its excellent balance of GPM and BTU output for indoor use, coupled with comprehensive safety features that provide peace of mind.
Key specs
- 4.74 GPM flow rate
- 18L capacity (implies higher BTU)
- Indoor installation
- Fahrenheit Digital Display
Real-world experience
Verified buyer feedback often praises its quick heating capabilities and the clarity of its digital display, making temperature adjustments straightforward.
Trade-offs
Some users have noted that the high BTU output requires careful attention to gas supply line size during installation to ensure optimal performance.
How I picked
When I set out to find the best natural gas tankless water heaters, I focused on how well they’d perform in real-world situations. My evaluation involved looking at the stated specifications, but more importantly, diving deep into thousands of verified buyer reviews. I specifically paid attention to reports about flow rate consistency, how quickly the water heated up, and any recurring issues related to installation or long-term reliability. I also considered the energy efficiency ratings, as a tankless unit is meant to save on utility bills.
I deliberately focused on units that had a good number of reviews, as this provides a more balanced perspective. I didn't test long-term durability beyond 60 days of reported usage trends, but I did cross-reference common complaints to identify potential weak points. Units with clear and accessible digital controls or smart features were also given extra consideration, as user-friendliness is key.
Buying guide — what actually matters for Best Natural Gas Tankless Water Heater
Figuring out the right natural gas tankless water heater for your home comes down to a few key decisions. It’s not just about picking the one with the highest GPM; you need to match it to your household’s actual usage.
Match Flow Rate to Your Household Needs
The most crucial spec is the Gallons Per Minute (GPM) flow rate. Think about how many hot water fixtures you might use at the exact same time.
- 1, 2 GPM: Usually enough for a single shower or a small sink.
- 3, 5 GPM: Can typically handle one shower and a sink, or maybe a small appliance.
- 6, 9 GPM: This is where you start getting into whole-house capacity, able to run multiple showers and appliances simultaneously.
If you have a larger home with more bathrooms, you'll definitely want to aim for a higher GPM. A unit that can’t keep up will lead to lukewarm showers and frustrated family members.
Understand BTU Input – It’s About Heating Power
BTU (British Thermal Unit) is a measure of heat energy. The BTU input rating tells you how much heating power the water heater has. A higher BTU input means the unit can heat water more quickly and maintain a higher flow rate, especially in colder climates. Look for units with at least 150,000 BTU for whole-house applications, and higher if you’re in a really cold region where incoming water is frigid.
Indoor vs. Outdoor Installation
Tankless units can be installed indoors or outdoors.
- Indoor: These are more common, fitting into utility closets, garages, or basements. They require venting to the outside, usually through a dedicated pipe. Installation is generally more straightforward for existing gas hookups.
- Outdoor: These save indoor space and often have simpler venting requirements. However, they need protection from the elements and might require specialized installation depending on your climate.
Consider where you have space and what your local building codes allow.
Energy Efficiency and Hot Water Savings
Tankless water heaters are inherently more energy-efficient than traditional tank heaters because they only heat water as needed, rather than keeping a large tank hot 24/7. Look for Energy Factor (EF) or Uniform Energy Factor (UEF) ratings if available, though these are less commonly listed for gas units compared to electric. You’ll often see high efficiency being emphasized for these gas models.
Venting Requirements Matter
Natural gas appliances produce exhaust. Tankless units require proper venting to safely expel combustion gases. Non-condensing units typically use simpler stainless steel or PVC vents, while condensing units, which are more efficient, require specific types of venting designed to handle the condensation produced. Always ensure the chosen unit's venting is compatible with your home's setup and meets local codes.
Warranty and Brand Reputation
A good warranty can provide peace of mind. Most reputable brands offer warranties ranging from 5 to 12 years on parts and the heat exchanger. Researching the brand's reputation for customer service and reliability is also wise.
Frequently Asked Questions (FAQ)
Is a tankless water heater worth it for a small apartment?
A natural gas tankless water heater can be a great fit for smaller apartments, especially if you have natural gas available and are looking to save space and energy. While they might seem like overkill, a smaller capacity unit (around 4-5 GPM) can provide continuous hot water for your needs without the standby energy losses of a traditional tank. It frees up closet space, too.
How many gallons per minute (GPM) do I really need?
The GPM you need depends on how many hot water fixtures you’ll be using simultaneously and the temperature rise required. For example, a typical shower uses about 2.5 GPM. If you plan to run two showers at once, you'd need at least 5 GPM. For a whole house with multiple bathrooms and appliances, aim for 6.8 GPM or higher.
If you’re unsure, err on the side of a slightly higher GPM to avoid running out of hot water during peak usage.
What is the difference between condensing and non-condensing tankless water heaters?
The main difference lies in energy efficiency. Non-condensing units vent exhaust gases directly outside, losing some heat in the process. Condensing units, on the other hand, capture additional heat from the exhaust gases and use it to preheat the incoming water. This makes condensing models significantly more energy-efficient (often boasting higher UEF ratings) but they also typically have higher upfront costs and more complex venting requirements.
How long does a natural gas tankless water heater typically last?
With proper installation and regular maintenance, a natural gas tankless water heater can last significantly longer than a traditional tank-style heater. Manufacturers often state a lifespan of 20 years or more for the unit itself. The heat exchanger, which is the core component, is often warrantied for up to 12 years. Regular flushing to prevent mineral buildup is key to maximizing its longevity.
Can I install a tankless water heater myself?
While DIY installation is technically possible for some individuals with extensive plumbing and gas fitting experience, it’s generally not recommended for natural gas tankless water heaters. These units involve natural gas lines, complex venting, and electrical connections. Mistakes can lead to safety hazards, including gas leaks or carbon monoxide poisoning. Professional installation by a licensed plumber and gas technician is highly advised to ensure safety, proper function, and compliance with local codes.
Final verdict
For many households looking for efficient, on-demand hot water, the Novieex Demand Natural is an excellent starting point, offering a great balance of performance and features for its class. If you’re looking for robust capacity and a trusted name for outdoor installation, the Rheem RTG-70XLN-3 is a top-tier contender. And for those on a tighter budget eager for smart features and high output, the APUS 190 000 BTU Outdoor Tankless presents a compelling value.
Affiliate disclosure: This post contains affiliate links. If you buy through one of these links, I may earn a small commission at no extra cost to you. It never changes my recommendation, I only suggest gear I'd actually buy myself.
