Top 7 Best Commercial Gas Tankless Water Heaters (December 2024)🥇

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Charlie W. Palmer

Water Systems Expert & Founder at Water Systems Guide

Hi! I'm Charlie. If you're wondering why I started WaterSystemsGuide, it's because I previously worked as a water systems specialist/consultant for a large government initiative in California, USA. However, after leaving, I wanted to provide advice and information for others, to pass my knowledge on, so I created this site!

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Last Updated: 21 December 2024

In this article, we’re going to be discussing the best commercial gas tankless hot water heaters that are available on the market.

✅Why use a gas tankless water heater for your business or organization

According to this study carried out by Consumer Reports, commercial tankless water heaters, including electric units, are an energy-efficient way of getting hot water. Their ability to process large amounts of water without storing it allows these models to consume 22% less energy than tank-carrying water heaters.

Their space-saving design is another notable feature of tankless heaters. Since they don’t have to use tanks to store water, these products can afford to be small and compact.

This is precisely the reason why you can install them in tight spaces with minimal fuss.

On top of everything else, these units justify their high initial asking price by delivering a constant supply of hot water. When a hot water tap is opened, an electric element or gas burner heats the water as it travels through the pipe. That means you won’t have to wait to get hot water at the tap.

💧Top Considerations Before Purchasing

• Technical Specs – We’ve done our very best to outline each heater’s technical specs, including thermal efficiency, flow rate (GPM), energy factor and temperature range, so you have all of this information available when making any comparisons between models.
• General Specs – We’ve also included information regarding the units physical dimensions and weight
  • Price – Price information has also been specified, with $ representing the lowest price and $$$$$ representing the highest. We realize that everyone has a unique budget, so this is an important consideration
  • Warranty – We’ve displayed warranty information where possible.
• Customer Reviews/Ratings – We’ve gone about researching only the highest quality tankless water heaters to include within this article, therefore you can be confident in knowing that any of these units are a great choice.

Commercial Gas Tankless Water Heaters Review – Top 7

Gas (Indoor Installation Only)

• Rinnai RUCS75iN Natural Gas Tankless Hot Water Heater – 5GPM – $$$$ – Skip to Product
• Rinnai RUCS75iP Propane Tankless Hot Water Heater – 7GPM – $$$$ – Skip to Product
• AO Smith ATI-540H-N Condensing Residential/Light Commercial Tankless Heater – 10GPM – $$$$ – Skip to Product

Gas (Ourdoor Installation Only)

• Rinnai V Series V94EN HE Tankless Hot Water Heater – 4GPM – $$$$ – Skip to Product
• Rinnai V Series V94EP HE Tankless Hot Water Heater – 8GPM – $$$$ – Skip to Product
• Rinnai RL94EP Tankless Water Heater – 4GPM – $$$$ – Skip to Product
• Rinnai RL94EN Tankless Water Heater – GPM – $$$$ – Skip to Product

Rinnai RUCS75iN Natural Gas Tankless Hot Water Heater

The Rinnai RUCS75iN Series SE tankless water heater is made for indoor installation only. It works best in a warm climate and in an area that is shielded from bad elements of weather. You can count on it to deliver the goods as long as it isn’t freezing out there.

Technical Specs

• BTU: 10,3000 – 160,000
• Thermal Efficiency: 99%
• Flow Rate (GPM): 5 GPM
• Energy Factor: 93
• Installation: Indoor Only

General Specs

• Price: $$$$
• Dimensions: 1 (D) x 31.1 (H) x 18.5 (W) inches
• Weight: 3 pounds
• Warranty: 12 year/5 year/1 year

Features

There are some models on the market whose unique selling point is their extreme efficiency. The RUCS75iN isn’t one of them. This unit’s huge flow-rate of 7.5 GPM is as impressive as its 0.93 energy factor. That means it delivers impressive money savings while also providing bucket-loads of hot water.

It is equipped with ThermaCirc360 technology that keeps on recirculating hot water through the pipes. This makes sure that you get the water the moment you open the tap. There won’t be any waiting time during which you have to do nothing but stare at the tap.

That this model has a compact design means you can install it in non-traditional spaces. It would quickly get under your attic, in the crawl space and even inside the closet. Also on offer is a compatible mobile app using which you can schedule timers and put the system into vacation mode.

Pros

• Huge flow rate
• 12 year residential/factory warranty
• Compatible with a mobile app

Cons

• Vent kit has to be purchased separately

Rinnai RUCS75iP Propane Tankless Hot Water Heater

Posing yourself as an alternative to one of the best-selling tankless water heaters is one thing. Justifying that claim is an altogether different ball game. That’s precisely what the iSpring RCB3P water filter system does. Though you’d have to pay over the odds to take advantage of what it has to offer.

 Technical Specs

• BTU: 10,300 – 160,000
• Thermal Efficiency: 93%
• Flow Rate (GPM): 7 GPM
• Energy Factor: 90
• Installation: Indoor Only

General Specs

• Price: $$$$
• Dimensions: 1 (D) x 31.1 (H) x 18.5 (W) inches
• Weight: 3 pounds
• Warranty: 12 year/5 year/1 year

Features

Wondering what is it that separates this model from the abovementioned Rinnai? Multiple features set apart the duo. This one runs on propane gas and is therefore recommended for those of you who live in far-flung areas where the supply of natural gas is impossible.

However, that doesn’t mean that you should ignore this model if you have a natural gas line coming to your home. That decision will deprive you of the extra 0.2 gallons per minute of hot water that this unit provides (7.7 GPM) vis-à-vis the RUCS75iN water heater.

Similar to its low-capacity counterpart, you can operate this model as well with a Control-R 2.0 mobile app. It features timers and schedules to help you pre-program this unit in advance. You can also activate a ‘vacation mode’ using the app that will put the heater to sleep.

Pros

• Endless supply of water heating
• Cinch to install
• Slim and compact

Cons

• Runs on propane

AO Smith ATI-540H-N Condensing Residential/Light Commercial Tankless Heater

Most tankless heaters you see on the market pay extra attention to their flow rate and efficiency. Some care about secondary things like ease of installation and all that. The AO Smith ATI-540H-N belongs to the minority that places equal emphasis on both.

Technical Specs

• BTU: 10,300 – 199,000
• Thermal Efficiency: 93%
• Flow Rate (GPM): 10 GPM
• Energy Factor: 95
• Installation: Indoor Only

General Specs

• Price: $$$$
• Dimensions: 5 x 18.5 x 29.5 inches
• Weight: 59 pound
• Warranty: 12 year/5 year/5 year

Features

Those of you who thought that its anonymous brand name would force this heater to come cheap are wrong. It is charging for its features and not the name on the package. Some of those features, like the overheat cutoff fuse, are what we come to expect from models costing this much.

Others, like the air-fuel ratio sensor that ensures optimum combustion and minimizes wastage of energy, are unexpected. Similar is the case with its exhaust safety valve that prevents the build-up of gases and the water temperature safety control that minimizes the chance of bursting of pipes.

Its flow rate of 10 gallons per minute is at least 2.5 GPM more than offered by any heater that we have seen thus far. Equally unprecedented is the 5-year warranty that this model gives on parts – as most heaters which cost this much lure their users with a lower, 3-year warranty.

Pros

• Air-fuel ratio sensor
• Overheat cutoff fuse
• Massive flow rate

Cons

• Have to wait for hot water

Rinnai V Series V94EN HE Tankless Hot Water Heater

One of the reasons why Rinnai is the most trusted brand in the tankless water heater market is its ability to produce high-quality indoor and outdoor heaters. This water heater is a proof of this statement as it has the construction to withstand everything Mother Nature can throw at it.

Technical Specs

• BTU: 10,3000 – 160,000
• Thermal Efficiency: 81%
• Flow Rate (GPM): 4 GPM
• Energy Factor: 81
• Installation: Outdoor Only

General Specs

• Price: $$$$
• Dimensions: 6 (D) x 24.3 (H) x 14.04 (W) inches
• Weight: 3 pounds
• Warranty: 10 year/5 year/1 year

Features

The Rinnai V Series HE Tankless hot water heater is designed for medium-to-large size enterprises. It offers a flow-rate of 9.4 GPM and lets you control its operation with a mobile app. You can use the application to schedule the heater’s operation, pre-program it and put it to sleep.

Some of you might not like this model using propane as its fuel. It is likely that others, particularly those that don’t have the facility of live natural gas, won’t care much about it. They would perhaps also appreciate the 120 months warranty that this model provides on its heat exchanger.

Pros

• 4 GPM flow rate
• Highly efficient
• 60 months parts warranty

Cons

• Not easy to install

Rinnai V Series V94EP HE Tankless Hot Water Heater

The fact that this hot water heater comes from as famous a brand as Rinnai comes across as a double-edged sword. On the one end, it means you would hear many people recommending it. On the other, its fame has allowed this heater’s manufacturer to inflate this model’s asking price.

Technical Specs

• BTU: 10,3000 – 199,000
• Thermal Efficiency: 82%
• Flow Rate (GPM): 8 GPM
• Energy Factor: 82
• Installation: Outdoor Only

General Specs

• Price: $$$$
• Dimensions: 6 (D) x 24.3 (H) x 14.04 (W) inches
• Weight: 3 pounds
• Warranty: 10 year/5 year/1 year

Features

Since both of them belong to the same V series, a comparison will inevitably arise between the V94EP and the V94EN that we reviewed above. This model scores a point on one count as its 9.4 GPM flow rate is at least 0.4GPM more than what is offered by its counterpart.

Aside from this subtle (but significant difference), you won’t notice both these models differing on many other counters. Both operate on the same fuel (propane gas), have exactly the same dimensions, and boast almost the same energy efficiency. So this model deserves your attention if you want extra water.

Pros

• 8 GPM flow rate
• 12 months’ labor warranty
• Can be used anywhere

Cons

• Unclear instructions

Rinnai RL94EP Tankless Water Heater

The Rinnai RL94EP is by far the most expensive tankless water heater on this review. Its price tag is so high that you could get two models of some of the electric tankless water heaters in this article at the price of one RL94EP. So does it justify its inflated asking price? Let’s find out.

Technical Specs

• BTU: 10,3000 – 199,000
• Thermal Efficiency: 82%
• Flow Rate (GPM): 4 GPM
• Energy Factor: 82
• Installation: Outdoor Only

General Specs

• Price: $$$$
• Dimensions: 6 (D) x 24.3 (H) x 14.04 (W) inches
• Weight: 3 pounds
• Warranty: 12 year/5 year/1 year

Features

One specific feature of this model that almost justified its astronomical asking price is its usage of Circ-Logic technology. This mode gives you the option to set the heater’s water recirculation patterns as per your habits. That ensures that you get hot water when you need it.

Aside from that, its usage of propane as heating fuel means you can as easily use this unit in the middle of a city as you could in a jungle. All you have to do is to carry a large-capacity propane tank that could allow this model to provide its maximum flow rate of 9.4 gallons per minute.

Pros

• Circ-Logic technology
• Up to 9.4 GPM flow rate
• Wi-Fi control

Cons

• Pricey

Rinnai RL94EN Tankless Water Heater

Is there anything different between this model and the one we reviewed immediately before it? Or are both of them the same with minor changes? To find out the answer to these questions, let’s review the Rinnai RL94EN tankless water heater

Technical Specs

• BTU: 10,3000 – 199,000
• Thermal Efficiency: 82%
• Flow Rate (GPM): 4 GPM
• Energy Factor: 82
• Installation: Outdoor Only

General Specs

• Price: $$$$
• Dimensions: 6 (D) x 24.3 (H) x 14.04 (W) inches
• Weight: 3 pounds
• Warranty: 12 year/5 year/1 year

Features

One count on which the RL94EN and RL94EP differs is visible from their name. The model we’re reviewing now operates on natural gas and is therefore recommended in city areas or other abodes where this facility is available. The RL94EP, meanwhile, relies on propane to heat water.

Apart from that major difference, there is not much to separate the two. Both are recommended for outdoor installation, are equipped with Circ-Logic technology, and boast a 9.4 GPM flow rate. The duo is also similar in its energy savings as both the heaters consume 40% less energy than tank heaters.

Pros

• Circ-Logic technology
• Up to 9.4 GPM flow rate
• Wi-Fi control

Cons

• Requires minimum flow rate of water to operate

Conclusion

It’s important to highlight that we realize everyone has different needs and requirements, alongside an entirely different budget. Therefore we try not to make solid recommendations, as we don’t know your unique requirements.

However, based on features, reviews, and price, we personally like the Rinnai RL94EP Gas Tankless Water Heater for those of you whose hot water requirements are huge. It delivers a huge flow rate of 9.8 GPM and comes with a respectable heat exchanger warranty of 12 years.

FAQs

🚰Is a gas tankless water heater worth it?

1.   Energy Efficiency

An estimate by the US Department of Energy explains how energy-efficient tankless water heaters are vis-à-vis their traditional tank-carrying counterparts.

Provided you have a small business that needs less than 41 gallons of hot water daily, a tankless commercial water heater will be 24% – 34% more energy-efficient than a conventional heater.

Even if your water heating requirements are enormous – up to 86 gallons per day – these units will still be 8% to 14% more energy efficient than their tank-carrying colleagues.

2.   Lower Utility bills

As we have already proved it beyond doubt that these units use less energy, you shouldn’t have any trouble believing the fact that these units can also lower your utility bills.

Energy Star estimates that tankless water heaters bearing its certification can save a household of four over $1800 over its lifetime, compared with any conventional tank-type heater.

The beneficial impact of these heaters isn’t related to household applications. That’s why the market of commercial tankless heaters is projected to grow at a rate of 7.5% per annum between 2019 and 2025.

3.   Extended lifespan

The absence of the tank not only empowers these units to deliver hot water on demand. It also enables them to last longer than tank-carrying water heaters.

Various estimates claim that with provided you maintain it regularly, you can count on your tankless heater to last five years longer than the tank water heater.

Provided you look after your model more carefully, it will outlast a similar-capacity tank-carrying model by over 10 years, with the overall shelf-life of tankless heaters rated at up to 20 years.

4.   Endless water heating

Do you know why the majority of their users refer to tankless gas water heaters as on-demand units? That’s because they deliver as much water as needed, when it is needed.

These units never run out of water because the water supply of your entire unit is the heater’s water supply. They don’t have any specific tank which they have to tap into to get their water.

As a result, with their built-in heating elements heating cold water as it passes through the pipes (and before it reaches your tap), you’ll get a constant supply of hot water.

5.   Space-saving design

Traditional tank-carrying heaters hold up to 60 gallons of water and therefore measure about 24 inches wide and 60 inches tall. That is the space they will consume in your premises.

In contrast, even the biggest capacity tankless water heaters measure 28 inches tall and 20 inches wide. This allows them to take up far less space in your indoors.

💧What size gas tankless hot water heater do I need?

To determine what size unit you’ll need, it’s useful to do the following steps, as outlined in the video below:

1. Determine the required flow rate in GPM
2. Determine the required temperature rise(Temperature Rise = Desired Output Temperature – Incoming Water Temperature)

Summary

Reviewer

Charlie W. Palmer

Review Date

Reviewed Item

Commercial Gas Tankless Water Heaters

Author Rating

5

Product Name

Commercial Gas Tankless Water Heaters