Best Tankless Gas Water Heater

November 2023

If you’re looking to upgrade your current hot water heater, then you’ve come to the right place. Here you’ll find information on the best tankless gas water heaters on the market. Our top picks include the Noritz NRC66DVNG, Westinghouse WRGTNG199, Rinnai RU199iN Sensei, and Excel i12-NG. If you’re still on the fence about whether a tankless gas water heater is for you, then read on to find out which model has the best features.

Rheem 240V 2 Heating Chambers RTEX-18

The Rheem 240V 2 Heating-Chambers RTEX-18 is a self-modulating electric indoor inline water heater that uses 240 volts to heat your water. It is 99% efficient, which means you can save on your energy costs from the first month. The RTEX-18 is made from high-quality materials and components. However, it’s not perfect. The unit may not heat as fast as some other brands, but it’s still a good choice if you need a self-modulating heater that doesn’t take up much space.

Rheem RTEX-18

The Rheem RTEX-18 is a residential tankless water heater that uses 240 volts to heat water. It heats water at a constant temperature and can deliver up to seven gallons of hot water per minute. It is a fast and easy to install unit that heats water quickly and efficiently.

The RTEX-18 features two long-lasting copper immersion heating elements, which improves its performance and durability. It also has a brass top for superior heating and threaded heating elements, which provide a higher flow rate.

Rheem RTEX-18 240V 2 Heating Chambers

The Rheem RTEX-18 230V 2 Heating Chambers Residential Tankless is a powerful, efficient tankless water heater. With 99% energy efficiency, it can significantly cut your energy bill from the first month. It’s easy to operate and comes with high-quality materials. The gray design of the tankless water heater gives it a sleek profile. It doesn’t require a lot of space for installation.

This model can be installed in a manufactured home that has already been installed to minimum code. It can be used in single or limited multi-applications, and it requires a 1/2-inch-NPT side water connection. It can also be upgraded to a three-element model later. The RTEX-18 is also equipped with advanced self-modulation, which reduces power consumption during periods of low demand.

Rheem RTEX-18 self modulating electric indoor inline water heater

The Rheem RTEX-18 self-modulating electric indoor inline water heater is a powerful yet simple unit that runs on mains electricity. It can be powered by a single circuit breaker or 240 volts, and it does not need venting. It features a digital LED display and anti-corrosive internal parts. Its copper immersion heating elements and brass tops are sturdy and durable.

Another great feature of the RTEX series is its dual flush capability, which means it can run multiple fixtures at once. This unit also has an impressive 4.4 GPM flow rate, which is higher than average for units in its size class. As long as the incoming water temperature is optimal, the RTEX-18 can easily keep up with your hot water demand. Furthermore, this model can heat water to 140 degrees, which is higher than most units in its class.

Rheem RTEX-18 operating on 240 volts

If you are looking for a tankless electric water heater, you can choose from the Rheem RTEX-06 or Rheem RTEX-18 models. They operate on 240 V and provide 5.5 kW of power. They are also capable of providing 1.5 GPM to one fixture. These heaters feature simple controls, such as push-button on and off controls and external LED temperature displays.

Among other benefits, the Rheem RTEX-18 operates on 240-volt electricity and is easy to install. It can also be run by a single power source. It requires 240-volt power and two 40-amp circuit breakers. It does not require venting and comes with an LED digital display and anti-corrosive internal parts. The heating element is composed of robust copper and brass.

Rheem RTEX-18 installation

If you’re preparing to install a tankless water heater, the Rheem 240V 2 Heating chambers RTEX-18 Residential Tankless may be the right choice for your home. This product uses a self-modulating design that adjusts the unit’s power to hot water demands. This reduces the risk of discontinuous performance.

This tankless water heater is designed for point-of-use installation. It is suitable for homes with lower ground temperatures. Its single heating chamber has a power rating of 5.5 kW, which is enough to heat a one-flight-feet room. It is equipped with a push-button ON/OFF control and an external LED temperature display.

Marey GA24CSALP Propane Tankless Water Heater

The MAREY GA24CSALP is a Tankless Water Heater with a minimum BTU of 24,000 and a maximum BTU of 170,000. The unit has a water pressure range of 15-150 MPa and a propane gas inlet pressure range of 8.0-1.99 kPa. It weighs a net weight of 40.8 lbs – 18.5 kg and measures 665 x 435 x 186.5 mm.

Propane Tankless Water Heater

The MAREY GA24CSALP PropanE Tankless Water Heater is a great choice for anyone who is looking for a low-maintenance and energy-efficient option for their home. With a maximum input rating of 170,000 BTU/hr and a flow rate of 8.34 GPM at a 35F temperature rise, this unit is perfect for any size home, apartment, cabin, or small commercial space.

This unit comes with a built-in back-draft prevention device and stainless steel horizontal vent pipe. It also has a flame failure device, child lock technology, and fully automatic temperature control.

Whole house indoor solution

The Marey GA24CSALP is a tankless water heater with a minimum BTU of 24,000 and a maximum BTU of 170,000. It is CSA certified for the US and Canada market and has a water pressure range of 15-150 MPa and propane gas inlet pressure of 8.0-1.99 kPa. The unit weighs approximately 40.8 lbs. (18.5 kg) and has dimensions of 665 x 435 x 186.5mm.


The Marey GA24CSALP Tankless Water Heater has a BTU rating of up to 170,000 and an input temperature range of 15-150 MPa. It also comes with advanced safety features, such as flame failure and overheating protection. It is CSA-certified for use in the US and Canada. This unit is designed with a compact, streamlined design and a copper heat exchanger for optimal heating and cooling performance.


The Marey GA24CSALP is an excellent tankless water heater with a minimum BTU of 24,000 and a maximum of 170,000 BTU. It is designed for a variety of homes and has a water pressure range of 15-150 MPa and a propane gas inlet pressure range of 8.0-1.99 kPa. It weighs approximately 40.8 pounds or 18.5 kg, and its dimensions are 665 x 435 x 186.5 mm.

Onsen – 14L Direct Vent Tankless Natural Gas Water Heater

The Onsen – 14L Direct Vent is a small, energy-efficient tankless water heater for indoor use. Designed with a compact design and CSA certification, this product can be installed in a remote location or off-grid home. It ships from Quebec and will arrive in 6 to 8 business days in Alberta. This compact, energy-efficient tankless natural gas water heater requires less than one amp of electricity.

NPN series non-condensing tankless natural gas water heaters

Navien Inc. has introduced a new 120,000-BTU model to the company’s NPN series. This is the fourth model in Navien’s NPN-E (exterior) line and is available in both natural gas and liquid propane configurations. Designed for outdoor use, the NPN-120E provides 4.2 gpm at 45 degrees Fahrenheit and 0.81% UEF. Compared to its predecessors, the NPN series is much smaller than the NPE line, and takes up 80% less space.

Ensure proper gas pressure is present in the tankless water heater. This is crucial for proper operation. You need to ensure that the valve is open and that you have paid the gas bill. If the system is frozen, hot water may not reach all appliances. To fix this problem, thaw the pipes naturally, and stop overloading the system. In case of a malfunctioning water heater, you must set the thermostat back to 120 degrees Fahrenheit.

Power vent gas water heaters

Power vent gas water heaters are among the best choices for homeowners that require ample amounts of hot water. These water heaters can deliver sufficient hot water for your home without compromising your family’s health. Rheem PROG50-42N RH67 PV and AO Smith GPHE-50 models are examples of excellent power vent gas water heaters. These water heaters have the following features:

The electrical blower fan of a power vent water heater forces combustion air to escape the water heater and the surrounding area. This fan is connected to a nearby electrical outlet. Besides, power vent gas water heaters do not use fuel, which makes them economical to operate. These heaters also contain a built-in shutoff mechanism that automatically powers off the water heater if the fan stops working. Moreover, the longer exhaust venting line allows more freedom in locating your water heater.

The Onsen 14L Direct Vent Tankless Indoor Gas Water Heater is a great option for a home that wants hot water when you need it. It uses natural gas to heat water and activates with an electronic ignition system. With a direct vent system, the Onsen does not require two exhaust vent pipes, which means that it can be installed in a smaller space. Another great feature is its control panel, which features an LED display.


The Onsen 14L Indoor Gas Tankless Water Heater transforms cold water into hot water when you need it. This device uses natural gas as its fuel source and operates on an electronic ignition. It features a direct vent system to prevent warm indoor air from escaping the home. You can easily control the heater’s operation using the included control panel and LED display. Once installed, the Onsen 14L will keep your bathroom warm.

When using the Onsen 14L Direct Vent Tankless Water Heater, it is important to follow installation instructions carefully to ensure the safety of your family. Despite its low energy consumption, the Onsen 14L Direct Vent Tankless Natural Gas Water Heater may produce a foul odour. You can detect gas leaks by soaking a clean piece of cloth in a soapy solution. However, if you are not sure about gas pipe connections, it is best to contact a licensed contractor for this job.

RINNAI Ru Series Sensei Se+ RU160in

The Sensei series offers a wide variety of features and options. The condensing technology allows these units to operate in the coldest temperatures, and the integrated freeze protection system prevents them from becoming damaged by extreme cold. The condensing system also has an integrated check valve to prevent cold air from entering and backflow of exhaust during common vent applications. The Fiber Mesh Premix Burner helps maintain even flame distribution and optimal performance for any demand.

Sensei Ru Series

The RU160 is part of the Rinnai Sensei SE+ Series, a line of ultra-efficient tankless water heaters. Available in two fuel options, Liquid Gas and Natural Gas, the Sensei SE+ Series is ideal for both indoor and outdoor installations. Its dual venting option provides two separate routes for hot water and waste. You can easily install the Rinnai Sensei Se+ on your outdoor kitchen or patio.

Sensei Se+

The Sensei Series from Rinnai features a condensing burner with a high efficiency factor (UEF) of 0.85 or higher. The SE line-up of condensing tankless water heaters achieves UEF ratings between 0.85 and 0.90 and is not ENERGY STAR qualified. The SE+ Series is available in RUCS and RUS models, which both use natural gas or propane to meet indoor water heating needs.

Sensei Se+ Series condensing tankless water heater

The RINNAI Ru Series and Sensei Se+ Series condenser water heaters are both made by the manufacturer of Japanese-made appliances. The latter is known for its environmentally-friendly features and low NOx emissions. Both have zero clearance and sealed combustion and are available with various features. However, the cost of a condensing tankless water heater is higher than that of a non-condensing unit. The former is more cost-effective to buy but requires more gas, so you will need to choose carefully.

Sensei Se+ Series installation

The Rinnai Sensei water heater provides homeowners with flexible installation options. This water heater is equipped with 14 different venting options and offers an industry-leading maximum venting run of 65 feet. The Sensei also features easier maintenance, as every component can be removed in less than 10 minutes. It is Wi-Fi enabled and includes Amazon Alexa integration. These water heaters are designed to meet the highest quality standards.

Rheem RTGH-95

If you want a high-flow, energy-efficient tankless water heater, the Rheem RTGH-95DVLN-2 is an excellent choice. Compared to its Rinnai counterpart, the Rheem is less expensive and still offers excellent water flow and efficiency. It’s a perfect fit for large homes with multiple bathrooms, thanks to its energy-efficient design and 9.5 gpm capacity. Its continuous hot water delivery ensures that you will never run out of hot water.

Another benefit of this Rheem tankless gas water heater is its high-efficiency condensing technology. Unlike a tank-style heater, this model is able to withstand freezing temperatures of up to 30 degrees below zero. It also features a self-diagnostic utility that can automatically monitor its function and alert you to any potential problems with the gas or water supply. It also features a self-diagnosis feature, which helps you troubleshoot any potential problems before you start experiencing problems.

The Rheem RTGH-95 is part of the Prestige Series, a collection of high-efficiency condensing tankless gas water heaters. The Prestige models all surpass ENERGY STAR requirements. Other features include an exclusive water savings setting and a built-in condensate neutralizer. The Prestige Series is also available in a commercial model for high temperatures.

Aside from the energy-efficient design, the Rheem RTGH-95 offers continuous hot water with a built-in condensate neutralizer. Its LED lights indicate when the heating element is active or in standby mode, making it perfect for any sized home. Rheem is a leader in water heating for over a century. Its tankless water heaters are environmentally friendly and the perfect solution for any sized home. The Rheem RTGH-95 tankless water heater has been awarded the Best Green Product in Building Products Top 100 list, a list that recognizes the most innovative products for builders and homeowners. You can get a Rheem tankless gas water heater for a great discount at Westside Wholesale!

In the US, European and Japanese markets, tankless gas water heaters were very popular decades ago. While they’ve improved since then, they’re still expensive, need expensive stainless steel vents and produce hot exhaust, and have lower efficiency at short intervals. A gas tankless water heater can supply hot water to all faucets at once. A gas tankless water heater can also be connected in parallel to a standard electric water heater for more hot water.

Rinnai V Series He Water Heater

There are many benefits to choosing a Rinnai water heater. These units include a built-in recirculation pump and a 12 year heat exchanger warranty. They are available in two different models, one for natural gas and one for propane. Depending on the climate where you live, you can select between a 5 and 7.5 GPM unit. Read on to find out more. Weigh all the advantages and disadvantages of each one and decide which one best meets your needs.


The Rinnai V Series He is known for its low NOx emissions, which makes it a great option for homes with strict emissions laws. It can heat up to 9.4 GPM of water, and its advanced Circ-Logic technology ensures hot water availability in times of high demand. While this unit is not as efficient as a condensing tankless water heater, it’s still a very good choice for homeowners looking to save money on energy bills.


The Rinnai Control-R(tm) Wi-Fi Module comes with 5 feet of wire for connecting the water heater. This Wi-Fi-ready controller complies with California Energy Commission’s Title 24 standards. The Rinnai Tankless Water Heater should be installed in a central location, such as the mechanical room or basement. Installation can take place up to 300 feet away from the water heater. It is best to use 18 to 22 gauge wire to ensure strong Wi-Fi signals.

Isolation valves

Isolation valves are a vital part of your tankless water heater. They allow you to control water flow in different parts of the system. For instance, you can shut off water flow in the shower when using the shower head or turning on the faucet. An isolation valve works like a spigot under the sink that lets you control the flow of water. This way, you don’t need to bend down over the counter to turn off the faucet. Likewise, you can shut off the water flow in your system when performing maintenance or cleaning. Usually, the isolation valve is the same as the one found under the sink.

12-year warranty

Rinnai offers a 12-year limited warranty on its V Series He heaters. This warranty is valid in the U.S. and Canada. It can be extended to the buyer in the event that the product fails to function properly. The warranty covers the product and labor costs in case of repair or replacement. The warranty can also cover parts and labor costs if the unit is defective. The warranty can also be extended to residential applications, such as laundry and dishwashers.


The RINNAI V Series He tankless water heater is designed to provide ample hot water for showers and bathtubs. This product can be used for multiple applications, including laundry, dishwashers, and any other residential use. Its high efficiency allows it to deliver hot water quickly and easily to multiple destinations. You can expect to pay around $1600 for this unit before installation costs are factored in. However, you may wish to consider a different model if your water heater’s cost is more important than its performance.

Sensei Super technology

The Sensei Super is a Japanese technology that delivers 199,000 BTU of heating capacity, making it the most powerful residential gas tankless water heater available. Japanese engineering is known to be very reliable and the Sensei Super features a ten-year heat exchanger warranty. The Sensei Super also comes with top-of-the-line warranties. It comes with a ten-year heat exchanger warranty and is one of the most affordable natural gas tankless heaters on the market.

Noritz NR98-SVNG Natural Gas Tankless Water Heater

The Noritz NR98-SVNG is a natural gas tankless water heater for a home with up to four showers. The Noritz NR98-SVNG features commercial grade copper heat exchangers and is perfect for homes with a variety of water needs. It features built-in safety devices and an electronic service reminder to help ensure that it remains operating at peak efficiency. For maximum safety, this unit features a 12-year heat exchanger warranty.

Natural gas tankless water heater

The Noritz NR98-SVNG natural-gas tankless water heater is the best choice for homeowners who want to save space and money on heating their home water. It is available in two different sizes: a single unit and a double unit. Both models have the same heating capacity and are designed to provide hot water for multiple purposes. However, one of them is larger than the other.

The Noritz NR98-SVNG natural-gas tankless water heater is designed to provide 6.5 GPM of hot water and is perfect for mid-size homes that have three or more bathrooms. It is made of durable commercial-grade copper that is backed by a twelve-year heat exchanger warranty. It also includes features like a service reminder and adjustable height for high-altitude installations.

Built-in safety devices

The Noritz NR98-SVNG Residential Natural Gas Tankless Water Heater has built-in safety devices to protect you and your family. Unlike conventional heaters, Noritz models feature a Uniform Energy Factor (UEF) of 0.83, and the direct electronic ignition eliminates the need for pilot lights and other traditional safety devices. In addition, the tankless water heater has a flame sensor, overheat prevention device, and freeze protection device. In addition, the Noritz NR98-SVNG includes an easy-to-use remote controller. Built-in scale detection and auto shut-off are additional safety features.

Eccotemp 45H-NG Natural Gas Tankless Water Heater

This energy-efficient and quiet tankless water heater runs on natural gas. It is not recommended for installations above 5000 feet. It also is not suitable for floor heating or recirculation. If you’re interested in learning more about this unit, read on. Here are some important details. Using it properly is key to maintaining comfort and safety. Here are some of the things to look for before purchasing this heater. Let’s start with its installation instructions.

Outdoor Natural Gas Tankless Water Heater

The Eccotemp 45H-NG Outdoor Natural GAS Tankless Water Heater is a high-end outdoor model with a 6.8 GPM capacity. It is CSA certified and is easy to install. Its UL-listed, 3/4″ NPT fittings make it easy to install in your kitchen or bathroom. The 45H-NG is also EPA and CSA-certified and can handle up to two simultaneous hot water applications.

The Eccotemp 45H-NG Outdoor Natural GAS Tankless Water Heater is UL listed and is able to provide hot water in any size residential single-family home. Its low-flow, low-heat setting is ideal for most hot water heating needs. It features an anti-freeze protection system, an integrated digital display, and PCB. Its compact design and UL-certified power cord make it the perfect choice for smaller, tighter-spaced homes.

Energy efficient

The compact wall-mounted heater is equipped with a low-flow 0.8GPM gas modulating valve, a 110/120-volt UL-listed power cord, an internal exhaust fan, and Anti-Freeze protection. The fully automated control system ensures optimum performance. The 45H-NG is the best choice for larger-sized tiny homes. However, it does not support floor heating.

The Eccotemp 45H-NG is the largest indoor tankless water heater available. It provides up to 6.8 gallons per minute of hot water and 140,000 BTUs of heat per hour. Moreover, it can support two bathrooms. Since it is CSA-certified, the 45H-NG is suitable for homes with standard hot-water demands. It is available in both US and Canada versions.

Rinnai RU199iN Sensei

The Sensei RU199iN tankless gas water heater is a natural gas model that comes in a suitcase-sized design. It’s perfect for use in indoor locations and is easy to install. With 199,000 Btu’s at 92% efficiency, it can power up to 3 major uses at once. The ultra-small design and Wi-Fi compatibility make it easy to install in any space.

With its improved combustion system, the SENSEI tankless water heater provides an unending supply of hot liquid. In addition to the endless supply of hot water, it also features a space-saving design and environmentally-friendly features. The SENSEI series of Rinnai tankless gas water heaters have ENERGY STAR certification and can save up to 40% of energy over traditional tank models. The tankless technology allows for a 2″ vent run, which reduces the risk of a fire.

The SENSEI water heater is ideal for retrofits and new installs. It features the industry’s most versatile venting system. It can be vented using concentric, direct, or room air venting. Other features include an adjustable mounting plate, rotatable pressure relief valve, and a user-friendly control panel. You can easily adjust the temperature and other parameters from the comfort of your own home.

Great Alternatives

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How to Choose the Best Tankless Gas Water Heater

Best Tankless Gas Water Heater

The highest water heating capacity of the six tanks on our list is the Takagi T-H3-DV-N, with a capacity of 10 gallons per minute. It is suitable for use in both gas and electricity and is versatile enough for multiple applications. It can also handle up to four bathrooms, which is nice in colder climates. However, if you’re not in a particularly large household, this model is probably better suited for you.

In addition to saving water, a tankless gas water heater will also increase your home’s gas usage. You can program it to heat water only at certain times of the day, reducing your monthly utility bills. You can even use bypass valve assemblies in areas with hard water, which makes it easy to flush out deposits of calcium. This model is the best option for homes with hard water. But it is worth considering the additional costs.

A tankless gas water heater can be costly to install, but it’s much more economical than an inline unit. It can be installed in any room and is more affordable if your home uses natural gas. A tankless gas water heater can be installed in a crawl space. You should check reviews online and make sure that the plumber offers a written estimate. It’s also much more convenient than an inline unit.

There are several benefits to choosing a tankless gas water heater. Firstly, these units are smaller than standard models. They are designed to fit into a standard wall outlet and feature child safety locks and extra energy-saving modes. They are also safe to operate, and the thermostat can be programmed to turn off automatically if the need arises. It’s worth noting that the majority of tankless gas water heaters have a high price tag, so it’s important to make sure that you compare them carefully.

Another important consideration is how much space your unit requires. If you’re planning to install one in a closet or under the eaves, you’ll need a lot of space. If you don’t have a lot of space, you can choose a tankless water heater that is smaller and lighter than your existing unit. With this, you’ll be saving on gas, and saving money on electricity.

If you’re concerned about energy costs, a gas tankless water heater can be very cost-effective for large houses. Unlike traditional tanks, tankless systems can be plugged into an electrical outlet and are easily installed. They are designed to be safe for children and have extra energy-saving modes. They also have no pilot light. This can save you money and reduce your carbon footprint. They are much more convenient than inline heaters.

The best tankless gas water heaters have a high flow rate. At 9.8 gpm, they can heat water for a whole house or multiple bathrooms. Moreover, they can be used anywhere. A typical tankless gas water heater is only as efficient as its installation location. In contrast, a tankless system will save energy for the entire household. But a small home should not buy a large tankless gas unit.

When choosing a tankless gas water heater, consider its size and flow rate. You’ll need at least three gallons per minute for the shower and one gpm for the faucet. You should also consider its temperature-reduction features. A higher Energy Factor means that the unit will be more energy-efficient and reduce your utility bill. This is a good decision for homes with children. Those who are worried about the cost of the unit should consider purchasing one.

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