Our guides are backed by data and real world testing.
- Best Tankless Water Heaters: Compared
- Reviews of the Best Tankless Water Heaters
- Best Overall – Takagi T-KJr2-IN-NG Indoor Tankless Water Heater
- Budget Pick – MAREY Gas 10L Digital Panel Tankless Water Heater
- Best Outdoor – Takagi T-KJr2-OS-NG Outdoor Tankless Water Heater
- Best Value – Rheem RTG-84XLN 8.4 GPM Outdoor Tankless Natural Gas Water Heater
- Best Portable – Camplux 10L 2.64 GPM Outdoor Portable Propane
- Highest Flow – Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater
- Honorable Mentions
- Tankless Water Heater Comparison Table
- About Gas Tankless Water Heaters
- Is the best tankless water heater for everyone?
- Buying Guide: Best Tankless Water Heater
- Gas Tankless Water Heater vs Electric Water Heater, which is best?
- How to care for your Tankless Water Heater
If you’re looking for a way to save energy and cost each month, a tankless water heater can be a great investment. While the initial investment can be pricey (with installation costs considered), you will save money in the long-run compared to the cost of owning or renting a hot water tank.
This buying guide will cover gas powered tankless water heaters, which are suitable for providing hot water to multiple faucets in your home. We recently reviewed the best tankless electric water heaters, which might be a better choice if you’re trying to provide hot water to a single faucet.
This buying guide includes our expert tankless water heater reviews.
Best Tankless Water Heaters: Compared
Let’s take a look at the table below and see the products we’ll be reviewing.
Reviews of the Best Tankless Water Heaters
Best Overall – Takagi T-KJr2-IN-NG Indoor Tankless Water Heater
Features We Love
- Whopping 10 years warranty.
- 140,000 BTU.
- An impressive flow rate of 6.6 gallons.
- Optional conversion kit from NG to LP.
- Effortless installation
Tagaki T-KJr-IN-NG Indoor Tankless Water Heater is one of the two best tankless water heater units from Tagaki. Although small like it’s twin which we reviewed immediately below, it can meet the hot water demand of your home if you have two or three bathrooms.
It is very compact sized and measures just about 6.7 x 13.8 x 20.3 in. Tagaki equipped the unit with the ability to handle 140,000 BTU. This is in addition to the energy factor which hovers between 0.81 and 0.83 as the case may be.
The Tagaki T-KJr2 indoor tankless water heater is cost and energy efficient not forgetting that it’s eco-friendly. That notwithstanding, the unit must be installed by a Tagaki professional. DIY installations void the warranty on the unit.
This is probably a huge turn off considering the fact that one can save some money since they have prior knowledge. The installation is not difficult, although you may have to deal with venting and some other connections.
It has a TV10 conversion kit, although buying it is optional. This can be used to attach the unit to a direct vent unit in the garage.
As for the flow rate, it’s very impressive, to say the least. It has a maximum flow rate of 6.6 gallons per minute and has a BTU of 140,000 maximum.
Dealing with the ventilation can be a tough one for owners of this unit. You’d have to shell out some extra bucks to buy any fittings and other accessories that will be needed during installation.
Tagaki doesn’t ship the unit along with all the accessories you’ll need for installation. It does, however, include the basic ones that are vital. The installation manual is detailed properly to aid anyone installing the unit.
There is a 10-years warranty on it. The Tagaki indoor water heater doesn’t come cheap – it costs exactly the same as its other sibling.
Budget Pick – MAREY Gas 10L Digital Panel Tankless Water Heater
Features We Love
- Energy efficient.
- A good flow rate of 3.1 GPM.
- Digital display panel.
- 79,000 BTU.
- Electric pulse ignition.
- Works with either propane or liquid gas.
Our budget pick for this best tankless water heaters review is the Marey Gas 10L tankless water heater. It sports a digital panel which was lacking in our overall best model.
The most distinct features about this product are its low price, an impressive flow rate of 3.1 GPM, size, and energy efficiency. It can supply hot water to up to four showers and faucets all at the same time before the flow rate decreases.
Although the Marey 10L tankless water heater is a budget unit, it is energy efficient. Marey listed the energy efficiency of the unit as being between 54% and 87% – we didn’t verify the claims, however, the energy star rating is a good alibi for it.
The Marey 10L tankless water heater is designed to work with an electric ignition feature. Thus, no electricity is required since it draws its power from the gas line. Let us also mention that there are 2 batteries powering the unit.
Control knobs for the unit are situated in front of it. You can control the gas as well as temperature using the knobs.
There’s a 50ft distance to the point of use. This implies that this unit is suited for point of use purposes and as such, should be installed close to the point of use. In addition, installing it close to the point of use will significantly decrease lag time experienced.
One setback of this product lies with the ventilation. It does not have any venting mode, so you’d have to make the necessary arrangements for that.
Best Outdoor – Takagi T-KJr2-OS-NG Outdoor Tankless Water Heater
Features We Love
- Adequate minimum and maximum temperature.
- Dip switches for controlling temperature.
- Compact sized.
- 6.6 GPM flow rate.
- 140,000 BTU.
The Takagi outdoor tankless water heater is the twin of the indoor model which we chose as our best pick. They both share the same features which include a flow rate of 6.6 GPM, an energy factor of 0.82 as well as a BTU rating of 140,000.
Unlike the indoor model we reviewed above, this outdoor model is designed for external installation. This is to say that it is meant to be installed outside the home. Hence, you won’t need to vent the unit since it is already outside.
It comes with tons of features that allow it to work well even in the harsh conditions of the external walls of the house. There is a minimum temperature setting of about 122 degrees while the maximum sits at 140 degrees.
Although this unit is designed to be installed outside the home, only homes in a temperate climate are covered. So if you’re not living in a temperate climate, opt for the indoor version. This, however, is a major turn off for many people considering the fact that it is advertised as an outdoor unit.
Features We Love
- A fantastic flow rate of 8.4 GPM.
- Remote controlled.
- Comes with 10-feet thermostat wire
- 180,000 BTU
We picked the Rheem RTG tankless water heater as the most valuable tankless water heater. It is an embodiment of all you can ever want in a gas powered tankless water heater. However, it will cost you something to get and install this unit in your house.
Why do we like it?
First, the Rheem RTC tankless water heater is from a known brand in the industry. This was a major deciding factor as we had to look at the notable names and what people are saying about them. As for this unit, it has been 95% praises and a few complaints.
Secondly, the unit is well equipped to power a large household more than the overall best unit we reviewed earlier. It has a flow rate of 8.4 GPM – that is the flow rate of our budget and overall best picks combined together. Now, that’s massive power.
It is designed for outdoor installation and as such, will save costs associated with venting. Of course, it comes with all the necessary installation accessories to make installation easy. Rheem recommends getting a professional to handle the installation – we also recommend that considering the price of the unit. However, it is much easier to install than some of the other units on this review list.
One feature we love about the unit is the remote control. It’s not every day you get to see tankless water heaters that come with a remote control. The unit is pretty much responsive to the controls from its UMC-117 remote control.
Don’t bother looking for knobs or a digital display, as both are lacking. As for the BTU rating, the unit has a BTU rating pegged at 180,000.
Best Portable – Camplux 10L 2.64 GPM Outdoor Portable Propane
Features We Love
- Lightweight and portable.
- Low startup pressure.
- 2.64 GPM flow rate.
- Compact size.
Camplux 10L 2.64 GPM Ventfree Outdoor Portable Propane Tankless Water Heater is one of the newer models on the market. It is a very portable water heater with a 6L water pump. Arguably, it is one of the best deal you can get right now.
It is designed to deliver hot water with a maximum temperature of 114 degrees and a minimum of 46 degrees. It’s compact-sized and easy to install and control.
The Camplux water heater has one of the lowest pressure-startups in the market among many of the units we saw during this review. The startup pressure is about 2.5 psi. Another unique selling point of the unit is its portability. Given its small design, Camplux included a handle for easy carrying.
In terms of weight, the unit’s weight is barely noticeable – it’s really lightweight, to say the least. This makes it a good choice for people who go on camping often. You’ll, however, devise a means to deal with the weight of the gas tank which you’ll bring along.
Features We Love
- Straightforward installation procedure.
- 9.8 GPM flow rate.
- 0.93 energy factor.
- 199,000 BTU.
- Touch control buttons.
- Compact design.
Before we wrap up on this review of the best tankless water heater, let’s talk about the Rinnai RUC98iN tankless unit.
The first thing you’ll probably notice about it is the compact size and the fact that it is devoid of control knobs. Instead, it makes use of touch responsive buttons paired to a small digital display which was otherwise absent on the Rheem.
We love the touch control button. It was pretty responsive to touch inputs and changed the temperatures quickly.
Installing the unit is pretty expensive. Considering the fact that the unit itself is expensive, you may be spending almost the same as its cost price just to get it installed. The warranty won’t be voided if you self-install it, however, if you self-install it the wrong way, the warranty will be voided.
The unit has an energy factor of up to 0.96 as against the 0.83 we’ve seen on some models on this review list. In addition to that, it’s BTU is the highest – 199,000 to be exact.
Rinnai designed the unit to work with both PVC and concentric venting options, However, we recommend using metallic venting options as such will not get damaged easily in the long run.
The Rinnai tankless water heater has a flow rate of 9.8 GPM. This is by far the highest flow rate you’ll see in the market. Of course, it’s designed to power large households and can supply hot water to several points of use simultaneously. Thus, your daughter can take longer showers without ever running out of hot water. You’d only have to pay for more water.
There are other great tankless water heaters in the market that are worth considering, even if they didn’t make the #1 spot in their category. Check out some of our other recommended tankless water heaters below:
Tankless Water Heater Comparison Table
|Name||Our Rating||BTU||Flow Rate||Power Source||Type||Price|
|Takagi T-KJr2-IN-NG||5||140,000||6.6 GPM||Natural Gas||Indoor||Price not available|
|Marey Gas Digital Panel||4.9||79,000||3.1 GPM||Natural Gas||Indoor||$179.00|
|Rheem RTG-84XLN||4.8||180,000||8.4 GPM||Natural Gas||Outdoor||Price not available|
|Camplux 5L Outdoor Portable||4.9||34,000||1.32 GPM||Propane||Outdoor||$119.99|
|Takagi T-KJr2-OS-NG||4.8||140,000||6.6 GPM||Natural Gas||Outdoor||Price not available|
|Rinnai RUC98iN||4.7||199,000||9.8 GPM||Natural Gas||Indoor||$1,489.00|
About Gas Tankless Water Heaters
The gas tankless water heaters have been much around like their electric powered counterparts. There’s not much difference between both save for the fact that one is gas powered and the other, electrically powered.
Gas/propane tankless water heaters are believed to be much more powerful than the electric tankless water heaters. We, however, didn’t do any tests to compare the two. Two major things must be considered before going for gas/propane tankless water heaters.
- The first is to check if your gas supply is large enough to power the water heater.
- The second is to find a way to pass out the exhaust from the heat.
- Is the gas pipe long enough to reach the heater?
- What is the gas consumption rate of your home?
All of these will determine how much of the upgrades you will be needing to power your new gas tankless water heater. We explained these aforementioned factors and others in the buying guide below.
Is the best tankless water heater for everyone?
The answer is yes and no.
Yes: If you can afford the unit and the installation costs, please go ahead and install one for your self.
No: If you’re tight on a budget or you already have a means of getting hot water. However, you should have in mind that the benefits of installing the best tankless water heaters are endless in the long run.
Unlike the traditional water heater that can only contain a limited amount of water, a tankless water heater does not have any limited amount of water it can contain. So, every member of your family has uninterrupted access to hot water.
Buying Guide: Best Tankless Water Heater
Tankless water heaters are designed to provide unlimited hot water and also maximum energy savings. However, not all products termed tankless water heater can offer these features.
So, how do you know the one that is right for you then? Consider the following. You can read more on the factors to consider when buying a tankless water heater here.
Size of the Household
The first thing to look for when buying a tankless water heater is the size of your household. The bigger the size of your household, the higher the quality of the unit you’ll need.
If you have a large household, your hot water needs will definitely be much. Therefore, you need to get a unit that will supply hot water to everyone in the house.
Consider the price tag. A small household does not necessarily need a higher heater that is expensive. A small tankless heater will provide enough hot water for the whole house if all faucets are not turned on at the same time. Price varies according to models and functionality. The more powerful the heater is, the more costly it will be.
In addition, you need to consider the installation cost. The cost can be prohibitive or cheap – this depends on the manufacturer and the type of home you live in. For indoor heaters, ensure that proper venting is provided for it. This is one of the things that can significantly increase the cost of installation.
Again, some manufacturers insist on having their technician install the unit. If you do a DIY installation, you’ll void the warranty on your unit. Opt for a unit which doesn’t require professional installation.
Digital displays have become a standard feature in newer models of tankless water heaters. This helps in better monitoring and maintenance of the heater. It also helps you to keep an eye on the temperature of the water.
If you see a water heater with a warranty of more than 3 years, this is a good deal, grab it with both hands. Anything below that is not advisable, in our opinion.
There are two types of drainage valves namely; brass and plastic. The brass is more durable than the plastic. When buying a water heater, consider the ones that have a brass drainage valve.
This feature helps to prevent the water from freezing when the temperature is low. This feature is most common in the outdoor water heater models while some indoor models also have the feature. This is good for places with low temperature.
Safety features are a must when it comes to buying tankless water heaters. One of the most important safety features is the flame protection which helps in detecting issues whenever the heater is malfunctioning.
There is also oxygen depletion. Most newer models of tankless water heaters have these safety features except the cheap ones.
Some models of water heaters have showerhead capability whereby you can mount a showerhead to the water heater and take a bath directly. Anyways, this is not a common feature in most tankless water heaters.
Gas Tankless Water Heater vs Electric Water Heater, which is best?
The truth is there is no best choice between the two. They are both very good. If you’re looking to replace your existing unit, we suggest buying the same type. That is, if you have been using the gas type and you need a replacement, simply replace it with a gas tankless heater.
Switching from electric tankless water heater to gas tankless water heater or vice versa will require additional cost for fittings and installation. But, if you do not mind the cost, either of the two is best.
How to care for your Tankless Water Heater
Tankless water heaters tend to store up minerals after a long while. The minerals in water which cause its hardness are the sole culprits. We strongly advise installing a water softener as well as a whole house water filter in your home. This will greatly reduce the number of impurities in your water thus prolonging the lives of your appliances that use water.
To keep your tankless water heater in good shape, always flush it at least once every 6 months. It is not tasking to flush the heater although you’ll need to screw and unscrew. You can hire experts to do the flushing if you don’t want to get your hands dirty.
Here’s a video tutorial showing how to flush a tankless water heater.
Going tankless is a great decision. The units on we reviewed above are here because they met our criteria. Which would you go for – the gas or the electric tankless water heater?
Share your thoughts in the comment section below.
*last price update: 2019-12-10 - See Details