
You’ve finally decided to go for a tankless water heater after hearing so much about them. The energy savings, the endless hot water and the small size all look really appealing.
But, the fear of buying the wrong unit is settling in.
You can’t really go wrong if you buy either, but when you stack up the differences in a Rinnai vs Rheem comparison, then you may find one of them suits what you’re looking for better.
Whether it is a question of budget, capacity, or efficiency, you’ll find one does better than the other in at least some categories.

Indoor
Natural Gas
9.8
★ ★ ★ ★ ★
$$$$

Indoor
Natural Gas
9.5
★ ★ ★ ★ ½
$$$$

Outdoor
Natural Gas
9.5
★ ★ ★ ★ ½
$$$½

Outdoor
Natural Gas
9.4
★ ★ ★ ★
$$$$
I’ll go through the major models of each and see how they stack up in a head to head match up.
In this article:
How to know what you need

Before you can know which tankless water heater you need, you have to evaluate what your needs actually are.
Here are the things you need to consider before you can decide which unit to buy:
Water Demand
Since a tankless water heater does not store any water, you need to calculate how much water you use at any one time.
This number is called GPM or Gallons Per Minute. It isn’t difficult to figure this out, but I have a handy chart below that will give you the average GPM of your household water fixtures to make it even easier.
Take a few days to write down when you have multiple fixtures running at once. See if this is a one off event or if you need these fixtures running simultaneously frequently.
- Shower – 1.5 GPM for low flow to 3.0 for standard
- Kitchen Faucet – 2 to 3 GPM
- Bathroom Sink – 0.5 to 1 GPM
- Dishwasher – 1.5 to 3 GPM
- Washing Machine – 2 to 3 GPM
- Bathtub – 4 to 6 GPM
It doesn’t matter if you use 100 gallons of water per day. It only matters how much you use at once.
When you have that number, then you’ll need to see what size tankless water heater you need for your GPM.
This is a bit more involved.
To understand how to determine what size tankless water heater you need, click that link to check out the full article with a handy calculator to figure it out!
Inside or Outside
You get a lot of options when it comes to where to install your tankless water heater. They offer up a lot of space savings since they take up so little space.
In addition to that, you can opt for an indoor or outdoor model to increase your possibilities further.
You should carefully consider where you would rather install your on demand water heater as you can’t just put an indoor model outside.
There are many reasons to go for an outside tankless water heater, but you’ll need to live in an area of the country where you don’t encounter too many days of freezing weather. Though many outside tankless water heaters have freeze protection, if it is consistently cold where you live, then that will impact how efficient your unit works.
To understand all the ins and outs of where and how to install a tankless water heater, check out this article that highlights the requirements that may impact your decision.

Fuel Source
For many people, this is not going to be an issue as they are free to choose from natural gas, propane or electric to heat the water.
Others, may have some limitations. I could say that Product X is the best one to buy, but if it only runs on natural gas and you don’t have any gas lines, then you need an electric model so this recommendation means nothing.
This is why I will review units in the same category so you can make a more informed decision.
The age of your house can also impact what kind of model you can buy because some older houses have small gas lines that aren’t compatible with a tankless water heater. This adds to the expense of installation and can negate any of the cost savings by switching to tankless from a tank system.
How much does it cost to install a tankless water heater? Click that link to read the full article as you may be surprised what you find.
Rinnai vs Rheem | An Overview
Both of these brands are really the best in the tankless water heater market. They both offer up exquisite engineering, great energy efficiency and lead the way in innovations in the technology behind tankless systems.
As I mentioned in the introduction, you can’t go wrong really with either brand unless you buy the wrong unit for your needs.
When you read negative reviews about any of the models that either produce, most of the negative ones were written by people who didn’t fully evaluate their needs and bought the wrong unit.
Keep that in mind as you read on.

Whole House Tankless Water Heater
Read More!
For the full review of the RUC98iN then click that link for the article with all the details!
Both of these models will cover your water demand for a whole house with a family of 5 or so. With almost 10 GPM you can be running multiple fixtures at once and not experience any slow down of water flow.
Here are some more details about how they compare.
Rinnai RUC98iN | Rheem RTGH-95DVLN | |
---|---|---|
Price | ✓ | |
GPM | ✓ | |
Warranty | ✓ | ✓ |
WiFi | ✓ | |
Efficiency | ✓ | ✓ |
Installation | ✓ | |
Condensing | ✓ | ✓ |
Other Features
Rinnai
- Has Wifi capability to connect your smartphone for things like setting the temperature and receiving maintenance alerts.
- A 12 year warranty on the heat exchanger is very generous and will give you the confidence that this will last you quite a long time. Long enough to pay for itself over the years.
Rheem
- With a built in condensate neutralizer, you don’t have to worry about adding one separately to deal with the acidic runoff or special drains.
- A self diagnostic system will alert you to any problems that may be affecting the unit and even let you know if there is a problem with installation.
Verdict
This is a very tough one to call. They both offer up very good GPM, but Rinnai beats out Rheem in this department.
If you are on a budget then I would say that the edge goes to Rheem since it costs less for the RTGH-95DVLN and it also costs less for installation.
If you like convenience, the Wifi capabilities of the Rinnai RUC98iN is really nice to have especially if you are running a smart home.
I give this one a push. You’re going to get a great tankless water heater whichever one you buy.
Outside Natural Gas Models
This is another close one as both of these outdoor tankless systems give you similar performance.
I think the decision as to which one will be better will come down to price as there is quite a difference between the two.
Rheem RTG-95XLN-1 | Rinnai RL94eN | |
---|---|---|
Price | ✓ | |
GPM | ✓ | ✓ |
Efficiency | ✓ | |
WiFi | ✓ | ✓ |
Installation | ✓ | ✓ |
Isolation Valves | ✓ |
Other Features
Rinnai
- With Circ Logic, you can set up a hot water recirculation that will keep hot water ready so you have instant hot water without needing to add a separate pump. It even can be programmed so it only heats the water in the line when you usually need it most to cut down on wasting energy.
- Included isolation valves save you a fair bit of money in two ways. One is that you don’t need to spend extra money to buy them separately and installed, and it also means you can do the yearly water flushing yourself so you don’t have to pay a plumber.
Rheem
- Installation potentially costs less due to the fact that it is compatible with ½ inch gas lines where Rinnai needs ¾ inch.
- There are no cold water sandwiches with the Rheem and you don’t even need to have a recirculation pump do keep the water heated since it has Hot Start programming so the heat exchanger stays ready to heat the water for a few moments after you’ve shut the water off. If you need to turn it right back on then you will have continuous hot water.
Verdict
Once again, you get two very high end water heaters here that both feature some nice technological advances for comfort and ease of use.
But, there is a difference in price. You pay a few hundred dollars more for the Rinnai up front. Though you do save in the long run if you plan to add isolation valves and a recirculation pump to the Rheem.
I would go for the Rinnai in this case since it is already for upgrades and maintenance without any headache in getting it set up.
Ways Rheem beats Rinnai
I’ll stop the comparisons there as the other models are two different from each other to put head to head.
What I mean by that is Rinnai doesn’t have electric tankless water heaters and Rheem has many.
Rheem has an entire lineup of electric tankless water heaters that go from small point of use ones for one or two fixtures, to being enough for a whole house. So you have more options with Rheem for your needs than you do with Rinnai.
You can see the whole line of Rheem electric tankless water heaters here to see if there is one that suits your needs!
The other major factor here is price. Rinnai make the most expensive tankless water heaters so you can save money with a Rheem.
Installation is also usually cheaper for a Rheem than Rinnai.
If you want to read more in depth reviews about Rheem products then follow the link!

Where Rinnai beats Rheem
For efficiency, capacity and performance, you can’t really find a better brand for tankless water heaters.
Yes, they cost more money than other brands in the same class, but what you get is reliable technology and more features. If you like bells and whistles like being able to connect to Alexa and having maintenance alerts sent right to your phone then you’ll love the Wifi.
You can add on other features like the recirculation pump that is already integrated.
You get the highest Gallons Per Minute (GPM) than with any other brands so if you live in a cold area or have a large family with high water demand, then you really need to have a Rinnai to meet your needs.
Read More!
You can read the full review of the RL75iN by clicking the link to see all the details on this popular tankless model.
Final Verdict
I think that Rinnai is the better brand between the two, but think that most people will get what they need with a Rheem and spend less money in the process.
The nice thing is that you get a high quality on demand water heater whichever brand you go with.
Do you have any questions about specific models not listed here? Then drop a line in the comment box below and I will get back to you ASAP!
2
- 2Shares
Hi,
as a homeowner, my biggest concern is maintenance after install. I would want to be able to do as much maintenance as possible without calling a plumber. I am fairly handy and can do most things myself and i plan on having a family member (Plumber) install the unit as I can’t seem to get a plumber to call me back for a paid install. So which is the easier unit to maintain and which is more reliable. In your opinion.
And can the Rheem be set up to maintain with some additions to plumbing?
and thanks for your support
Hi Joseph thanks for reaching out. As far as maintenance, pretty much all the gas fueled tankless water heaters are going to be about the same. The maintenance is really not that intense. You need to do a flush with either vinegar or Flow Aide once a year or so. It is very easy to do yourself without needing a plumber. With that in mind, the model that already has isolation valves, which are connections that allow you to run a flush liquid through the unit without having to detach the connections to the water supply, will be your best bet. The Rinnai RUC98iN comes with the valves and a pressure relief valves and will probably be your best bet. You can click the link to go to Amazon to get more details and the price but to me it is one of the best out there. You can also check out my article on how to maintain your tankless water heater so you can get an understanding of what you’re getting into when you buy one. Hint: Not much! Again, maintenance is very simple. https://yourh2home.com/tankless-water-heater-maintenance/ You should also think about a unit with wifi so you get maintenance alerts for one less thing to think about. Thanks again for the question and I hope this helps. Cheers Nick
I’m trying to decide between the Rinnai ru 160i and the Rheem 95dvnl-2 mdl. I have a 4 level home with five adults and one toddler two bathrooms and two dishwashers. I’m also trying to decide whether to rent unit or buy it outright. With either unit the installation would be provided at no charge. The rental for each is about the same but I’m not sure about purchase price.
Hi Kim. I would go with the Rinnai, myself. But, it really depends on what your peak water needs are. Have you calculated how many gallons per minute you need at its peak during the day? You get slightly less GPM with the Rinnai than the Rheem, but I like that model. Very interesting about the ability to rent. I had never heard about that but it is good to know that is an option. Let me know which one you go with and what you think! Thanks for reaching out.
What’s your view on Navien?
Hi Susan
I think Navien is a good brand, but they can be hard to find and they don’t have as many certified techs as Rinnai or Rheem as those two brands are more widespread than Navien. Do you have any specific questions about the Navien?
Which model of navien would you equate to the two models you wrote about? I’d be interested in cost comparison and gallons per minute.
I would say that the best Navien model is the NPE240S-NG as it has the highest GPM of any of the Navien gas models. It is difficult to find though. Do you already have a dealer that has them in stock?
Yes. We currently own a Navien and may need to replace it as it is over 10 years old. So we are weighing our options between staying with Navien or switching to one of the other tankless brands. How does the cost compare of the Navien model you mentioned to the Rheem or Rinnai?
The cost is hard to say as I don’t know where you can buy Navien these days in the US and Canada. But, the last I knew it was around $1300 on Amazon but they no longer carry Navien. If you want the same GPM for a good price then check out the Takagi T-H3-DV-N by clicking that link. You’ll save a few hundred and Takagi are also excellent.
Hello,
Deciding between the Rinnai RU199iN vs the Rheem RTGH 95DVLN-2. We have a family of 5 so both would likely meet our water needs. The Rinnia costs about $300 more. Thoughts? Which would you chose?
Thanks!
Hi Mark
If you need wifi or just an easier to control interface in general, then go with the Rinnai. If you don’t then I really think you’re getting a great tankless either way and won’t be disappointed. Personally, I have only had a Rinnai before and really liked it a lot, but if I were buying now, I would save the $300 seeing the state of the economy.
I know that doesn’t help haha.
Well, if you have more specific questions let me know. When you do buy one let me know which one you went for and what you think of it.
Cheers
Nick
I am interesting in buying the Rinnai V94 indoors gas water heater. We are a family of 4. The house has, 2 bathrooms and it is a 2500 sq fee house. Do you think this unit is good enough for our needs? Any downside of picking this unit vs the more expensive one if I don’t need all the bells and whistles?
Hi Javier. Forget about any bells and whistles and focus on the GPM and what your water demand is. I have another article about how to size a tankless water heater you should check out as it has a calculator so you can zero in on what size tankless you need. I think the Rinnai V94 will probably be good but you need to check your metrics first to know for sure. The thing is if you need more than 9.4 GPM then you only have a few choices as that is on the higher end of GPM. If you do the math and it looks like you will get enough water flow from the Rinnai I say go for it.
Here is the link to the article about how to size the tankless.
Hope that helps!
Nick
Hi there
Am doing a bathroom upgrade nithung fancy really just making it wheelchair accessible…
I’m trying to figure out what brand and even model I should be going for have no clue at all… we currently have low pressure water cylinder.. and in a 70’s home if that helps at all
Basically family of 2 adults and 4 adult children (ages 15-25) not reali kids but still living at home we have only 1 bathroom.. our busiest times of the day or usage is for about 1 hour when everyone’s getting home and general washing of dishes. No dishwasher.. your guidance would be much appreciated..
Hi thanks for reaching out.
So, to really zero in on the right model you need to do a little bit of math. It seems like even though you have high water demand with all the people in the house, it isn’t all happening at once, which helps. But, without knowing a couple of numbers I am afraid I can’t make a solid recommendation. You’ll need to know your temperature rise before you can accurately know how many GPM you need at the busiest times of day. You can figure this out easily by checking out my article on it with a calculator to help you figure out that number. https://yourh2home.com/sizing-tankless-water-heater/. You’ll need to know the temperature of the incoming water and then match that up against the highest GPM you’ll need during your highest water demand times. It is pretty simple. If you go there and read the article, then let me know what you get for a number and we can go from there.
Hope to hear back soon,
Nick
Trying to decide between Renai RUR160iN and Rheem RTGH-RH10DVLN. Which one ould be better in terms of performance and reliability? Also, which would need less maintenance or perhaps simpler DIY maintenance?
Thanks
Hi Someet
Either one that you get you will be happy with, but if I were to choose between the two then I would go with the Rinnai. Again, both are reliable and perform great, but I like Rinnai.