Best natural gas tankless water heaters – A Buyer’s Guide
The pattern is always predictably the same. Standing “au naturel” in the shower, you’re staying just out of reach of the cold water. A tremble runs down your spine as you wait for the hot water. That’s quite enough, thank you. Tired of an ailing hot water system, an oldster that’s fitted with a slowpoke of a tank, you’ve made your choice. You’ve decided to actively research tankless water heaters.

From the off, the benefits are plain to see. Tankless hot water arrives instantly at your faucets and shower heads. Furthermore, these appliances are also known as on-demand heating systems, which means your shower will work its therapeutic magic when the need arises, not at all times of the day and night. In plain English, these technologically advanced appliances save money, yet they have more to offer than your old tank type water heater.

So, as thoughts of instant warm water and low utility bills sink in, take a few minutes to daydream about your next steamy hot shower. While you dream, the research continues. Let’s get started, for the results are imminent. Here, without further ado, pitched in this buyer’s guide, the reviews commence.
Outdoor natural gas
tankless water heater Indoor natural gas
tankless water heater

Shot Descriptions

Quick Comparison Table

Item model	Size, Weight, Usage	Max flow	Warranty
Takagi T-KJr2-IN-NG Check the price	6.7" x 13.8" x 20.3", 38 lbs, Indoor	6.6 GPM	10 year heat exchanger and 5 year parts
Rinnai V65IN 6.6 GPM Check the price	13.9 x 8.8" x 23.6", 49.8 lbs, Indoor	6.5 GPM	No data
Rheem RTG-84XLN Check the price	14" x 10" x 26", 54 lbs, Outdoor	8.4 GPM	No data
Takagi T-KJr2-OS-NG Check the price	6.7" x 13.8" x 20.5", 38 lbs, Outdoor	6.6 GPM	Residential: 12 year heat exchanger, 5 year parts and 1 year labor
Takagi T-H3-DV-N Check the price	11.2" x 17.8" x 24.9", 59 lbs, Indoor	10 GPM	No data
Rinnai RUC98iN Check the price	10" x 18.5" x 26", 82 lbs, Indoor	9.8 GPM	12 year heat exchanger and 5 year parts
Rinnai RL75iN Check the price	14" x 9.3" x 23" 65.9 lbs, Indoor	7.5 GPM	12-Year Warranty on Heat Exchanger, 5 Year Parts
Noritz NR981-SV-NG Check the price	17" x 13" x 29", 54 lbs, Indoor-Outdoor	9.8 GPM	No data
Bosch Greentherm C1050ES NG Check the price	11.2" x 17.9" x 30.5" 86 lbs, Indoor	10.5 GPM	3 - 15 Years depending on application
Noritz EZTR40-NG Check the price	27.2" x 18.3" x 9.4" 86 lbs, Indoor	6.6 GPM	12 years heat exchanger, 5 years parts, 1 year labor

Indoor natural gas tankless water heater

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas Every appliance reviewed in this extended guide sports conservative looks, except for the inlet and outlet valves and some kind of cleverly incorporated digital control panel. That being said, many under-the-hood differences exist. For example, the Takagi T-KJr2 is compact and energy efficient, it’s equipped with an energy factor that lays between 0.81 to 0.83, plus there’s a handy remote control included. Sit the remote on a coffee table, and never feel the need to seek it out when you need to raise the temperature by a few degrees.

Gas-fired, this is the smallest model in the Takagi range. The output rating promises a 150,000-BTU energy output and a 6.6-GPM max flow rate, which is enough to supply on-demand heated water to one, maybe two bathrooms or showers. Reliable by design, this model isn’t a suitable fit for larger homes.

The review opens with a budget-friendly low tariff tankless hot water heater. Purchase this model if you live in a small home or apartment, knowing it’s recommended as a built-to-last appliance. In point of fact, that last feature is supported by a 15-year warranty.
Pros and Cons

Rinnai V65IN 6.6 GPM Indoor Low NOx Tankless Water Heater Using the included energy factor rating as a benchmark, the Rinnai V65IN conjures up a respectable 0.82 energy factor. This overall energy efficiency reduces heat pump loading and lowers energy bills as it climbs higher. In other words, the higher the EF, the higher the efficiency rating. Taking this energy-oriented sweet spot into account, what other features make this unit stand out? Well, it has a small control panel mounted on the lower half of the front panel, plus it’s again fueled by Natural Gas.

Again, it’s compact, but that’s a common feature among tankless water heaters. This time around, the 150,000-BTU energy output and 6.6-GPM capacity suggest you’ll get the best out of this gas-fueled model if you install it in a mid-sized property, not a large family home. Aimed at small families, the Rinnai V65IN is a high-performance device.

Still in budget-friendly territory, this is a feature-rich gas waterless heater. Output and capacity ratings are satisfactorily high, then there’s an enhanced scale detection system, a temperature lock, and a leak detection function to tempt your itchy fingers to dip into your wallet.
Pros and Cons

Takagi T-H3-DV-N Condensing High-Efficiency Natural Gas Indoor Tankless Water Heater The price tag is first to grab your eye. The Takagi label is there, but the attached price is high, just high enough to make a budget-conscious buyer hesitate. Is that higher charge merited? Providing computerized safety features, Energy Star compliance, and rock-bottom LOx emissions, the answer is a confident yes. Sipping off of its natural gas fuel supply, the Takagi T-H3-DV-N also incorporates condensing prowess. Thanks to this steam distilling effect, the appliance is more efficient than many of its non-condensing peers.

The condensed steam eliminates energy losses while the ultra-low LOx feature adds peace of mind to the tankless water heaters operations. Finally, with an energy factor of 0.95 and a flow rate of 10-GPM, its Energy Star rating is a warranted power savings attribute.

More costly than some models, the condensing, energy-efficient design partners with a high output rating to make this recommended appliance a superior residential/commercial tankless water heater.
Pros and Cons

Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater There’s some sticker price shock to overcome here, but then the benefits kick in and push all concerns to the kerb. The Rinnai RUC98iN Ultra is a large silvery lozenge packed with energy saving
extras. Take note of the onboard condensate technology, a balanced byproducts compensation mechanism that improves system efficiency. Add to that a maximum BTU rating of 199,000 and a flow rate that peaks at 9.8-GPM, and you have a tankless hot water unit that delivers big on the performance front.

The indoor, natural gas RUC98iN merits its “Ultra” label. The Energy Star tag further underscores its ability to perform as an extremely efficient energy eater, one that’s on a diet thanks to the incorporated condenser tech.

For those who can afford to spend extra but want outstanding performance for their initial investment, the Rinnai RUC98iN Ultra delivers the goods. It’s efficient, compact, and built to instantly heat water in larger redidential and commercial properties.
Pros and Cons

Rinnai RL75iN Natural Gas Tankless Water Heater From up close, a spartan exterior suggests a lack of features. It’s not until you arrive at the digital controller that you realize you’ve underestimated the Rinnai RL75iN. The signature silver case is featureless, but that only means the capabilities of this tankless model are focused inside the MC-91-1US microcontroller. In addition to that smart electronic brain, the natural gas heating appliance has a 0.82 heating factor rating and Energy Star certification under the hood.

Built for medium-sized homes, the max 180,000-BTU, 7.5-GPM output power partners with natural gas consumption to better focus your product selecting wit. The optimized output and affordable fuel type also blends with a high-quality build to ensure uncompromising functionality. Other notable features include the ability to adjust the output to either commercial or domestic temperature baselines, a 12-year warranty, and a handy error code indicator. It is, however, a large device, and it needs a venting system.

The Rinnai brand carries some weight. On assessing the RL75iN, that hard-earned reputation has definitely been earned. Powerful enough to provide instant heat to two showering family members at the same time, the 0.82 energy factor rating keeps fuel consumption levels low.
Pros and Cons

Bosch Greentherm C1050ES NG Tankless Water Heater Your property’s real estate is precious, so it makes sense that it needs a premier heating solution. The Bosch Greentherm C1050ES is a top performing tankless water heater, with its temperature stabilizing feature really underscoring its superior build. Fed on natural gas, a quoted energy factor of 0.96 just serves to further reinforce this view. Expect ultra-efficient condensing operability, indoor and outdoor installation versatility, and embedded active bypass technology when you opt for this model.

If you’re seeking a system that offers a precise temperature control feature, you’ve found that equipment. If energy efficiency and Energy Star compliance are also part of your shopping list, then you’ve definitely arrived at the right product. Only, do realize that a premier build necessitates an equally premier price tag.

The Bosch label is familiar to every savvy consumer. Recommended on every level, the Bosch name assures energy efficient condensing action, super-precise temperature control, and a gift for supplemtal fluid filtration.
Pros and Cons

Noritz EZTR40-NG Indoor Tankless Water Heater Remaining in premium product territory, this last tankless water heater also sports the Noritz label. It features a system conversion kit, which means it arrives with everything you require to convert your 30-to-40 Gallon tanked system into a high-efficiency tankless setup. Relatively large and heavy, the expensive indoor appliance consumes natural gas, but the balanced fuel/output consumption system assures condensing functionality. In other words, this tankless water heater doesn’t exhaust large quantities of steam, so it’s even more efficient than other tankless appliances.

Easy to install, the Noritz EZ40-NG fittings exit the top of the compact box. Adding numbers to that ease-of-installation feature, the water heater is equipped with a 120,00-BTU max, a 6.6-GPM flow rate, and a fixed energy factor of 0.89. Translating those figures so that you can judge for yourself whether the device suits your property, the Noritz EZTR40-NG will instantly provide steamy hot water to two showers, although this figure drops slightly if you’re located in a cooler region.

Larger and heavier than most mid-range models in its class, the energy-efficient condensing feature more than makes up for that single drawback. Otherwise, the exceptional craftsmanship applied here combines with a superior build to position the EZTR40-NG solidly among other favorably reviewed tankless models.
Pros and Cons

Outdoor natural gas tankless water heater

Rheem RTG-84XLN 8.4 GPM Low NOx Outdoor Tankless Water Heater The low NOx costs a little more than your average tankless water heater, but it’s still considered a low-priced model. Let’s just say it’s at the top of the moderately priced scale. Considered a premium-budget appliance, where does the added value get passed along to? For one thing, it’s equipped with an 8.4-GPM capacity. Larger than many budget tankless units, the Rheem RTG-84XLN is obviously intended to heat water in larger homes.

Armed with an 180,000-BTU power rating and a remote control pad, the low NOx appliance housing must be mounted outdoors. Due to that feature, the housing is tough and built to defy the lelements.

At this point, the race is on to puncture the budget-priced ceiling. Easy to install, easier to use, the Rheem RTG-84XLN is recommended because it boasts a slew of useful features, including a mid-range capacity, a weather-sealed housing, and that ever-welcome Natural Gas (NG) fuel supply preference.
Pros and Cons

Noritz NR981-SV-NG Indoor-Outdoor Tankless Water Heater Indoor and outdoor capable, that degree of installation flexibility makes an immediate impression. Furthermore, the attractive polyester coated housing conceals a sturdy steel-plated frame. Inside the appliance, the coils radiate a coppery sheen. Then, when it comes to selecting the right appliance for the chosen environment, there are three slightly different venting options available. Simple to operate, the Noritz NR981-SV-NG natural gas water heater uses electronic ignition to make sure your hot water zips straight to your bathing destination.

By the numbers, the device features 199,900-BTU output and a 9.8-GPM flow rate. Tag a 0.88 energy factor rating onto the appliance, then add the realization that this energy-efficient box has enough output power to satisfy a large property. Do, however, realize there are three different venting system options. After that knowledge sinks in and you have the correct fitting on hand, choose whether the NR981-SV-NG is intended for indoor or outdoor mounting.

Loaded with safety features, there’s an embedded freeze protection and overheat protection mechanism built into the device. However, these features, plus the popular brand name, require a little more spending cash.
Pros and Cons

Takagi T-KJr2-OS-NG Outdoor Tankless Water Heater Moving outdoors again, this Takagi branded tankless water heater installs outside as a ventless small home appliance. In other words, it saves space and eliminates the obligatory venting mechanism by shifting its compact outlines into plain sight of Mother Nature. Because of that requirement, the device includes a capable freeze protection feature. Feeding off of natural gas, the Takagi T-KJr2-OS-NG is intended for use as a light residential water heating appliance.

Sporting a 0.82 Energy Factor and a 140,000-BTU, 6.6-GPM capacity, non-condensing technology keeps the outdoor variant of this Takagi-branded unit efficient, although it’s not quite efficient enough to earn an Energy Star award. Being that it’s installed on an outdoor wall, the local climate will impact its abilities. Expect two shower potency in warmer climates, but that two bathroom feature drops to a single shower or bathroom when it’s installed in a cooler region.

Granted, this model is ventless and built to function outside, so it’s designed to coexist with the harshest weather conditions. However, that same weather will impact the appliance’s output power. Still, the affordable Takagi T-KJr2-OS-NG is a recommended light residential usage device, with its low NOx qualities really underlining that endorsement.
Pros and Cons