So here you are, looking into tankless water heaters. You probably already know that they will save you a significant amount of money on your utility bills over the long term (potentially one-third per month less), and you also know that they have the potential to provide unlimited hot water––no more being limited to the size of your tank. If you haven’t completely been convinced of this, you can read on the pros and cons of tankless water heaters.
But as tankless heaters have grown more popular, with more and more models available, making the best choice for you has gotten harder.
Well you’re in the right place! We’ve done the research, and have four water heaters to recommend, including best sellers, best value, and best medium and high demand. Because you pay more upfront for tankless heaters, you need to make sure you pick the one that will meet your specific needs, without going over your budget. Whether you live alone or in a big house with a lot of folks, one of these heaters will be the right one for you.
Best Tankless Water Heater Reviews
Best Seller – Rheem RTE 13 Electric Tankless Water Heater, 4 GPM
The Rheem RTE 13 is far and away the most popular tankless water heater on Amazon, because it has a maximum flow rate of 4 gallons per minute (GPM), which for the price is quite a lot. An ideal choice for a one-shower-at-a-time household, and if you are equipped with 1.5 GPM low flow showerheads, you could try running two at a time. Previous buyers said this one could pay for itself in less than two years! Plus, it’s super compact and convenient, so you can install it in cabinetry, or hidden under the sink!
Reviewers say that number might not live up to expectations in cold climates, especially in larger households. This one is a terrific choice if you live alone, and should similarly work well for couples/roommates in one bathroom apartments.
The obvious advantage for this heater is the price, which is pretty unbeatable. As the reviewer noted above, it’s extremely small, which again would be an advantage for people living alone or in single-bathroom households. Since it is an electric heater, it will cost less upfront to install, and if it lasts even only a year and a half, it will pay for itself.
The flipside of being a small unit means that it is not the most powerful. Without low flow showerheads, two simultaneous showers is out of the question, and given that the 4 GPM flow rate is a maximum, the performance might not live up to expectations beyond single hot water use at a time. Not an ideal unit for larger households (more than, say, three people), and definitely not a unit for the coldest climates.
By far the cheapest unit with a large flow rate for the price, the RTE 13 is a great choice for small households and apartments, and could even be made to work in larger households willing to do one thing requiring hot water at a time. Just don’t expect it to thrive if you push it to the limit (i.e., simultaneous showers, cold climates). It’s probably worth taking the 4 GPM claim with a grain of salt, because it is worth overestimating your flow rate to ensure proper performance. But this unit is very popular for a reason.
Best Value – Ecosmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts with Patented Self Modulating Technology
The Ecosmart ECO 27 is Ecosmart’s most powerful heater, designed to handle on demand water heating in even the coldest climates. In warm climates it could power most appliances in the household. The ECO 27 self modulates to accurately use energy only when called to do so, which means increased efficiency and increased energy savings. Best of all, it has a lifetime warranty on the unit itself, which is by far the best warranty on the market. It even transfers between owners, if you sell your house. It’ll be easier to sell your house, too, since it raises the market value! And the price is, comparatively, quite reasonable.
The ECO 27 is a heater that can hang tough in the cold of winter, possessing a 3 GPM flow rate at 37-degree inlet water temps, and provide up to 6 GPM with more temperate weather. If you divide that all by its relatively low price, you see a heater that might be a great option for medium-sized households (3-5 people) who don’t want to break the bank.
A couple of reviewers note that the effective flow rate performed significantly below expectations, with colder water than they desired in cold climates. Qualifying for the lifetime warranty has a lot of fine print, and customer service should the unit fail was not responsive enough for other reviewers. And, unless you live in a southern climate, the flow rate might not be high enough to ensure seamless, unlimited, piping hot water throughout a larger household (5+ people).
With a reasonable price tag and the ability to power through colder temperatures, the ECO 27 could be a great mid-sized household option (3-5 people). The effective flow rate in the winter will be lower in cold climates, but you might be able to adjust to a slightly differentiated hot water schedule in the cold parts of the year, with increased performance the rest of the time.
This one is a good choice if you want one that is a step above the Rheem RTE 13 above, without spending a tremendous amount more.
Best Medium Demand Heater –– Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas
This Takagi is an extremely well-reviewed water heater that should be perfect for most households of five or fewer people, even in cold climates. Unlike the ECO 27 above, its 6.6 GPM flow rate should perform similarly in the winter and the summer. Two showers at once shouldn’t be a problem, especially for households with at least one low-flow showerhead. It has a great price for all of its capabilities! There is a digital remote for precise control sold separately, and reviewers say it’s worth it. If you have a house with lots of people who need showers, this is the best choice for you! It’s also a good choice for people who want to hook multiple showers up to the same unit.
This one is similar in usage to the ECO 27, but will be more reliable and allow significantly higher flow rates in the winter/cold climates. The Takagi is extremely well-liked––out of 80 reviews, there is only one 1-star review––and that person warns about installation costs, which are common to all tankless gas water heaters. And, since it is a tankless gas heater, you will save more money over the long term, especially with a reliable model like this.
The price as compared to the ECO 27 is significantly more, and in warmer climates they have similar flow rates, so medium-sized households (3-5 people) in warmer places can get away with the cheaper option. If you are looking for absolute, assured domination over your hot water, a higher demand option might be more up your alley. And as a gas heater, significantly higher upfront costs are required to vent the gas to the outside.
A great mid-sized option if you are sure you want a gas heater, assured of performance in cold and hot weather. But depending on your exact situation, you might be able to get away with the ECO 27 above and have a similar experience for less money.
Best High-Demand Heater – Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater
This is the beast of residential tankless water heaters. Seriously, you can almost see the fur. Someone could take a two showers, run the dishwasher, hand wash a pan, and do a load of laundry––all at the same time! It is a condensing unit, which means it extracts the heat from exhaust gasses for increased energy efficiency––and increased savings for you! It’s also surprisingly compact, given the power it’s capable of putting out. All its beastness comes with a cost that will make it prohibitive for a lot of folks, but if you have a large demand for hot water, this is a great choice.
As a condensing natural gas heater, this Rheem unit will save you the most money in long-term energy costs in the long term, because gas is cheaper and it is extremely energy-efficient (90-98%, under ideal conditions). And with a 9.5 GPM flow rate, you will never, ever run out of hot water, unless you arbitrarily try to push it to the limit for no reason. Cold climates do not threaten to dim your hot water happiness in the slightest, as it comes with freeze protection up to -30 degrees Fahrenheit.
This is by far the most expensive heater on this list, and as a gas heater, it will have significant installation costs beyond just the list price.
Smaller households don’t need something this massive, but for the ultimate hot water peace of mind it’s hard to beat this unit.
To truly maximize your choice of a tankless hot water heater, you need to consider a lot of variables: gas vs. electric, hot water demand, the climate you live in, installation costs, and of course, how much you have to pay. Not every household needs the big behemoth heater, and not every household can get away with the smaller one. There is a lot of technical information worth considering before your purchase.
Gas vs. Electric: This is probably where you should start, as either option has its own advantages and drawbacks. Natural gas/propane is almost always going to be cheaper than electricity, so from a long-term utility perspective, gas heaters will save you more money.
However, the big drawback to gas heaters is upfront cost––not only do the units themselves tend to cost a little more, but because the indoor models require venting, the install cost can also be significantly higher. Your exact household setup will determine the full extent of upfront costs, but the higher price point makes electric heaters the more popular choice. But gas heaters also generally tend to come across as more reliable, based on negative reviews.
Hot Water Demand: Tankless hot water heaters list a maximum flow rate in gallons per minute (GPM), which is the maximum volume they can heat effectively. Showers have the highest flow rates of any appliance––high-flow showers vary from between 2.5-3 GPM, and low-flow showerheads tend to give out around 1.5 GPM.
But it’s not just a matter of counting showers, because you might want to have multiple hot water appliances running at once. The smaller units tend to have a much lower GPM, and could certainly be made to work if you can adjust to doing nothing else hot water-related while someone is in the shower.
Climate: In the United States, northern climates have significantly lower inlet water temperatures, and require higher flow rates to ensure effectiveness during the coldest months. Southern climates can get away with smaller units, because they have to work significantly less hard. Northern climates also benefit the most from the energy savings from tank water heaters, because it’s much more expensive to heat water in cold climates year-round.
Installation Costs: Please be advised that, while gas heaters tend to be more expensive to install, both types have significant installation costs associated with them. The exact amount it will cost to install your unit varies widely depending on your exact situation, but will probably cost at least $300 or more.
If you’re feeling up to it, you can install your water heater on your own but be sure to follow the instructions properly. You can watch this video as a guide but more importantly, follow your own manual.
Many of the negative reviews online reflect complaints about the warranty––we strongly recommend reading the fine print and hiring licensed technicians to make sure you qualify, unless perhaps you are a DIY fanatic.
If nothing else, we hope this list has helped you narrow down the type of water heater you are looking for. All four of these options truly depend on the needs of the individual household; the choice is truly not an aesthetic one, but a technical one. Many people choose the Rheem RTE 13 (option #1) because of low upfront costs, and for smaller households (1-2 people) it is a terrific option. The ECO 27 (option #2) and the Takagi T-KJr2 (option #3) are both good choices for medium-demand households (3-5 people).
The ECO 27 is cheaper, but will not perform as well in colder climates, and the Takagi might be more than some people want to spend. And if you want to be assured of hot water in your heart of hearts, the Rheem RTGH-95 bulldozes the competition, for a price.
See other products, read our reviews for: