- Home Appliances
Best Electric Tankless Water Heaters 2016
A tankless, on-demand water heater can save you a lot of money in the long term compared to a water heater with a tank. It does that in two ways: by eliminating the standby losses of heat that occur while hot water waits in the water tank, but also by giving you a longer average service life (20 years, compared to tank water heaters that last a decade at best).
Electric (as opposed to gas or propane) tankless water heaters have additional advantages: they require no air or exhaust line, and can be installed in small spaces such as a closet or even a cabinet under your kitchen counter. This extra leeway makes electric tankless heaters suitable for point-of-use applications, and it makes them safer because there is no risk of exhaust vent failure.
But where propane or natural gas is available, gas and propane water heaters do have their own advantages: lower energy bills, and copious hot water even in cold climates.
In this article, you will find reviews of the top brands of electric tankless water heaters on the market, with their strengths and weaknesses. Having read it through, you should have a better idea of your options, and be able to decide which electric tankless water heater best suits your needs.
Choosing the Best Tankless Water Heater
Tankless or not, the purchase of a water heater is one of those occasions in life when you do not want to be excessively frugal. If you buy a cheap water heater and it lets you down, you are likely to find you cannot shower or wash the dishes. You may be forced to pay lots of money for spare parts and contractor services and end up wasting a fortune on a low-quality junk product. It is wiser to pay more for a high-end water heater now than to get stuck with an inferior water heater for the next few decades.
Many times, people choose a tankless electric heater without paying attention to the product specs and their own hot water needs, and end up complaining that it doesn't heat the water. Note that here are really small tankless water heaters called "single point of use." They are for supplying hot water to a single faucet, and if you get one of them and link it with your entire house, you will get lukewarm water. Then, there are mid-range water heaters, which do well if you are in a warm-water region such as Miami. If you take one of these mid-range units to Maine and connect it to a huge jacuzzi, you will get lukewarm water. If you do not consider the water heating capability your home demands, and you just try to spend less by getting the smaller unit, you might find out later that you should have gotten the bigger water heater. Below, I discuss water heating capability in greater detail.
Another complaint we come across in products from all brands is flickering lights. An electric tankless unit will pull a lot of amps from your system, and if you have a home with old electric infrastructure, or if not enough juice is being supplied to your home, you might see your lights getting dim. That happens rarely, and only with units above 20 kW. LED lights are generally more prone to flickering. Some people blame the water heater manufacturers because their lights go dim. But the problem is their home not having enough electric power, and it is not fair to blame the water heater for doing its job, that is taking the electricity and converting it into heat.
Moving on, let us have a look at some of the key features you should take into consideration when choosing the best electric tankless water heater.
Temperature: For washing hands, 100 °F is fine. For showering and manual dish washing, you may want the water somewhat hotter than that, but not much. Temperatures higher than 120 °F risk scalding people, and the US Consumer Product Safety Commission actually urges users to set water heaters below that level. Between 110 °F and 120 °F is a reasonable target temperature for residential hot water. When choosing your on-demand water heater, make sure it can attain that temperature given your expected rate of use and the base tap water temperature in your area. To calculate the answer, you need to consider the water flow capacity and the power of the heater.
Water flow capacity: Measured in gallons per minute (gpm), this tells how much water can pass through the heater at a given time. Ordinary kitchen and bathroom faucets and shower heads have a maximum flow capacity of 2 gpm each. A heater's specified flow rate is often mistaken as a measure of how much hot water the heater can supply, which it is not. A 4-gpm tankless water heater will allow you to run two hot-water faucets at full speed, but the water you get will not necessarily be as hot as you wish. If the heater does not have enough heating power, the water will pass through without fully heating up, and you will get 4 gpm of lukewarm water. To avoid disappointment, you should remember that the true gauge for an electric water heater's performance is kilowatts, not gpm.
Power: Power in kilowatts (kW) tells us how much electric energy is converted to heat every second. With some basic physics knowledge, we can calculate that 1 kW is enough to heat water flowing at 1 gpm by about 7 °F. We know that an average faucet delivers 2 gpm, so to raise the temperature of water coming out of a kitchen faucet by 50 °F, we need about 14 kW. If you are in Florida where the base temperature for tap water is 70 °F, you will get pretty scalding hot water at 120 °F running at full speed from your faucet. Indeed, that level of power, in Florida, would be quite enough to run a kitchen faucet and an ordinary shower head at the same time.
But more kilowatts would be needed to get the same amount of hot water in North Dakota. Taking a look at our map, we find that base water temperature there is about 35 °F less than in Florida, which requires an extra 5 kW for every gpm of water. For 2 gpm, we would need an extra 10 kW. So a 24kW tankless heater in Grand Forks will do what a 14 kW tankless heater does in Jacksonville.
Based on these examples and the map, you should be able to calculate how many kilowatts you need. Add 1 kW for every 7 °F you want. Multiply that with the gpm you need. It is best to get something a little more powerful than what this calculation gives you, just in case. If you are living in the northern US and you want to use a tankless water heater for your entire house, I advise you to get the biggest possible unit.
Efficiency: There is no "most efficient" electric water heater. Electric water heaters simply convert all the electric energy into heat energy, so all of them are more than 99 percent efficient. With electric water heating, you can only waste energy if the faucet is too far away from the heater or if the heater is slow in reacting to changes in water flow rate and adjustments to the water temperature.
Minimum flow rate for activation: Tankless water heaters don't start heating until their sensors tell them a certain amount of water is flowing through. If the water flow is below the threshold, there will be no heating and the water will remain cold. If the minimum flow rate is something close to 1 gpm, there's a good chance you will accidentally fall below the threshold and get an interval of cold water. Many people who use a tankless heater for the first time become really frustrated by the occasional fluctuation. In fact, it is very simple to avoid this problem. You should check out spec sheets for different tankless units, and make sure you get one that activates at very low flow rates. As far as I know, EcoSmart tankless water heaters are the winner in this category with an activation threshold of 0.25 gpm. EcoSmart products are reviewed in greater detail below.
Thermostat and flow rate modulation: A decent water heater should give you some control over the outgoing water temperature. Some cheap units feature a control valve with high and low settings, but usually this is a power setting rather than a temperature setting.This will not give you the best showering experience and there may be times when the water gets way too cold or way too hot. Without a proper maximum temperature setting, the unit can even malfunction and burn itself out. On the other hand, high-quality electric tankless water heaters come with the option to set a desired water temperature and are equipped with various sensors to make sure things function as you wish.
Build quality and warranty: You need a decent warranty to feel confident about your water heater, but if the heater breaks down there will be a lot of inconvenience, even if the manufacturer is perfectly helpful and willing to stand behind the product. So it's crucial to buy a better-built water heater with a low probability of malfunctioning. Build quality is an elusive feature that you cannot find out by looking at product specs. In fact, the only practical way to see if a product is well-built is by resorting to the experience of people who have actually used the device. I have read through hundreds of customer reviews to detect quality issues for top brands, and I present my findings below.
Now that the key topics have been covered, we can proceed to the reviews.
Eemax On-Demand Electric Water Heaters
The product pictures make one think this company is selling some sort of connector device for the cable TV, but in fact these are tankless water heaters. Because Eemax is a popular brand, it deserves a place in this list. Nevertheless, the features and quality of Eemax water heaters are hardly the best, though they are okay.
First, let's have a look at the minimum flow rates. I've seen one Eemax that is activated at 0.3 gpm, and gives a temperature rise of 33 °F at 0.5 gpm. You would need half a dozen of those to heat water for one kitchen faucet. There are some models with 0.5 gpm minimum flow, but they are also hardly powerful enough even for point-of-use installation. All Eemax tankless water heaters that have enough kilowatts to be of any use need at least 0.7 gpm to start heating, and some of the bigger whole-house units need 0.9 gpm. In short, the water-flow sensitivity of Eemax products is mediocre at best, and definitely doesn't compare with the 0.25 gpm found in all Ecomart tankless water heaters, which I review below.
Some Eemax water heaters have no thermostat or temperature-setting option. Luckily, most of the larger models that are worth purchasing and installing have thermostats and allow you to set a desired temperature that the heater will stick to as long as its capacity is not exceeded.
Price-wise, Eemax does not seem to be an auspicious choice. Eemax water heaters are more expensive than Stiebel Eltron products with equal heating capacity, and Stiebel Eltron is by default the most reliable supplier in the market.
Eemax claims to be top quality, boasting its products are made in the USA, but customer reviews tell a different tale. They indicate something is terribly wrong with the build quality of Eemax tankless water heaters. There seems to be a recurrent issue about the heating units and motherboards getting fried. Some patient users replaced parts many times over the years, while others invoked the warranty to get whole new water heaters, only to find out that they did not work either. The company stresses that all air in the system should be removed during installation to avoid the malfunctioning of the water heater, and some suggest that air trapped in pipes could be the reason for so many incidents of heating unit failure. However, that does not explain why tankless water heaters of other brands do not suffer such a high rate of self-incineration.
If you decide to buy from Eemax, get one with enough kilowatts to heat enough water for you, and make sure you get one with a thermostat. Models from the Eemax Home Advantage line, for example the Eemax SS038240T2T2, have relatively high wattage and a nice-looking digital thermostat.
Rheem RTE 13 Electric Tankless Water Heater
Rheem is known to be a reliable manufacturer of water heaters and its tankless gas water heaters are indeed some of the best on the market. However, Rheem electric water heaters are not the best on the market. This does not mean Rheem RTE series are a bad choice; when the price advantage is factored in, they could even be called decent. In fact, the Rheem RTE 13, with 13 kW of power and a 4 gpm flow rate, is the best-selling on-demand water heater.
Of the various sizes of Rheem electric tankless water heaters, the RTE 13 and RTE 9 are the two popular models that could be given a try; other models get too many negative reviews from customers. RTE 13 has enough power to provide very hot water for one faucet in the northern US, and could even keep up with the needs of a small flat in the South. RTE 9 has 9 kW of power, as the model number suggests; this model should only be preferred for point-of-use.
All models from Rheem have an activation threshold of 0.4 gpm. That's good, but not as good as Ecosmart, which costs only slightly more.
If you need a quick and cheap hot water fix for the kitchen faucet ,and you do not care a lot about features or long-term reliability, you might want to try the Rheem RTE 13 or RTE 9 models, but you should consider their disadvantages before deciding.
First, Rheem electric units do not have a proper temperature control, let alone a heat modulation system. There is a manual setting valve on the box with low, high and medium, but it is a power setting, not a temperature setting. It appears that after setting the power, the only way to control the temperature is to turn the hot-water faucet itself up or down, and you should be prepared for a lot of fluctuations.
Next, although many end up happy with Rheem, customer reviews also indicate that negative user experience is not rare. Among complaints about faulty products and unreliable customer service, there are reports about Rheem water heaters failing to stop heating after all faucets are closed. This causes a build-up of extremely hot and steamy water, sometimes deforming the water pipes and burning the heating elements and the motherboard.
A look inside the casing shows that the heating system looks rather simple, with fewer wires going around than in products from higher-end brands. Users who took a deeper look, including some who claim to be contractors themselves, verify that the flow-rate and temperature sensors in Rheem water heaters look barely adequate. The single wire that serves as the thermostat is glued to the heating unit in an obviously shoddy way, and it just snaps then and again, letting the unit overheat. That explains the complaints of the unit malfunctioning, and it explains the price, too. Rheem RTE water heaters are built to be cheap.
In conclusion, Rheem on-demand water heaters are far from being the best, although they do offer a viable and cheap water heating solution. This is not exactly the water heater I would recommend to a friend, but if you are serious about going cheap, this is the one that has the best chance to perform well at the lower price range.
Ecosmart ECO Electric Tankless Water Heaters
In sales, Ecosmart tankless water heaters are second only to Rheem, and this is no surprise. Among the major manufacturers, Ecosmart water heaters offer an optimized balance of price and performance. Costing only slightly more than Rheem products of similar size and power, Ecosmart units do not suffer the quality issues found in their cheaper competitors. They get much better ratings from customers and are equipped with the key features needed for proper hot water use.
One thing that can make a tankless water heater suck is too high a minimum flow rate for activation. Using one faucet at a time, and mixing cold with hot water, you are very likely to fall below 0.5 gpm of hot water use, which is low enough to trigger most tankless units to stop, giving you a cold water shock, and wasting time and water until you readjust the temperature. Larger, whole-house units can have a threshold of 0.75 gpm or more, and that makes things even more difficult. Well, all Ecosmart tankless water heaters, even the largest 27 kW ones, have a minimum flow rate of 0.25 gpm. This is by far the best activation threshold in the market, and I don't think EcoSmart is promoting this feature enough.
Next, Ecosmart tankless water heaters have a clear temperature control panel with a digital display that allows you to set outlet water temperature in one-degree intervals. Once set, the water heater will auto-adjust the power to attain the desired temperature even with varying flow rates, eliminating sharp fluctuations in warmth, and saving time, water and energy. Ecosmart products have a state-of-the-art modulation system with inlet and outlet temperature sensors, as well as thermostats connected to the heating elements and a flow-rate sensor. That gives Ecosmart flexibility in providing you with hot water and adequate protection against overheating.
Sifting through the customer reviews on the various EcoSmart models, I have not found any recurring or alarming complaints (though a few people buy a low-power EcoSmart and complain it does not heat enough). In general, people end up very happy with these water heaters, and there are next to no cases of the units dying in some way. I can confidently call EcoSmart tankless water heaters well-built and long-lasting.
There is a lifetime warranty on Ecosmart water heaters, and that sounds great. Unfortunately, the device must be installed within 30 days from the date of the receipt by a licensed electrician and a licensed plumber; if you are a DIY person, your warranty is void. I've got mixed feelings about the reliability of this warranty, but that does not change the fact that Ecosmart units have great quality with great price.
The high-kilowatt models such as ECO 24, ECO 27 and ECO 36 get almost perfect ratings from customers. Any one of these should be able to supply two faucets with reasonably hot water flow near the Canadian border and in January. Smaller units make a great choice for warmer locations and point-of-use applications. Make your calculations as explained above, and factor in the distance to the faucets to avoid underbuying.
All in all, Ecosmart is the brand I would go to, if I needed an electric tankless water heater right now. All the key features you want to see in a water heater are present in EcoSmart units. The products boast proper workmanship with very few cases of failure. What really makes Ecosmart stand out is the very low activation flow rate, a key quality that many people seem not to pay enough attention. Finally, with the price being right, I cannot do anything but recommend Ecosmart tankless water heaters as a great purchase.
Stiebel Eltron Tempra® Plus
Someone called Stiebel Eltron "the Mercedes-Benz of on demand water heaters". That is a fitting analogy in many ways. Just like the car, it is made in Germany, the nation known for its major appliances industry. More importantly, its features and build quality represent the ultimate best available in the market. If you don't like Mercedes, you were not meant to drive a car. If you don't like Stiebel Eltron, you were not meant to shower with an electric tankless water heater.
Being one of the pioneers of the industry, Stiebel Eltron produces tankless water heaters with all the features needed for complete control over the water temperature. There is a plethora of sensors that check the flow rate and temperature, eliminating any possibility of the unit overheating or giving you a cold shower. Thermostats and precise temperature settings are found in every model, and some models even have the ability to auto-adjust the flow rate so as to completely prevent fluctuations in temperature. These water heaters get almost perfect feedback from users, and in fact, I have not been able find any legitimate complaints raised by customers of Stiebel Eltron.
Stiebel Eltron water heaters come with a warranty of three years for parts and seven years for leakage. This is one of the best warranties you can get for a tankless unit. The warranty document is short and simple without fuzzy conditions that could void the warranty. In any case, not many people find themselves in a situation where they have to resort to the warranty, because Stiebel Eltron products just don't let people down. This is the most reliable and established water heater brand and you can rest assured that you will be getting top quality and top service.
These water heaters have a very sleek and high-end look.
There are two series by Stiebel Eltron: Tempra and Tempra Plus. They look very similar, but the Tempra Plus series is slightly more expensive and has some more features. There is a digital display that shows the set temperature, which is a minor upgrade. More importantly, Tempra Plus units are equipped with what is called Advanced Flow Control. That means Tempra Plus can adjust the amount of water flowing through the heating elements so as to prevent any ups and downs in water temperature, no matter how many faucets you open. There is absolutely no way the output water temperature can vary from the set value if you have a Tempra Plus tankless water heater. Obviously, people find this advanced feature useful, because many prefer the Tempra Plus to than the plain Tempra.
The activation threshold for Tempra and Tempra Plus water heaters ranges from 0.37 gpm for the smaller 12 kW unit to 0.87 gpm for the largest 36 kW unit. This is not as good as EcoSmart, but the Advanced Flow Control feature should more than make up for any awkwardness.
I need to mention that the most powerful electric tankless water heater I have ever come across is the Tempra 36 Plus. It has a 36 kW heating capacity and can give you enough very hot water for three faucets used simultaneously, even in a cold-water region. If you want something for the whole house, and you are in the North, the Tempra 36 Plus may be what you are looking for.
In conclusion, should you decide to purchase a Tempra Plus tankless electric water heater, you will get nothing less than premium quality. Stiebel Eltron's only competitor is the EcoSmart we discussed above. Indeed, my personal choice would be EcoSmart because of the lower activation threshold and the great price-to-performance ratio. Yet, I have to admit that the best electric tankless water heater in the market is produced by Stiebel Eltron, and there is no way you will regret installing one of these in your home.
Best Heat Pump Water Heaters: A heat pump water heater transfers ambient heat to water, similar to the way a refrigerator works. Their edge is their unrivaled efficiency in energy consumption, which makes them the choice of people who prioritize energy conservation above all.