Best Commercial Tankless Water Heaters

Is It Worth Your Money?

Why buy tankless at all? What features and specs should I look for? Is it worth the cost?

These and other questions ran through my head when I started looking for a replacement for my old, busted tank. I’d heard of them, but nobody I knew had one. So I did some research (okay, a lot of research) and finally found the right one for me.

My plan here today is to save you some time and effort and break down some of the things I’ve found out, and best models I’ve come across.

Before we get to the list though, let’s go over some essential criteria, the five main things you need to know to make your purchase: Your workplace size, your usage, your location, the type of heating, and your price range. Then we’ll talk about the different kinds of units and their uses.


Rinnai C199

  • Compact design
  • Top Commercial Choice
  • Rock-solid reliable






Rinnai C199EN

Rinnai C199EN


  • 9.5 gallons per minute
  • 199,000 BTU

26 x 10 x 18.5 inches


Takagi T-KJr2-IN-NG

Takagi T-KJr2-IN-NG

  • 6.6 gallons per minute
  • 140,000 BTU

6.7 x 13.8 x 20.3 inches


Our Review of the Top Models on the Market

Rinnai RUR98iN

Rinnai is one of the big names these lines, and it’s easy to see why. Their Ultra Series is top of the line models. While a bit overkill for your average home, 9.8 GPM is plenty enough to get hot water to a whole building (if small enough) or an entire floor of a larger one.

It is a natural gas product, which would typically significantly decrease efficiency, but it being a condensing unit changes the game there. The RUR98iN boasts an impressive 96% efficiency rating, very nearly what an excellent electric product can achieve.

It also comes in a deceptively small package, only 10” x 12.5” x 26”. It may sound large considering other models with similar features are about 6 inches wider and sometimes longer and thicker as well. This means it can be easily stored in a small broom closet or similar tight spaces out of the way, perfect for any business’ needs.

In addition to a small storage profile, it also allows for a little venting profile, supporting concentric venting (both the intake and output pipes sharing space in the same vent) as well as standard PVC dual pipe venting, making installation somewhat manageable and less destructive to your property.

If you end up having to put it somewhere not easily reached, don’t worry. It has wifi capable temperature settings.

If something goes wrong, you can rest easy; this heater is warrantied for up to 5 years on the heat exchanger and other parts (12 years if you’re using it in the home) and a year on labor (with the option to double that time).

The main compromise here is the price. While not the most expensive model Rinnai sells, this bad boy will still cost you upwards of $2000 on Amazon. For this reason, it’s a model I feel is the best fit for businesses on either extreme of size; Particularly small establishments, like a law office or family-owned restaurant can use this to heat enough fluid for their whole business.

Large businesses, on the other hand, benefit from having one or more on each floor or for each bathroom, as a large office building or shopping mall will often have 4-6 sinks per room. It’s only the mid-size businesses that suffer here, as the expense is hard to justify for, say, three bathrooms with two washbasins each on three separate floors.

Stiebel Eltron Tempra Plus

It is a solid mid-range option, perfect for smaller businesses or larger ones. While it lacks the power of the Rinnai Ultra Series (clocking in at an effective 4.5 GPM), it is significantly cheaper, being an electrical product (and so is more economical to install) and its base price being under $800.

As a result, unlike the Rinnai, this one I feel is better suited to the low-mid end business, in particular set-ups like the previously mentioned three-floor building with 2-3 sinks per floor. The cost is low enough that you can comfortably buy and install 3-4 of these for the price of a single Rinnai.

The machine is noticeably smaller than the Rinnai as well, (at least when it comes to depth) at 14.52″ x 16.54″ x 4.61″ package. The much thinner size makes it easier to slide behind shelves and panels that bulkier units would never fit into. I’d caution against packing it too tight, however; unlike some models, it does not have remote or wifi controlled temperature settings.

With the lower price and size come a commensurate loss in raw power, however; Its GPM decreases significantly with colder water temperatures, and it only attains that 4.5 GPM if the water is already relatively warm. For those of us in warmer climates, this isn’t an issue (as the groundwater never gets below freezing), but places with harsh winters will want to stay away from this one.

All in all, this is an excellent purchase for those in temperate climates and on a budget. While it lacks many of the extra features some units have and its heating coil is relatively weak, it represents a good compromise between small Point of Use models and a whole building model.

Noritz NRC1111-DV-NG

This thing is a powerhouse! In terms of pure power, it tops the list. Coming in at an impressive 11.1 GPM, it will still only set you back about $1300. While it may lack many of the unique features of other products (like wifi or remote temperature control and different venting options), it makes up for it by just being an efficient, robust machine. Best of all, Noritz has confidence in their product; it has a lifetime manufacturer’s warranty.

Its only real flaw is its size, coming in much more significant than most other units on this list at 9.4” x 18.3” x 24.4”.

For my money, this is the best cost to effectiveness ratio on the market right now, which makes it perfect for commercial endeavors, particularly those with extremely high demands.

SioGreen IR260

This one? It’s just cool (well, hot). It heats without ever touching it, using infrared. Long story short: Quartz crystals heat up to around 200 degrees, and the heat rolls off them and into the fluid without ever even touching it.

And it does this with a 99% efficiency rating; almost no heat is lost. This heating method has another great benefit: maintenance is rarely needed since there are no coils to corrode or limescale buildup or algae to clean out. It’s also a slim package, at 20” x 14” x 6”.

Even better, this model is cheap, coming in at under $800. So what’s the catch?

Well, it’s not quite a Point of Use model, but it’s not the powerhouse of the Rinnai or Noritz either. It has a maximum output of 4.5 GPM in warmer climes, and 2.5 in colder ones. While I think the warm-ish weather performance is well worth the price, I’d stay away from this if you live somewhere the groundwater is below about 50 degrees.

Ecosmart ECO 18

I like this model; it’s the one I use in my office. It’s another mid-range model like the SioGreen, giving me about 3.5 GPM in the warmer weather we have here. I wouldn’t use this for a more significant office, but for my purposes (all I have are a bathroom sink, kitchen sink, small dishwasher, and a shower) it works great.

The main thing this model has going for it is it’s insanely cheap (under $500), and it works very well (a 99.8% efficiency is nothing to sneeze at)

Its profile is a slim 17″ x 14″ x 3.75″; I keep mine in a little broom closet with a vacuum and mop, and it even has the option for remote control temperature if you end up having to put it somewhere unwieldy.

I wholeheartedly recommend this for small offices like a law firm or a home office, though I’d steer clear for larger businesses; its price advantage is eliminated if you need to buy 4 or more of them.

Takagi T-H3-DV-N

The theme is safety, having more safety features than any other products on this list. It has notably low NOx emissions and safety cutoffs for both overheating and exhaust and temperature controls.

All that safety doesn’t sacrifice efficiency though, as it clocks in at 10 GPM and can maintain that flow to high temperatures.
The main issue here is it’s a loud, bulky machine. At 12.5” x 18.5” x 29.5” it’s the most massive machine on this list, and it outputs 55 dB of sound, about as much as a polite conversation. While that may not sound like much, it can be an irritating and distracting level of noise.

Still, at $1200 it’s a right price for power and peace of mind.


This one has a middle of the road performance in most aspects; 8.4 GPM, average size (27.5” x 18.5” x 9.75”), multiple venting options, etc.

Where it wins out, though, is the extra features. Mainly, it has excellent freeze protection (making it one of the few products that work great in cold climates) and the ability to sync multiple together for heavier duty needs quickly. At about $1100, that puts it in an excellent spot for mid-sized businesses in general, and anyone in cold climates.

Atmor Digital

Here’s another exciting Point of Use option. This one is notable because it’s cold water capable, rated at 2.45 GPM (enough for one sink or shower at a time) and able to heat the liquid as cold as 37 degrees to a comfortable temperature.

It comes in at a trim 13.375” x 17.375” x 5.25”; though I should note that’s only trim in general terms, relative to other PoU models, it’s a bit large. Still, at close to $300 it’s hard to beat on price. It’s one of the few smaller models able to handle the colder weather, and unlike the EcoSmart, it’s just cheaper than buying and installing multiple products. It isn’t going to break your wallet if you are in a small to a mid-size office building.

Takagi T-KJr2-IN-NG

Let’s look at one last mid-range option before we get to our winner. Of the ones in this price range (under $500), this is probably the best all-rounder. It has a respectable 6.6 GPM flow, and is the smallest model Takagi makes at 6.7” x 13.8” x 20.3”.

It is a non-condensing natural gas model. Its efficiency suffers (80% vs. the 98% of a condensing model), and its BTU output is a bit low for a commercial model (140k vs. an average of 199k). But even with that in mind, the performance of this model more than justifies the price. It outputs enough to service three low output sinks simultaneously, making it a great budget model for a mid-sized company.

Our Last But Best Model

Rinnai C199EN

While each of these models has their merits and uses, the Rinnai C199EN is the clear winner to me. The cost is a bit higher than most on this list, but its power and versatility blow everything else on the list out of the water. While it is overkill for many smaller businesses, I feel it has the best balance of power, cost, and features on the list (that last being where the Noritz falls short) and is useful in all climates, which is more than I can say for most of the list.

This one is commonly used in places like schools. Think of it sort of as somewhat budget version (around $1600, significantly cheaper) of the Rinnai Ultra. It has similar specs (9.7 GPM vs. 9.8) and is a bulky son of a gun (18.5” x 26” x10”). It even has the same wi-fi temperature control system.

The main difference here is heat. The C199ip reaches a much higher maximum temperature (185 degrees F) than the Ultra (140). What this means is that it can service a much more extensive area than almost any other heater on this list; less attention needs to be paid about how far from a given faucet the heater is.

With this, the option to just torque up the heat to serve a broader area becomes available (a feature it shares with the Noritz, primarily), and that makes it perfect for large buildings.

Side note: While I’ve chosen to spotlight the electric version here (as those are what I prefer where possible), this also does have a version fueled by propane for the same price; it’s up to your preference which to get as both have the same stats.

How to Choose The Right One

Your Household

Size, in this case, refers to both square footage and number of occupants. A small, family operated business is going to have different requirements than a sizeable multi-level office building. In the former case, you may even be able to get away with using a residential unit rather than a commercial one.

It is an essential factor to know for these products as well, but doubly true for a tankless heater. They heat the fluid as it comes through the pipes, meaning the farther away a given faucet is from the unit, the colder the liquid will come out.

Likewise, the more people using it at the same time, the more strained the unit will get. While it won’t run out like a tanked heater will, it will become unable to keep up with the strain and fluid will come out cold if it’s overtaxed. Depending on your business this may range from a minor inconvenience (in an office setting, people can technically make do washing their hands with cold liquid) or disastrous (in a restaurant… not so much).

Your Water Usage

While related to the above, this is a bit more nuanced. There’s one specification, in particular, you need to look at when purchasing a model: Gallons Per Minute (GPM). It is how much fluid the unit can heat per minute.

Commercial tankless water heaters hover at an average of 10 GPM, though some are slightly lower, and some are going significantly higher.

It ties neatly into knowing how many people are going to be working in the building because that in part determines how many different uses of hot fluid will be running at any given time.

For reference, the maximum output of a bathroom sink is 2.2 GPM (a shower comes in at 2.1), and dishwashers are around 1 GPM, so your average product can heat about four to five sinks at a time.

Remember to over-estimate your needs by a bit; while it’s unlikely that every sink or shower in the building will be in use at one time, it is a possibility you should be aware of and plan for.

While this may not seem that important to you, it’s essential when you plan on using two supply sources at the same time or one after another. You might need to take a shower and then wash a load of dishes, or you might have two family members who want to make a shower in the morning. A higher flow rate of 10 to 11 gallons per minute will keep your home and family with the necessary amount of H2o.

Your Location

This one is reasonably straightforward: Colder climates (and sometimes higher altitudes) make it harder to heat your supply.

Colder water is harder to heat in all units, but only the gas models are affected by altitude. Keep how harsh your winters are in mind when buying a product, and err towards a somewhat higher BTU (British Thermal Unit) output.

Type of Heating

There are two basics types: Electric and Natural Gas powered ones. Neither is it inherently better than another, though electric models tend to be better for residential use.

The main things you need to know:

Electric units are more efficient at heating the source (around 98% of the heat makes it into the liquid), are easier to install, require less maintenance, are cheaper on average both to purchase and install and are more environmentally friendly.

Given that ringing endorsement, you may ask: “What’s the point of a natural gas heater then?”

The answer: Natural gas units fare much, much better in colder weather. Though they have a 20% lower efficiency rating in warm weather, they have an easier time keeping up with demand in cold weather. While an electric one can stand to lose almost 2/3 of its efficient GPM in the cold, natural gas heaters run at nearly full effectiveness year round, and condensing units especially (that water vapor and “reuse” it, ensuring little heat is lost) are just as efficient as electric models year round.

It’s also worth noting that operation costs, in the short term, favor natural gas models (as natural gas is currently cheaper than electricity), but prices are estimated to rise in the near future.

Looking at the warranty will also reveal how much coverage you get. You may find that your warranty only covers parts one time and that any repairs needed in the future must come out of your pocket. It may cover the cost of any new parts but not include the installation of those parts too.

Your Price Range

Let’s get this out of the way first: they, on average, going to cost you more up front (starting at a minimum of the $1000 range). Not because the units themselves are more expensive (they’re usually roughly the same price for the average model) but because you need (I can’t stress this enough) a professional to install it.

You’re either dealing with an appliance that has very high voltages (240 volts) for an electric unit or needs to have proper, professionally installed ventilation (natural gas/propane). Neither should be placed by an amateur, particularly in the latter case.

But without further ado: The reviews.