What is the best tankless water heater? Read our exclusive guide to help you find the best tankless hot water heater for your needs. We’ll first talk about why and how to choose the right heater, and then follow that with a comparison guide & information on the best tankless water heaters for your particular situation.
Before we get started, on a personal note: I am the proud owner of a Rinnai 9.8 GPM Gas Tankless Heater, and I absolutely love it. It is the best tankless water heater for our needs, and it serves my family of 8 very nicely. We never, ever run out of hot water — and our gas bills have never been lower!
Even though tankless hot water heaters are fantastic, you may be unhappy if you choose the wrong model for your situation. Keep reading to find out how to choose the best tankless hot water heater for your needs.
If you’d prefer, you can also jump directly to the ratings.
Why choose a tankless water heater?
Tankless water heaters have many benefits:
Endless Hot Water: Never run out again!
Tankless water heaters provide endless amounts of hot water, which will make you very happy. You will never, ever run out of hot water.
No one enjoys running out of hot water! It always happens at the worst time. This will not happen with a tankless hot water heater!
Tankless heaters have no storage tank to run out of water. They don’t need a storage tank because they are capable of raising the cold water supply of your home up to a hot water temperature as the water flows through the unit.
Last Longer than a Conventional Water Heater
Conventional storage tank water heaters last, on average 10-15 years. Tankless water heaters have a life expectancy of 20 or more years.
You’ll need to buy (and send to the landfill) 1.5-2 conventional hot water heaters during the lifetime of one tankless hot water heater!
Energy Savings: $95 a year for a family of four
According to the US Department of Energy, tankless heaters can be between 8%-50% more efficient than a tank-style water heater, depending on your situation. Energy Star estimates that a typical family of four can save $95 or more each year with an Energy Star tankless water heater.
Let’s do a quick comparison of tankless vs. tank. Here’s the cost to own over 20 years for that family of four (keep in mind we need to buy 2 tank water heaters and only 1 tankless to cover this span of time):
| Tank | Tankless | |
| Up-Front Cost | $500 x 2 | $1,200 |
| Installation Cost | $1000 x 2 | $2,000 |
| Energy Savings | $0 | $1,900 |
| Total | $3,000 | $1,300 |
As you can see, a tankless hot water heater can be a very good investment. Of course, if you have teenagers that will now be taking 2 hour showers because the hot water never runs out, your mileage may vary. Your installation costs can also vary. However, most families will save a significant amount of money by going tankless, even with the higher up-front cost.
Free up space
You can free up the space of a small closet by switching from a tank to a tankless hot water heater. Indoor units can be easily mounted to your wall. Many units can also be installed outside, if you really want to free up space.
In terms of dollars, a tankless water heater can free up space equivalent to $300-$600.
Cleaner Air
Tankless water heaters keep your indoor air cleaner. Conventional storage tank gas water heaters backdraft carbon monoxide, nitrogen oxide, formaldehyde and other contaminants into your home. Tankless water heaters, like a high-efficiency furnace, have completely sealed combustion systems which keep your indoor air free of cancer causing compounds.
Tankless water heaters also reduce outdoor air pollution. They are so efficient and clean burning, outdoor pollutants are likewise diminished. If all residential gas tankless water heaters sold in the US were Energy Star certified, the emissions equal to 160,000 vehicles would be eliminated.
No Tank to Leak
Ever had a water heater tank leak? It’s a complete mess. At best, you’re just wasting a bit of water. At worst, there can be significant flooding and water damage! With a tankless water heater, there is no corroding tank, so leaks are highly unlikely.
Fresh Hot Water
Tankless hot water heaters provide fresh hot water! Consider this: hot water from a conventional tank-type system has been sitting in a corroding metal tank for hours, maybe days before you use it. It’s loaded with sediment and stagnant. Tankless hot water is always fresh.
Rebates
Your gas utility, electric utility, or local/state/province/federal government may offer rebates to offset the cost of an efficient tankless hot water heater. Check out our article on tankless water heater rebates for more information.
Why not choose a tankless water heater?
The primary reason not to choose a tankless water heater is that you don’t have the money to invest up-front to cover the installation and purchase.
Another reason may be that you’re not sure you plan to stay in your house for very long. In this case, you may not be able to recover the cost of a tankless water heater.
Lastly, many tankless heaters require periodic maintenance. It’s as simple as pumping a few gallons of vinegar through the unit, but if you don’t feel comfortable doing this yourself, you might lose some of the cost benefit if you have a professional come and perform the maintenance.
What is the best tankless water heater?
The best tankless hot water heater for you depends on your needs.
Whole house tankless hot water heater or point of use?
First, are you going for a whole house tankless water heater or point of use heaters? Whole house heaters are more typical in the United States and are the easiest retrofit for your home. Point of use hot water heaters can be nice (not only unlimited, but instant hot water), but also run off of electricity only and require electrical wiring to be present by every hot water outlet.
Electric or gas tankless water heater?
Second, are you looking for an electric or gas tankless heater? The easy choice is to go with what you already are using for hot water, though you might considering switching to gas if you can get it cheaply enough, or you might consider switching to electric if venting is an issue, or electricity is cheaper than your gas fuel source.
Here’s a comparison of gas and electric tankless water heaters:
| Gas Tankless | Electric Tankless | |
| Price (6 GPM unit) | ~$450 | ~$450 |
| Suitable climates | All | Warm |
| Maximum GPM (gallons/min) | 11 GPM | 6.6 GPM |
| Installation Considerations | May require new venting. May require upgraded gas connection (3/4″). | May require upgraded electrical service. |
| Service Life | Longer* | Long |
*There is disagreement of which type of water heater has a longer service life. One thing that is telling is that one manufacturer that produces both electric and gas tankless units offers a longer warranty on their gas units than their electric units, backing up their claim that gas units last longer.
How much hot water do you need?
Before you figure out what will be the best tankless water heater for you, you must determine how much hot water you’ll need to use at any one time.
Tankless water heaters are sized in GPM (Gallons Per Minute), so you must have some idea of the GPM you require.
To help you with this, think about the time when you’ll be using the most hot water, then add up the total GPM required using the chart below:
| Use | Approximate Flow Rate* |
| Bath Faucet | 1.0 GPM |
| Kitchen Faucet | 1.5 GPM |
| Dishwasher | 2.0 GPM |
| Washing Machine | 2.5 GPM |
| Shower | 2.0 GPM |
| Bathtub | 4.0 GPM |
*Please note that your usage rates may vary. These numbers are likely a good approximation, but may need to be adjusted. For instance, what if you have a “rain” shower head that uses 9 GPM? Or a energy saving shower head that uses 1.5 GPM? Well, then you’re going to need to calculate that separate from the chart above, which lists approximate usages only. You can adjust usage by adding aerators to your faucets and choosing low-flow shower heads.
How cold is your ground water?
You must understand the coldest temperature of your groundwater to understand what size tankless water heater is best for your application. Considering that tankless water heaters must immediately raise the temperature of your water to around 120° F, the colder the water is, the less hot water they can provide, because more energy must be applied to raise the temperature of the cold ground water.
This is called the “rise calculation” for tankless water heaters. It’s critical to know this, since the rated GPM of a tankless hot water heater is typically based on a low rise, that’s not realistic for most people, unless you live close to the equator.
For instance, consider the EcoSmart ECO 27 Electric Tankless Water Heater, and how its flow rate varies from 2.7GPM to 6.6GPM based on the inlet water temperature, and an output water temperature of 105° F. If you choose this unit and you’re expecting to run multiple showers and you live in northern Minnesota, you’re going to be sorely disappointed.
You can often run tankless hot water heaters in sequence to achieve the desired flow rates and temperature. It’s an option worth considering if you live in a cold climate and your demand exceeds your needs. Keep in mind that you can always start with one unit, and add another later if needed.
The map below provides information on average ground water temperatures, not the coldest. You should consider that the coldest temperatures could be colder than listed, all the way down to 33°F. To get the most accurate information on your coldest groundwater temperature, consider taking the temperature of your cold tap water, at various times during the winter after it has run for awhile. You can take the temperature using a standard instant-read meat thermometer.
What other features do you desire for your tankless heater?
- Indoor or outdoor?
- No venting is required for outdoor tankless units, but some may not be suitable for cold climates. If you live in the colder climate, and installing venting isn’t too much of a problem, consider an indoor unit. Outdoor units are rated for as cold as -30° F, but often must be specially installed with heat traced, insulated pipes, recessed boxes and drain systems to prevent water from remaining in the unit during cold weather. These extras add to the cost to install and run the unit. Generally, an indoor unit is a better choice for colder climates.
- Digital controls on the heater?
- Do you desire digital controls on the heater to set the temperature or set the status of the heater?
- Remote control?
- Want to adjust the hot water temp from afar? Consider a unit with a remote control. Some units include this as a standard feature.
- Recirculation capabilities?
- If your home plumbing is setup for recirculation, you’ll need a tankless unit that’s compatible.
- Energy rating?
- More efficient is better, but consider the up-front cost and your possible savings.
- Warranty?
- The longer the better. Most gas tankless come with a 12-15 year heat exchanger warranty, a 5-year warranty on parts and a 1-year warranty on labor. Be sure to get a free extended warranty by charging the purchase on a credit card that has automatic extended warranty protection, like the Costco Citibank Visa Card (extra 2 year warranty) or most American Express, Visa, MasterCard (extra 1 year warranty, check with your card issuer).
Here’s a video from Matt Risinger explaining some of the considerations when choosing a tankless unit:
The Best Tankless Water Heater
Below, we’ll highlight our best pick in each category of tankless hot water heater – along with several other good choices.
Use the following menu to jump to the section you are interested in:
| Energy Type | Indoor | Indoor | Outdoor | Outdoor |
| Natural Gas
|
Low Usage /Energy Miser
|
High Usage / Performance
|
Low Usage / Energy Miser
|
High Usage / Performance
|
| Propane
|
Low Usage / Energy Miser
|
High Usage / Performance
|
Low Usage / Energy Miser
|
High Usage / Performance
|
| Electric
|
Point of Use
|
Whole House
|
Point of Use
|
Whole House
|
* Shower icons represent an average number of showers for the category under average conditions. Be sure to review the specifics of your ground water temperature and the capabilities of the unit you choose to determine how many fixtures you can supply with a given heater.
Have questions about what type of unit to choose for your situation? Leave a comment at the end of this article and we’ll be happy to give all the help we can.
Gas Tankless Whole-House Hot Water Heaters Reviewed
Best Natural Gas Whole-House Water Heaters
Best indoor tankless natural gas for small families / low usage
The best indoor tankless natural gas hot water heater for small families is the Takagi T-KJr2-IN-NG.
Takagi has been a leading brand in tankless technology for years. They’ve been in the hot water business for 70 years. They are known for their excellent customer support and high-quality tankless heaters, which are designed and manufactured to precise standards in Japan.
Features:
- Endless hot water
- 6.6 GPM Maximum flow rate; 5.5 GPM @ 45° F
- 0.82 Energy Factor
- 140,000 Max BTUs
- 15-year heat exchanger warranty; 5-year parts warranty
- Includes remote control
- Venting with category III stainless steel, 4″ direct vent
- Complies with ultra-low NOx regulations
This heater is very similar to the Rinnai V65IN, and both would be excellent choices if these units will meet your household’s water demands. Going with whichever you can get a better deal on would be a good choice.
A budget pick worth considering is the Ecotemp i12-NG which may be a good choice in the following situations: use by singles, use in a cabin/cottage, retrofit of an existing small hot water tank. You may need to purchase low-flow shower heads & sink aerators if you choose this unit.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
Takagi T-KJr2-IN-NG Check Price on Amazon.com4.6 Rating |
$$ | 5.5 | 0.82 | 15-year heat exchanger, 5-year parts | Specs |
|
Rinnai V65IN
4.2 Rating |
$$ | 5.5 | 0.82 | 10 to 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Ecotemp i12-NG
4.4 Rating Budget Pick |
$ | 2.65 | 0.79 | 2 year labor and parts | Specs |
|
Rheem RTG-64DVLN
4.4 Rating |
$$$ | 5.6 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Noritz EZTR40-NG
5.0 Rating |
$$$$$ | 4.9 | 0.91 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best outdoor tankless natural gas for small families / low usage
The best outdoor tankless natural gas hot water heater for small families or low usage is the Takagi T-KJr2-OS-NG. This unit gets rave reviews from consumers and professionals alike for its reliability, and high flow rate for the price. With a 5.5 gallons/min flow rate at a 45° F temperature rise, and a price tag around $500, this is the best unit for the money.
Takagi has been in the hot water business for 70 years. They have good customer support and top-quality tankless heaters, which originate from Japan.
Features:
- Endless hot water
- Built-in freeze protection (however, proper installation is required to prevent freezing in your climate; you may need an indoor unit in colder climates)
- 6.6 GPM Maximum flow rate; 5.5 GPM @ 45° F
- 0.82 Energy Factor
- 140,000 Max BTUs
- 15-year heat exchanger warranty; 5-year parts warranty
- Includes remote control
- Complies with ultra-low NOx regulations
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Takagi T-KJr2-OS-NG
4.2 Rating |
$$ | 5.5 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
| Rinnai V53e-NG
4.4 Rating |
$$ | 4.5 | 0.82 | 10 to 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rheem RTG-64XLN
4.5 Rating |
$$$ | 5.6 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best indoor tankless natural gas for large families / high usage
The best indoor tankless natural gas hot water heater for large families or high usage situations is the Rinnai RUC98IN.
The Rinnai RUC98IN is a highly capable tankless hot-water heater, delivering one of the best flow-rates on the market (9.8 gallons/min max), and a remarkable level of efficiency (0.95). The units in the Rinnai RU series get excellent reviews on amazon.com and across the web. Rinnai is the most installed tankless brand in the United States due to their reliability. This means that plumbers know & love these Rinnai heaters.
Rinnai was founded in 1920. More than 30 million Rinnai Tankless Water Heaters have been installed worldwide. They boast a reputable support organization, and a long history of producing reliable hot water heating products. Rinnai is the #1 selling tankless water heating brand in the US and Canada due to their reputation for high-quality products and extensive marketing efforts. Their heaters are designed and manufactured in Japan to exacting standards.
This unit was my personal choice to serve my household of 8 people. I live in a very cold climate, and wanted to make sure I had adequate hot water despite my seasonally cold (38° F) groundwater. I was unsure about tankless water heaters when I chose this unit, but I knew that a tank unit would be unlikely to work for my household, as I had one previously and was always running out of hot water. As you’ll see below, I have no regrets.
I had heard all of the “issues” people bring up with tankless heaters: slow to get hot water, low flow rates, slow to kick on, cold water sandwiches, etc. Having used this unit for over a year, I can say that I have experienced none of these “issues”, and I am totally satisfied with this unit!
I did contact Rinnai customer support while setting up this unit, and they were very helpful in helping me understand how to best setup the unit for my particular needs. After getting things setup at first, I have not had to think about or touch the unit since!
Not only did I have a good personal experience with this unit, but consumers and professionals everywhere echo the praises of this particular tankless unit from Rinnai.
Features:
- Endless hot water, even in a household of 8 people
- 9.8 GPM Max Flow Rate (8.5GPM @ 45° F rise)
- Direct electric ignition
- Direct vent system with PVC/CPVC pipe for easy installation anywhere
- Sealed combustion to keep your indoor air healthy
- Front panel digital controls to set temperature and get information on the unit
- Ability to chain the unit with other units to achieve desired flow rates
If you have (or desire) a recirculating hot water system take a look at the Rinnai RUR98iN, which is the same as this model with recirculation capabilities built in.
If you don’t have the need for the hot water this unit provides, you might consider some of our other top picks (below).
| Natural Gas Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
|
Rinnai RUC98iN
5.0 Rating
|
$$$$$ | 8.5 | 0.95 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rinnai RUC80iN
5.0 Rating
|
$$$$ | 6.7 | 0.96 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rinnai RUC90iN
5.0 Rating
|
$$$$$ | 7.5 | 0.95 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Takagi T-D2-IN-NG
5.0 Rating |
$$$$ | 7.5 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Takagi T-H3-DV-N
4.4 Rating |
$$$$$ | 9.0 | 0.95 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Takagi T-H3J-DV-N
4.4 Rating |
$$$ | 6.6 | 0.95 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Takagi T-H3S-DV-N
4.4 Rating |
$$$$ | 7.5 | 0.95 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Rinnai RL75iN
4.3 Rating |
$$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rinnai V75iN
4.5 Rating |
$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Takagi T-K4-IN-KG
4.4 Rating |
$$$ | 6.5 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
Best outdoor tankless natural gas for big families / high usage
The best indoor outdoor natural gas hot water heater for large families or high usage situations is the Rinnai RU98eN, the sister model of the Rinnai RU98iN which you can read about in detail above.
Why is this the best?
- Very high output is great for large families
- Rinnai is a brand known for their reliability and quality
- Reviewers on amazon.com and elsewhere think highly of the units in the Rinnai RU line
- Plumbers recommend Rinnai: Rinnai is the number one tankless brand in the US
- Enhanced scale detection lessens possibility of serious, long-term damage to unit
Features:
- Endless hot water
- No venting required due to outdoor installation
- 199,000 Max BTU
- 9.8 GPM Max flow rate; 8.5 GPM @ 45° F
- 98F-140F Temperature Range
- Energy Star Qualified
- Works at high altitude: up to 10,200 ft
- Temperature lock function prevents accidental changes to water temperature
- 12-year warranty on heat exchanger, 5-year on parts, 1-year on labor, for residential use
- Ultra low NOx output
For other great options for outdoor tankless heaters, including fantastic offerings from Takagi, Rinnai and Rheem below. You might find that one of these alternatives is a better choice than our pick, if you need a lesser amount of hot water, or have easier access to those particular brands.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
|
Rinnai RU98eN
4.1 Rating |
$$$$$ | 8.5 | 0.95 | 12-year heat exchanger, 5-year parts, 1 year labor | Specs |
|
Takagi T-K4-OS-NG
4.5 Rating |
$$$ | 7.1 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Takagi T-D2-OS-NG
5.0 Rating |
$$$$ | 7.5 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
|
Rinnai RL94eN
4.1 Rating |
$$$$ | 7.2 | 0.82 | 12-year heat exchanger, 5-year parts, 1 year labor | Specs |
|
Rinnai RL75eN
4.3 Rating |
$$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rinnai V75eN
4.3 Rating |
$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rinnai RU80eN
5.0 Rating |
$$$$ | 6.5 | 0.96 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rheem RTG-84XLN
4.4 Rating |
$$$$ | 6.7 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
|
Rheem EcoSense ECOH200XLN ECO200XN3
5.0 Rating |
$$$$$ | 8.4 | .94 | 12-year heat exchanger, 5-year parts, 1-year labor |
Best Tankless Propane Whole-House Hot Water Heaters
Best indoor tankless propane for small families / low usage
The best indoor tankless propane water heater for small families is the Takagi T-KJr2-IN-LP.
Takagi is based in Japan and has been manufacturing hot water technology for 70 years.
Why is this one the best?
Among many other good choices, including the Rinnai V65IP, this unit stands out for these reasons:
- Takagi is experienced and has an excellent reputation for reliability & customer service
- Great value: this unit provides top flow rates (6.6 GPM) for the money
- Top reviews from consumers on amazon.com and across the web
- Unit includes a remote control, at no extra charge
Features:
- Endless hot water
- Complies with ultra-low NOx regulations in Texas and California
- 140,000 Max BTUs
- 15-year heat exchanger warranty; 5-year parts warranty
- Venting with category III stainless steel, 4″ direct vent
A value choice for extreme low usage situations is the Ecotemp i12-NG. It may may be a good choice in the following situations: tinyhouse, use by singles, use in a cabin/cottage. Calculate your GPM needs carefully if you choose this unit. If it works for you, it might work great. Keep in mind the reliability of this unit is likely to be nowhere near the Takagi, as evidenced by the difference in warranty.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Takagi T-KJr2-IN-LPCheck Price on Amazon.com4.5 Rating |
$$ | 5.5 | 0.82 | 15-year heat exchanger, 5-year parts | Specs |
|
Ecotemp i12-LP
4.4 Rating Budget Pick |
$ | 2.65 | 0.79 | 2 year labor and parts | Specs |
|
Rinnai V65IP
4.2 Rating |
$$$ | 5.5 | 0.82 | 10 to 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best outdoor tankless propane for small families / low usage
The best outdoor tankless propane hot water heater for small families or low usage is the Takagi T-KJr2-OS-LP.
When we look for “the best” hot water heater in a category, we look for a few different things:
- Brand reliability & reputation
- Warranty
- Flow rate
- Price
- How happy are people that buy these units
- How happy are plumbers with these units
In all of these categories, this Takagi unit excels: Takagi has an outstanding reputation; the warranty is best in the industry, the flow rates are outstanding for the price, and people and plumbers alike give this unit the best of reviews.
Features:
- Endless hot water
- 15-year heat exchanger warranty; 5-year parts warranty
- Built-in freeze, overheat, surge protection (however, proper installation is required to prevent freezing in your climate; you may need an indoor unit in colder climates)
- 6.6 GPM Maximum flow rate; 5.5 GPM @ 45° F
- 0.82 Energy Factor for Liquid Propane
- 140,000 Max BTUs
- Includes remote control
- Low NOx
- No venting required
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Takagi T-KJr2-OS-LP
4.5 Rating |
$$ | 5.5 | 0.82 | 15-year on heat exchanger, 5-year on parts | Specs |
| Rinnai V53e-LP
4.4 Rating |
$$ | 4.5 | 0.82 | 10 to 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai V65EP
4.8 Rating |
$$ | 5.5 | 0.82 | 10 to 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rheem RTG-64XLP
4.5 Rating |
$$ | 5.6 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best outdoor tankless propane for large families / high usage
Our top pick for best outdoor tankless propane heater is the Rinnai RUC98iP. See our review above of the Rinnai RUC98iN, the natural gas “sister” unit of this one for all the details about why this is the best unit for high demand. Other than the fuel burned (LP vs Natural Gas), these units are identical and a great choice for your hot water needs.
There are some worthy competitors in this category. The Takagi T-H3-DV-P matches up very favorably with the Rinnai and shares many of the same benefits. It does not get quite as high of a customer rating as the Rinnai, but it still gets a high customer rating. You might consider either this unit or the Rinnai for your situation.
Bosch and Rheem also make some very good units in this category that get high marks from consumers. You might also consider them as you comparison shop. See our table below for all of the top choices in this category:
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Rinnai RUC98iP
5.0 Rating
|
$$$$$ | 8.5 | 0.95 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Takagi T-H3-DV-P
4.4 Rating |
$$$$ | 9.0 | 0.95 | 15-year on heat exchanger, 5-year on parts | Specs |
| Bosch 830ES LP
4.7 Rating |
$$$$$ | 7.0 | 0.83 | 15-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RL94iP
4.3 Rating |
$$$$ | 7.2 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RUC80iP
5.0 Rating
|
$$$$ | 6.7 | 0.96 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RUC90iP
5.0 Rating
|
$$$$$ | 7.5 | 0.95 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai V75iP
5.0 Rating |
$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best outdoor tankless propane for big families / high usage
The best outdoor tankless propane heater is the Rinnai RU98eP. This unit is good for all the same reasons as the Rinnai RU98eN, which we reviewed above. Please refer to that review for all of the details. The only difference between that unit and this unit is the fuel burned, propane for the RU98eP and natural gas for the RU98eN.
Rinnai and Rheem dominate the category of outdoor tankless propane heaters. Other brands did not have highly reviewed models in this category.
The great thing about outdoor tankless units is that no venting is required, since the unit is already outside. The drawback is that you may need to consider their ability to withstand cold temperatures. Rheem suggests that their outdoor tankless heaters can withstand temperatures of -30° F, and Rinnai rates their outdoor heaters down to a temperature of -4° F (if protected from direct wind exposure). No matter which brand of outdoor tankless you choose, the pipes must be heat traced and insulated to provide freeze protection in colder climates. An optional drain-down system is also recommended for tankless outdoor heaters to allow water to drain out of the unit after use to prevent freezing.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Rinnai RU98eP
5.0 Rating |
$$$$$ | 8.5 | 0.93 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RU80eP
5.0 Rating |
$$$$ | 6.5 | 0.96 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RL94eP
5.0 Rating |
$$$$ | 7.2 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rinnai RL75eP
4.3 Rating |
$$$$ | 6.5 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rheem RTG-84XLP
Rheem RTG-84XP
4.4 Rating |
$$$ | 6.7 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
| Rheem RTG-95XLP
4.4 Rating |
$$$$ | 7.4 | 0.82 | 12-year heat exchanger, 5-year parts, 1-year labor | Specs |
Best Electric Tankless Whole-House Hot Water Heaters Reviewed
Our pick for the best electric tankless hot water heater is the Stiebel Eltron Tempra Plus line. They offer 6 different model sizes, in both a “regular” or “plus” version. All are fantastic choices for use as a whole-house tankless hot water heating system.
Why is the Stiebel Eltron Tempra Plus the best?
- Endless hot water
- Top-quality: German engineering & made in Germany
- Excellent reviews from consumers across the web for performance and reliability
- Advanced flow control in to ensure a steady output temperature with varying flow rates. No other electric tankless unit offers this.
- Silent operation
- 99% Efficient
Here’s some information on advanced flow control that these units offer. This feature is especially important for a whole-house electric unit, since you cannot get the flow out of this type of unit as you would out of a gas-fired whole-house tankless.
Refer to the sizing guide below for some guidance on what Tempra unit might be correct for your home.
Consider EcoSmart as a good alternative
Stiebel Eltron is not the only electric tankless heater to consider. You might also consider some offerings from EcoSmart. EcoSmart offers a lifetime parts warranty, and the units are extremely efficient. The ECO 36 can deliver slightly more water than the Tempra Plus 36 due to its slightly higher efficiency rating. EcoSmart units get a good reviews from consumers on amazon.com and Home Depot.
Avoid other brands
There are other brands of whole-house electric hot water heaters. Two big ones not on our list are Bosch & Rheem. Bosch is not on our list due to poor reviews from consumers, and Rheem’s whole-house offerings are too new to understand their real-world performance. We suggest staying away from these two brands in the “whole house electric” category.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| Stiebel Eltron Tempra 36 Plus
4.1 Rating |
$$$ | 5.46 | 99% | 7-year leakgage, 3-year parts | Specs |
| Stiebel Eltron Tempra 24 Plus
4.8 Rating |
$$$ | 2.75 | 99% | 7-year leakgage, 3-year parts | Specs |
| EcoSmart ECO 36
4.5 Rating Budget Pick |
$$ | 5.6 | 99.8% | Lifetime parts warranty | Specs & Sizing Guide |
| EcoSmart ECO 27
4.3 Rating Budget Pick |
$$ | 4.2 | 99.8% | Lifetime parts warranty | Specs & Sizing Guide |
Best Electric Tankless Point of Use Hot Water Heaters Reviewed
The best choice for an electric tankless point-of-use hot water heater is the iHeat Tankless series. This series comes in an attractive stainless steel casing, which will look great at your beach house, cottage, or wherever you choose to install this unit.
Here’s why the iHeat is tops in our ratings:
- Endless hot water
- Very good output ratings for the price
- Excellent reviews on Amazon.com and Home Depot from consumers
- 100% stainless steel heat exchangers to avoid corrosion
- Waterproof control pad
- Great for marine, beach or cabins
The whole-house tankless models above can also be used in point-of-use or near-point-of-use applications, so be sure to consider those as options.
The point of use electric choices from EcoSmart and Siebel Eltron are also strong contenders and worth considering. See below for full details.
| Model | Price | GPM @ 45F Rise | Energy Factor | Residential Warranty | Full Specifications |
| iHeat Tankless S-16
4.7 Rating |
$ | 2.42 | 99% | 5-year heat exchanger, 3-year parts warranty, 1-year heating elements | Specs |
| EcoSmart ECO 11
4.2 Rating |
$ | 1.8 | 99.8% | Lifetime part warranty | Specs & Sizing Guide |
| Stiebel Eltron DHC-E12
4.4 Rating |
$ | 1.75 | 99% | 3-year parts warranty | Specs |
Final notes
Have questions about what type of unit to choose for your situation? Leave a comment at the end of this article and we’ll be happy to give all the help we can.
Credits & Cautions
Refer to the manufacturer for full warranty details. Warranties can vary based on use, purchase location and installer.
GPM Numbers are estimated based on specs and standard flow rates. Please consult the specification or manufacturer for full information on flow rates under various conditions.
Installing your own hot water heater can be dangerous. It can be done yourself, but hiring a professional installer is recommended.
(photo credit: Roger Mammaerts under Creative Commons license)
Can the Eccotemp i12-LP be installed in a house in Canada?
Where in Canada?