Best Tankless Water Heater: When it comes to hot water heaters, there really is no debate: everyone needs one, and it doesn’t matter where you live. Nothing beats a hot shower, right? We depend on hot water each day in our homes, from washing dishes to washing laundry, to baths. Hot water boilers make it all possible.
Now, when I say on demand hot water heaters, you’re probably envisioning one of those huge 7 feet tall metal tanks that essentially sits on top of a big gas range, constantly lighting up throughout the day to keep the water inside hot. That’s understandable, as these have been the conventional choice of most households for years.
However, have you ever run out of hot water in the middle of a shower? Or dealt with that cold blast of water because someone elsewhere in the house flushed a toilet, or decided to start a load of laundry? Of course, you have. Nobody enjoys that.
Looking for a point-of-use tankless hot water heater that doesn’t look terrible? The Atmor 24kw/24V ThermoPro is a perfect solution for those needing a reliable and capable water boiler they can install visibly in a bathroom or kitchen area, or simply the same location where their hot water tank used to be.
The ThermoPro is an electric unit that uses high-efficiency heating elements to create near-instant hot water in a variety of climates, using advanced sensors and flow control to ensure the temperature is always consistent, regardless of water output elsewhere
Temperatures can be controlled right on the front of the sleek-looking unit by using the chrome knob, allowing for adjustments in 1 degree increments — a rarity for nearly any hot water heater, regardless of type. The unit maxes out at 120 degrees Fahrenheit.
As with any tankless unit, the gallons per minute will depend on the inlet water temperature at that point of the year. The ThermoPro has a maximum of 4.6 GPMs when used with an inlet water temperature of 73 degrees Fahrenheit. Colder climates will attain a GPM capacity of around 2.5 to 3, which is still enough to run a shower and dishwasher at the same time.
The ThermoPro is definitely striving to be the best in the style department, but this little unit packs a punch in terms of heating ability. While it’s still better for warmer climates, it can still deliver adequate water amounts during winter months in colder climates. This is further improved by using it as a point-of-use installation, but that’s not required.
The ability to change heat settings by 1 degree is awesome, and the large dial makes things even easier. Furthermore, the unit is corrosion-proof and spill-proof, making it ideal for point-of-use installations where it will be exposed near the water fixture.
The only real potential drawbacks here revolve around the actual installation It can be a little trivy if you’re new to the process, and you’ll aso have to check quite a few different aspects of your home’s electrical setup to make sure you can support the unit.
At just under $400, the Atmor ThermoPro is an efficient and surprisingly powerful tankless hot water convector with a very modern aesthetic. The more decor-conscious buyers will certainly appreciate a unit that combines both form and function — and for a fair price.
What We Like
- Sleek look
- Easy temperature adjustments within 1 degree
- Low price for the power
Worth Knowing
- Complicated installation
- Requires higher inlet water temps for better efficiency
Tankless Gas Water Heater Reviews
Tankless on demand water heaters come in two distinct setups: gas, and electric. The majority of this list involves electric-powered models, but gas-powered versions are not to be overlooked. For many, this is actually a better option for homes with a conventional hot water boiler setup.
With that said, the Takagi tankless water heater T-Kjr2-IN-NG is one of many models in the company’s lineup, with this one being more of a mid-range model. But don’t let the size fool you. While this is a smaller, more compact version of larger Takagi models, this is also one of the most capable.
The T-Kjr2-IN-NG can be installed where your hot water tank used to be located, using the same gas connection. It’s larger than most electric units, but for a gas-powered model, it’s actually quite small, weighing just 38 pounds, and measuring 20x14x7 inches.
Water is heated as it passes through the unit by the way of gas-powered flames. Temperatures can range between 99 and 167 degrees Fahrenheit, depending on the ground temperature. Rather than using knobs, the T-Kjr2-IN-NG comes with a remote control to adjust temperatures as needed.
Thanks to its efficient design and gas power, the T-Kjr2-IN-NG can offer a GPM rate of up to 6, which is certainly more than most electric models in its range. In favorable conditions, it can supply hot water to homes with 2-3 bathrooms, allowing someone to shower, while the dishwasher is being run.
The T-Kjr2-IN-NG is a very feasible replacement solution for someone who wants to get rid of the tank and save on energy, yet not sacrifice on the amount of hot water they can immediately access without interruption or diminished temperature range.
The fact that is is so small provides advantages during installation, and for anyone with cramped space in their closet. I really like the use of a remote control as well. You don’t have to leave it sitting out if you’re worried about losing it, simply set it near the unit at all times and you’re fine.
As with any gas tankless boiler, you’ll need to properly ventilate the heat exhaust, so do keep that in mind. You also won’t get the same energy savings as an electric model, but it’s still a lot better than using a tank.
Overall, the Takagi T-Kjr2-IN-NG is probably the best gas water heater for the money. For just under $500, you can attain a very capable solution that provides a very high amount of gallons per minute, and at a fraction of the maintenance, replacement costs, and energy usage. This is a great unit.
What We Like
- High GPM
- Energy Efficient
- Small and Compact
- Remote control
Worth Knowing
- Requires Venting
- Installation is more extensive
The Noritz NRC98-DV-NG is a massive tankless gas water heater for buyers needing to meet high water output requirements for larger homes and families. Powered by gas, this is as close as you can get to a conventional tank water heater’s performance — only without the tank.
The NRC98-DV-NG accomplishes this in several ways, but mostly through two different heating elements that work together to create instantly hot water with a huge output level. The first element serves as a pre-heater in a way, while the second element actually uses the heat exhaust to further heat the water. Genius, right?
Not only does this make the unit more efficient and quicker at heating, it also minimizes the amount of heat exhaust, which is one of the main drawbacks of a gas-powered unit. With this design, the exhaust is around 100 degrees Fahrenheit, which is a lot cooler than other models.
The NRC98-DV-NG is definitely on the larger side, measuring 24x18x10 inches, and weighing 58 pounds. It has three main heat settings, but you can access 9 settings by purchasing a remote, also allowing you to adjust the temperature by 5 degree increments. Temperatures range between 100 and 140 degrees Fahrenheit.
As for the gallons per minute? The NRC98-DV-NG can maintain an output of 9.8 GPM with favorable inlet water conditions. This makes it suitable for a variety of climates. Yes, using it in cold climates will affect its output, but you can still get around 4-5 GPM, the max of many other units.
The NRC98-DV-NG also has a lot of safety settings, including a flame sensor, overheating prevention, and freeze protection.
And while the unit does it the 4 figure price range, it will eventually pay for itself anyway. It’s large size and exhaust setup is probably better with professional installation as well, so you’ll need to factor that in to your budget.
Simply put, the Noritz NRC98-DV-NG is the most powerful tankless on demand gas water heater on this list. If you’re looking for a high output model that can sustain standard temps and pressure for multiple bathrooms and fixtures at the same time, this is the way to go.
What We Like
- Very powerful with high flow rate
- Advanced safety settings
- Works well in cold climates
Worth Knowing
- Expensive
- Requires remote purchase to access more temperature settings
Propane Tankless Water Heater Reviews
For those looking for a tankless hot water heater that can really crank out a high amount of water, be it for home or commercial properties, the Rinnai RL75iN is definitely worthy of your attention. Another great example of a high output propane/gas-powered model, the RL75iN is up to task, and you don’t have to live in a warm climate to benefit.
The RL75iN is designed to take the place of your tank boiler in the spot it once occupied (or wherever you’d like to route gas lines.) And while it is a standard gas-powered unit, it does do things a little differently, mainly in being a high output model that can use natural gas or propane.
This unit can attain water temps anywhere from 98 to 140 degrees Fahrenheit, all of which can be controlled on the front of the unit with digital dials and readouts.It also offers error codes if something goes wrong so you know exactly what the issue is.
In terms of gallons per minute, the RL75iN can reach a whopping 7.5 GPM in ideal conditions, with a 5 GPM level in colder environments. This is all powered by anywhere from 10,300 to 180,000 BTUs, so this thing really is a beast.
If you have around 2-3 bathrooms in a moderate climate with cold winters, you won’t be lacking in hot water, even with two showers going at once. You can also convert the unit to a commercial model with a controller upgrade, reaching temps of 160 degrees. That’s hot.
The RL75iN comes with a giant 12 year warranty, with 5 years on parts, so it’s in it for the long haul. It’s one of the most powerful units on this list, and still manages to be Energy Star certified, which is hard to do, A scale detection system indicates when hard water is causing issue and requires a descaling cycle.
There are a few obvious drawbacks, mainly revolving around the price of the unit., but powerful models will always cost more for a reason. Ventilation can be tricky too, and you’ll need to make sure your gas line can offer enough pressure to reach 180,000 BTUs, so a reconfiguration my be needed.
As I’ve said, this is a massive unit that combines reliable water temps, versatility between fuel sources, ease of use, and built-in features that elongate the unit’s life. Rinnai RL75iN is the best propane tankless water heater and if a high GPM is your goal, the Rinnai RL75iN is worthy of your attention.
What We Like
- High GPM
- Energy Star Certified
- Awesome Warranty
- Scale Detection
Worth Knowing
- Large Size
- Expensive
- Venting may require a professional to assist
Gas and electric tankless hot water heaters are well represented on this list, as they should be, but propane-only units can be every bit as useful, and not only in RVs and small cabins/vacation houses. The Eccotemp FVI-12-LP is a great example of a versatile and easy-to-use tankless hot water heater that can be used in a variety of locations.
As i’ve said, the FVI-12-LP is powered by propane, and you can actually use anywhere from 20 pound to 100 pound tanks, giving you the ability to tailor your tank size for how much the unit will be used. It has a standard 2-prong plug-in that powers the ignitor.
The FVI-12-LP uses dials on the front to control the temperature, which is digitally displayed for better accuracy, taking out the guesswork. The maximum setting is 120 degrees Fahrenheit. When plugged in, the unit only activates the gas when it sense the water flowing through, so you save on gas there too.
The GPM can range from anywhere between .09 gallons per minute, and 4.8 when used in warmer climates. This makes it suitable for small homes with low simultaneous water usage. 3.0 GPMs is more average for this unit, which it can attain when being used with a 55 degree rise.
The small size and simple design of the FVI-12-LP makes it ideal for point-of-use applications, but it can also be used as a typical tank replacement in warmer climates, or homes that use one water fixture at a time.
With a price of under $275, the FVI-12-LP is one of the most affordable you’ll find, while still offering the capabilities of supplying a decent amount of hot water to sinks, showers, tubs, and more. Yes, you’ll still be purchasing propane from time to time, but not as much as you’d think due to the impressive efficiency of the unit.
The FVI-12-LP also comes with its own vent kit, and is relatively easy to install, making the process even simpler and more ideal for small homes and vacation cabins. No, it’s not as powerful as larger units, and not as suited for colder climates, but when used within its range, it offers excellent value.
Overall, the Eccotemp FVI-12-LP provides as much as it can for the price. The propane-powered nature of the unit gives it more versatility as to where you can use and/or install it, making it a logical choice for warmer locations and smaller homes with less-used water utilities.
What We Like
- Affordable
- Versatility due to propane power
- Easy to install
Worth Knowing
- Not very powerful in colder climates
- Still requires electric outlet
How a Tankless Hot Water Heater Works?
I’m sure most people are familiar with conventional hot water tanks. The concept for these is fairly simple: water is stored in a large metal tank, which is heated on the bottom by gas flames. When the tank is heated to the desired temperature, the water remains in the tank, ready to use.
As water is depleted from the tank, more cold water is fed into the tank, where it’s then heated as well before eventually making its way to faucets, showers, dishwashers, etc.
With a tankless water heater, the water has no way of being stored, so it needs to be heated as it passes through from the source, and into the home’s various water outlets.
This is done in several different ways, depending on the type of tankless hot water heater. Electric models use heat elements, while natural gas and propane versions use flames to heat the elements and piping the water passes through. (More on that in a moment.)
Benefits of a Tankless Hot Water Heater
So, why would someone even want to mess with a tankless hot water heater in the first place? Don’t water tank versions work well enough?
Perhaps, but water boilers without tanks offer some distinct advantages in more ways than one.
Energy Savings
Think about how a hot water tank works for a moment. In order to keep the gallons upon gallons of hot water hot, the gas has to activate frequently throughout the day whenever it sense the temperature has fallen below the desired heat setting, or if one simply uses a lot of hot water, be it for a bath, laundry, etc.
This constant on/off cycle uses up your gas, even when you aren’t actually using the water. Over time, that’s a lot of energy waste going on, and of course money being wasted too.
A tankless version only uses heat and energy when it’s activated, and then shuts off right after. There’s no meaningless heating of water throughout the day, simply to keep a giant tank of water hot enough just in case you decide to use hot water at any given moment.
Endless Hot Water
Ever run out of hot water in the middle of taking a shower? Your hot water tank was too depleted to keep supplying hot water, probably due to either someone else taking a long shower or bath before you, or doing a few loads of laundry during your bath.
When using a tank, you are always operating with a finite amount of water. These heaters heat as the water enters and comes to your fixture or appliance, so you never have to worry about running out. You could leave the shower on all day long, and you’d still never run out.
For some households with lots of kids or roommates, this is an invaluable advantage that can certainly help things go smoother in the mornings.
Avoids Catastrophic Messes
Most of us know someone that’s had a hot water tank fail at some point in life. More often than not, this leads to the tank leaking countless gallons of water into the home, ruining hardwood floors carpet, and more. It can be an event that ends up costing a homeowner thousands of dollars.
While proper care and maintenance can help avoid this, when you’re dealing with a huge tank of water sitting inside a closet or utility area, it’s always a risk.
Tankless hot water heaters don’t store water, so there’s nothing to spill or leak.
Improves Home Value
Tankless systems are environmentally friendly, and have a sort of modern allure that is appealing to many prospective buyers. Installing these water heaters in your home can instantly boost your home’s value, and make it appear more attractive to buyers.
Types of Tankless Hot Water Heaters
A popular type for those going for a replacement that will have little to no drop-off from a hot water tank, natural gas tankless water heaters use the game gas lines your conventional tank heater uses.
The unit is installed into the gas line, often in the same hot water closet. The water is then fed into the unit, which triggers the ignition that lights the flame, which then heats the water as it passes through.
Natural gas units do require venting, which requires a lot of extra work beyond just installing the unit in the home. Vents can run horizontal or vertical, depending on your home.
Natural gas water heaters are usually the most powerful, provide seemingly instant hot water, and offer a higher flow rate of hot water. However, they are not as energy efficient as electric models.
Electric
Electric tankless hot water heaters are completely gas-less, and rely on electrical heating elements that heat the water as it moves through the unit.
Since these don’t require gas, they are easier to install, and also do not require any ventilation.
In terms of energy efficiency, electric water heaters are easily the best, and can offer the most savings on your bills. However, they are typically not as powerful as gas models, and may take a little longer to get the hot water flowing.
Propane
Propane tankless heaters operate just like natural gas models, but have the ability to hook up propane tanks instead of being slaves to gas lines. Some models are compatible with both natural gas lines and propane tanks.
Using propane allows the boiler unit to be installed anywhere, rather than where the gas connection is. Many portable models use propane, and also some smaller ones for homes with little water use.
Whole Home vs. Point-of-Use
One key difference to be aware of with tankless units is whole home and point-of-use versions.
As the name suggests, whole-home units operate like a tank heater, installed in the main location that equally serves all water lines in the home simultaneously.
Point-of-use units are meant to be installed into the water line of a particular fixture. This most often involves a sink but can be installed into a shower water line. These units supply hot water directly to that particular fixture, which usually makes them very efficient with a high flow rate.
Terms to Know
In order to comprehend some of the main words used in describing the features and specs of these tankless water heaters, here are some quick definitions to get familiar with.
Flow Rate
This refers to the amount of water a hot water boiler can provide, both maximum and minimum. This is measured in gallons per minute (GPM.) The maximum GPM is what the unit can put out in ideal conditions, while the minimum is the amount of water required to trigger the system into turning on and heating the water.
Inlet Water Temperature
Inlet water temperature is the temperature of the water coming into your home and inside the unit, prior to being heated. This has a significant effect on your flow rate, and the temperature range of your water as well.
Inlet water temperatures change throughout the year, depending on where you live. When the inlet water is colder, your hot water heater has to work harder to quickly convert the cold water to the desired temperature, which may reduce flow rate.
Temperature Rise
Sometimes when reading about a particular unit, you’ll see the information refer to what’s known as a temperature rise. This figure is the difference between what you have the water heater set at, and what the inlet water temperature is.
For example, if the inlet water temperature is 65 degrees, and you have your water heater set at 110 degrees, the temperature rise is 45 degrees. Manufacturers will often list what the flow rate is in relation to the temperature rise, such as: “3.5 GPM when there’s a temperature rise of 40 degrees.”
Larger temperature rises often result in lower flow rates.
What to Look For When Choosing a Tankless Hot Water Heater?
Thinking about buying a tankless water heater? Make sure you go over these aspects first.
Power Source
The power source of the unit will determine how well it works, and where you can install it in the first place.
Natural gas units will need to be patched in to your gas line, which is almost always where your water tank was prior. There are always exceptions to this, but also keep in mind that you’ll need to install ventilation as well.
Electric models can be installed practically anywhere, as long as there is a power outlet nearby.
Propane models can be installed most anywhere too, but they almost always need a power outlet for the ignitor, and usually require ventilation as well, but not always.
Gallons Per Minute/Flow Rate
This is incredibly important, as this indicates the overall level of performance you have available, which in turn determines how many water fixtures and/or appliances you can use in your home at the same time, without experiencing diminished water pressure or water temperature drops.
Here are some estimates for how much water you’ll use for each application:
- One sink or shower – 1.5 GPM
- One shower and one sink simultaneously – 4.0 GPM
- Two showers simultaneously – 5.5 GPM
- Some like to discuss GPM in relation to a home’s size, but this isn’t always accurate. The GPM is more in relation to how many water applications you can use at once.
So, if you have a larger family, and don’t want to have to worry about running a dishwasher while someone is showering, a GPM of 4+ is where you should be looking. If you live alone, or with one other person, you can often get by with a GPM below 3.
*Water-saving shower heads are a great way to get more out of your water heater, as they restrict flow while maximizing water pressure, enabling you to have higher water pressures while using less gallons per minute.
I recommend you purchase one of these shower heads for each shower in your home, regardless of your water heater’s GPM.
*Keep in mind that those living in colder climates will need a higher GPM to cover the temperature rise gap.
Size
Tankless water heaters are always smaller than actual water tanks, but the size is still important if you are trying to get a good fit in the space you’ve chosen to install it. Larger heaters usually it where you previously housed the water tank, such as a closet or laundry room, but point-of-use models can be harder to fit when being placed behind a sink or shower.
Make sure you measure the space and compare it to the unit you’re considering before purchase.
Conclusion
As you can see, tankless hot water on demand heaters are really not all that complicated, you just need to know what to look for, and what your water needs are going to be. Hopefully you now have confidence with your buying decisions as well.
These 10 products all vary from each other in many ways, but the diversity I covered was intentional, making sure to touch on a wide range of different budgets, flow rates, heat sources, and size.
Make sure you double check the specs in relation to your home’s needs, and of course the space you’ll be installing the unit in. After ordering the best tankless water heater of your choice, and completing the installation, you can immediately get to enjoying an endless supply of hot water on demand, saving on energy costs in the process. Good luck!