Best Tankless Water Heaters Reviews 2022 – Buyer’s Guide and Reviews

You may have come across tanks located on the sides of houses as you drive around your neighborhood.  Well, chances are, those tanks are holding hot water ready to be used.  It’s an old school way of hot water heating – in comes the modern tankless water heater!

Tankless water heaters, also known as ‘on-demand’ or ‘instant’ water heaters, don’t require a tank and provide hot water only when needed.

They provide numerous benefits including an endless supply of hot water, a smaller physical footprint, and higher energy efficiency which will save you money on your energy bills!

So, it’s a no brainer that tankless water heaters have clear advantages over traditional tank water heaters.

But how do you go about deciding which one is right for you?

In comes YourBestPicks to the rescue!  We’ve reviewed dozens of models to bring you the very best 10 tankless water heaters for 2022.

Best Tankless Water Heaters Reviews 2022

It’s a tough job to decide which tankless water heaters are the best.  Amongst many factors, three key specifications have been considered:

• Flow rate:  Measured in gallons per minute (GPM), the flow rate is the amount of water that a tankless water heater can deliver.  The value will range from an activation flow rate (minimum flow required to activate the heating function) to a maximum flow rate.
• Temperature rise:  The temperature rise is the difference between the incoming and outgoing water temperature.  For example, if you set the temperature to 105 °F and the incoming temperature is 50 °F, a temperature rise of 55 °F is required.  Hence, a greater temperature rise will mean a lower flow rate as more time will be required to heat the water as it flows through the unit.
• Features:  Different tankless water heaters come with various sets of features, from flow control and safety locks to unique heating methods and installations.  We consider all these variables in determining a final ranking.

Apart from these factors, we also take into account the quality of the unit, how well it’s been reviewed by customers and the reputation of the brand.

The last thing you want is to purchase a tankless water heater, install it (which can be quite expensive) and then realize it’s not really a good fit for your home.  Lists like this come in handy to help you with your decision.  So, without further ado let’s begin!

1.  Stiebel Eltron Tempra 24 Plus – Best electric tankless water heater  

Stiebel Eltron is a German company that was founded in 1924 by Dr.  Theodor Steibel.  They are considered one of the world’s leading specialists in manufacturing water source heat pumps.

Not to sound clichéd, but putting your trust in German engineering is usually a smart investment.  It comes as no surprise that one of their electric tankless water heaters makes this list in the form of the Tempra 24 Plus.

It has been designed with two whole sets of flow rates – one for 240 volts and the other for 208 volts.  You’ll get a higher flow rate using the more power consuming option, but you’ll have to make sure there is enough juice to get it running.  It’s a smart design decision as it caters for a variation in electrical set-ups and will end up saving you some extra cash if you decide to configure it for the lower voltage option.

As it stands, the flow rate ranges from 0.58 GPM – 5 GPM.  Of course, this range will depend on the temperature rise required.  For the most part, getting close to 5 GPM will provide you with enough flow for 2 bathrooms and other common utilities of a medium sized home.

Need something more powerful?  Just like other brands, Steibel Eltron also offer a range of units in their Tempra Plus line, like the Tempra 29 or 36 which offer greater flow rates.

Stiebel Eltron have jumped on the trend of producing eco-friendly products, with the Tempra 24 Plus being electrically powered and 99% efficient.  Almost all of the energy being used is going towards warming the water that makes your shower so enjoyable.  It’s good news for the environment and your wallet.

The size of this tankless model is slightly larger than other electric builds, but it’s still relatively sleek.  It features an analog dial with a digital temperature output that ranges from 86 °F – 140 °F.  Rather than offering exact incremental degrees, Steibel have opted for a more user-friendly display that points out the recommended settings for whatever type of usage you require (hand washing, residential or commercial).  It’s simple and straightforward and makes using this device a headache free process.

All signs point to the Stiebel Eltron Tempra 24 Plus being the best electric tankless water heater you can get your hands on.  Over 90 years of experience has gone into this product, so you can rest assured that you won’t find a better tankless water heating solution anywhere else.

2.  EcoSmart ECO 27 Electric Tankless Water Heater – Best budget tankless water heater

Smart, efficient and small.  These three words perfectly describe EcoSmart’s ECO 27 Electric tankless water heater.

We’ll explain.  You see, most tankless water heaters come with some form of modulation which keeps energy loss to a minimum by changing the power supply depending on the current demand.

So how does it work?  As the water flows through, it’s heated by 3 heating elements that work one after the other, based on demand.  Therefore; certain situations will only require the use of 1 heating element, whilst other’s will demand that all 3 be in action.  This level of control helps save as much energy as possible – good news for the planet and your wallet!

The temperature is displayed via a modern and sleek digital interface and can be set from 80 °F – 140 °F,  which is more than enough for any residential needs.  Surprisingly, you can set the temperature at 1 degree increments – a very cool, but somewhat unpractical feature.

Refreshingly, EcoSmart have disclosed all the information regarding the capabilities of their unit.  The coldest inlet water is about 37 °F, which you may experience if you live in the northern part of the United States during winter.  The company have advised a 2.7 GPM flow rate is what you can expect to heat this water to a warm 105 °F.  Conversely, if you were to live in a much hotter climate, such as Florida, you can expect a flow rate as high as 6.6 GPM.

To put things in perspective, a standard shower head is 2 GPM whilst a dishwasher is 1 – 2 GPM.  So unless you live in a very cold area, you shouldn’t have an issue with getting enough hot water for a small to medium house.  Note that the minimum flow rate to start the heating process is 0.25 GPM, meaning a dripping faucet probably won’t activate the unit.

EcoSmart have 6 tankless heaters in their ECO line-up.  If you live in a particular cold area, it may be wise to consider purchasing the more powerful ECO 36 as it offers a higher flow rate.  Similarly, if your household has a lower water consumption and the inlet temperatures are generally higher, going with ECO 8, 11 or even 18 may be the better choice for you.

Overall, the ECO 27 is an excellent choice for someone wanting to save money and reduce their environmental footprint.  A win, win if you ask us.  Add in a lifetime warranty and it’s hard to look past this model as the number 1 budget friendly option.  Indeed, EcoSmart have lived up to their name by providing an eco-friendly product that conveniently only uses the resources you need.  In this modern world, it’s a great incentive and deserves our recommendation.

3.  Takagi T-KJr2-IN-NG Indoor Tankless Water Heater – Best natural gas tankless water heater

The Takagi T-KJr2-IN-NG represents the first tankless water heater run by natural gas on this list.

Natural gas heaters work by heating the water with a gas burner (instead of an copper/metal element).  Therefore they have some innate advantages over their electrical brothers like costing less to operate, being able to heat the water at a faster rate, and working during a power outage.

That heat loss is in the form of exhaust (think of the exhaust release you get from a pilot light on a stove) and so extra costs in installing and purchasing venting equipment will be required to get this unit operational.  The good news is you get options of a vertical (through a roof) or horizontal (through a wall) ventilation set-up.

Consistent water temperature is maintained through thermistors and an air-fuel-ratio (AFR) sensor that monitors efficiency and reduces emissions.  The result is an energy factor of 0.81 – 0.83 which is defined by the amount of hot water produced per unit of fuel consumed over an average day (the higher the better).  It turns out, this is a pretty good number compared to the average tank gas heaters which are around 0.6 – 0.7.  Still, it’s significantly less than electric tankless heaters which can top out at around 0.97-0.99!

On top of the AFR sensor, the Takagi also comes with a water and exhaust temperature safety control, and an internal freeze protection system.  It makes for a feature heavy unit that means you can leave it on auto-pilot for most of the year.

Temperatures range from 99 °F to a scalding (and commercial grade) 167 °F, so you’ll have no issues getting to your desired heat level!  These settings are controlled by a convenient remote, leaving the Takgi to have a sleek and minimalist design.

Speaking of sleek, this is actually the smallest tankless water heater in the Takagi line-up, measuring at 20.3″ * 13.8″ * 6.7″ and weighing 38 pounds.  It is still bigger than other electrical models, but significantly small enough to place just about anywhere that is practically possible.

The T-KJr2-IN-NG is one of the highest rated indoor tankless gas heaters and for good reason.  It has an excellent temperature range and fantastic flow rate.  You also get a 10 warranty on the heat exchanger and 5 year warranty on parts, which speaks volumes about the quality product that this water heater is.  With a decent efficiency level, the model will eventually pay for itself down the road, making the Takagi a smart and powerful solution to your hot water heating needs.

4.  Rinnai RL75iN Natural Gas Tankless Water Heater – Strong performance with scale detection system

If you’re looking for a tankless water heater solution that is suitable for both residential and commercial applications, than the Rinnai RL75iN may be the perfect option.

First things first, this beast can reach a maximum flow rate of 7.5 GPM – easily enough for 2 to 3 bathrooms.  Residential temperature ranges from 98 °F – 140 °F, with commercial settings reaching a super-hot 160 °F, though an additional controller must be purchased for this configuration.  The temperatures are set via a push button mechanism on the front panel, and are displayed on an LCD screen.

Ok, now that we have the most critical (and impressive) stats out in the open, it’s time to get down to the installation.  This tankless water heater is of the indoor variety and measures at 24″ * 14″ * 9.3″, making it decently sized for a gas powered model.  Still you shouldn’t have much of an issue finding a suitable area for where to plonk this machine.

Rinnai have provided horizontal or vertical ventilation options so can play around with the set-up that works best for you.

Considering a price tag of over $1000, one might expect some extra components for the ventilation, but alas, you won’t get any in the package.  A quick search on Amazon will show up the right kit you will need to get this unit operating correctly.

Apart from two installation options, you also get two options for fuel source – natural gas or propane.  The later is generally more expensive, but also more efficient (has double the BTU rating), meaning you may actually save more money in the long term.  This is of course dependent on your own needs of the system, so it would be wise to check with a technician first.

The RL75iN features a number of monitoring sensors that ensure the unit works safely inside your home, with two in particular that stand out:

There is a cool temperature lock system that prevents accidental changes to the water temperature.  It’s a perfectly suitable compliment to an indoor heater that is susceptible to being touched by unwanted hands – especially if you have children running about!

Secondly, there is a unique inbuilt scale detection system which indicates when there is a build-up of scale.  This is the white and papery stuff you see in pipes and can drastically reduce the lifespan of your water heater.  It’s a great preemptive tool to alert you when maintenance is required and will help keep your tankless water heater ticking for a long time to come.

This unit comes with an energy factor of .82 for both natural gas and propane, making it highly energy efficient and granting it the famed Energy Star certificate.  It’s a good thing for your wallet as you’ll be making energy savings.  Oh, and chances are you’ll be using this for a long time as the Rinnai warranty spans 5 years for parts and 12 years for the heat exchanger.

At the end of the day, you get what you pay for with this premium tankless water heater.  With its myriad of features, positive reviews and powerful temperature and flow performance, you can pretty much install it and then set it on autopilot.  It’s a definite winner in our books and deserves a top-half ranking.

Pros

• Up to 7.5 GPM flow rate – enough for 3 bathrooms
• High end commercial temperature setting of 160 °F
• Scale detection system making maintenance much easier
• Temperature lock safety feature
• Long warranty period
• Durable and well-made design
• High energy factor of .82 for natural gas and propane
  

Cons

• Does not come with a ventilation kit
• Pricey

Tip:  Most tankless water heaters require regular maintenance in the form of flushing with a cleaning agent.  This is typically performed a couple of times a year.  Every model is different, so it’s a good idea to read the manufactures recommendations.

5.  Titan SCR2 N-120 Electric Tankless Water Heater– Best point of use tankless water heater

The Titan SCR2 N-120 is an indoor model that performs to a solid level across the board.

It’s advertised for point of use applications and rightly so.  Measuring at  10″ * 7″ * 3″ and weighing only 8 lbs, it is the smallest unit on this list.

Heck, it’s so small that it makes the portable Eccotemp model (mentioned at number 6) look big and chunky.  In summary; you’ll have no issues fitting this tankless water heater near any utility that requires hot water.

The tiny size doesn’t limit the capabilities though, as this unit can produce a maximum flow rate of 4.0 GPM at a 20 °F temperature rise.

Sounds good right?  But here’s the kicker;  Titan have specified that you should only be using this model with an inlet water temperature no lower than  65 °F.  Any lower; and it won’t be able to keep up with the required temperature rise.

The temperature can be set via a push button mechanism and is displayed by a simple low to high graph.  It’s a no frills approach but it gets the job done nonetheless.

The SCR2 N-120 maintains a constant temperature by using a sampling system that monitors input and output water temperatures 21 times per second, and then making the necessary adjustments to the flow rate.  It effectively prevents cold water from unexpectedly ruining your hot shower; but it’ll also mean a reduced flow rate will be enforced.

The N-120 is actually the most powerful model in the SCR2 line-up which means it also draws the most power.  Keep in mind that with an energy rating of 99.5%, you will definitely end up saving money over time versus tanked solutions.

Overall, this model ticks all the boxes but doesn’t actually excel in anything in particular.  It’s not a bad thing, and considering the decent pricing it’s actually pretty good value for what you get.  Titan have produced an all-round solid tankless water heater that is perfect for supplementing an existing water heating system.

Pros

• Very small build
• Impressive maximum flow rate considering the size
• 10 year warranty on all water carrying components
• Sampling system to maintain constant water temperature
• Competitive pricing
  

Cons

• Recommended to use only with relatively high inlet water temperature
• High starting temperature of 105  °F

6.  Eccotemp L5 Portable Tankless Water Heater – Best portable tankless water heater

When it comes to portable tankless water heaters, the Eccotemp L5 is our recommended model.

In fact, most people would agree with us when we say that this is the best portable tankless water heater you can get for the money.

This unit is powered by liquid propane which is extremely efficient and perfect for users on the go.  It’s not just for camping though as you may wish to use this for point of use applications, or even to provide hot water needs to a cabin or an outdoor shower by the pool.

The flow rate can get up to 1.4 GPM with a temperature range of 80 °F to 150 °F.  Essentially, you only want to use this unit for one utility at a time.

For a price that hovers around $100, we were very impressed to find that you get everything you need to get this unit working – a shower nozzle (for portable showers), hose adapter (to connect to a water supply), hardware kit, gas regulator and vent shields all come with the price tag.  The only thing you need is a propane tank!  However; if you do need to use it off-grid, ensure you have two D-cell batteries to power the ignition.

On the front panel are two dials that allow you to control the gas and water flow so you can tweak these until you get the perfect balance between pressure and temperature.

Portability, small dimensions and weight go hand in hand.  Thankfully, the L5 measures at 16.5″ * 11.5″ * 5.5″ with a weight of 13.8 lbs making it very convenient to take it wherever you may go.  It also has a handle and hooks making is super easy to carry and hang on whatever can support the weight (which is pretty much anything).

Considering the price, there isn’t a lot to dislike about the Eccotemp L5.  The one thing that is a recurring issue is the ignition flame being blown out by the wind.  There are vents throughout the design with open holes for the wind to channel through, causing potential blow outs.  Covering the unit with a tarp or other non-flammable material will solve this minor headache.

All things considered, this is a great entry from Eccotemp and provides enough power and temperature to provide hot water for single application needs.  It’s an extremely well received model with an overwhelming positive response from users.  This is the number 1 go to tankless water heater if portability is your primary concern.

Pros

• Small and lightweight making it very portable
• Provides enough flow rate for single use applications
• Very affordable
• All accessories provided – you only need a propane fuel source
• Ability to run on 2 D-cell batteries when ‘off-grid’ (batteries not included)
  

Cons

• Venting design means that wind may occasionally blow out the ignition flame
• Relatively short 1 year warranty

7.  Noritz NRC98-DV-NG Direct 9.8 GPM Indoor Condensing Vent – Extremely energy efficient and powerful with condensing function

Noritz is a big player in the tankless water heating world and are reported to have one of the largest manufacturing plants.

The Japanese company has been around since 1951, with the American division being established in 2001.  Indeed, Noritz are looking to further solidify their foothold in a global market that is demanding powerful and eco-friendly warm water heating solutions.

So does the NRC98-DV-NG stand up to the challenge?

Yes!  If you are looking for a model that is both powerful and extremely efficient, then this is perhaps the right tankless water heater for you.  You see, it comes with an amazingly high 9.8 GPM flow rate meaning it’s perfect for households with multiple bathrooms.  It doesn’t skip out on efficiency either, thanks to the design, we’ll explain.

Inside sits two heat exchangers.  The first pre-heats the water so the second – and primary exchanger- doesn’t have to do all the work.

Such a design may not seem that efficient, but it actually is, all thanks to the condensing function.  The flue gas (or exhaust) from the first heat exchanger is actually used as the heating source for the second and therefore drastically increases efficiency.

The result is an energy factor of 0.91 for natural gas and 0.92 for liquid propane – an impressive feat that is significantly higher than other gas powered models which usually range in the high .70s to low .80s.  It also leaves the leftover exhaust fumes at much lower 100 °F, resulting in less expensive ventilation, which can either be set up horizontally or vertically.

The entire process calls for a more sturdy build, with the copper heating elements being 25% thicker on average than in other tankless water heaters.

This engineering makes the NRC98-DV-NG the largest unit we’ve recommended.  Weighing in at a hefty 58 lbs and measuring 24.2″ * 18.3″ * 9.4″, this indoor models begs to be set up properly the first time so you won’t have to hassle with any relocation.

The unit comes with a temperature dial that has 3 settings.  Alternatively, you may opt for a separately purchasable remote which has 9 temperature settings that goes up in increments of 5 °F.

Temperature ranges from 100 °F to 140 °F.  The starting value is quite high and it would have been nice to have a bit of flexibility on the low end.  In any case, this unit is more than capable for reaching the temperature rise required to get to the minimum threshold, even with a very cold water inlet.

Noritz provides all the safety features you would expect at a price bracket of over $1000.  Freeze protection up to – 30 °F, condensate overfill, a flame sensor and overheat prevention are just several things that will keep this model ticking safely within your home.

All things considered, Noritz have provided a very capable, extremely efficient and eco-friendly tankless water heater.  Not only does it keep up with the demands of the modern, environmentally conscious consumer, but it also does not make concessions in providing a powerful water heating solution.

Pros

• High efficiency, and low exhaust output thanks to condensing function
• Inexpensive venting materials required
• High 9.8 GPM flow rate
• Slew of safety features to run smoothly indoors
• Long warranty of 12 years on heat exchanger and 5 years on parts
• Well built and durable design
  

Cons

• Minimum temperature is quite high at 100 °F
• Big and bulky
• High-end model comes with a high-end price

8.  Rheem RTE 13 Electric Tankless Water Heater – Small and compact

Founded in 1930, Rheem has become one of the largest manufacturers in the water heating industry in the United States.  They offer both tank and tankless water heater products and so it should be no surprise to you (or us) that they should at least be considered to make an appearance on this list.

To actually make this list, it needs to be one of the best tankless water heaters, and the popular Rheem RTE 13 fits the bill. 

First things first, it’s actually one of the most compact models at only 10″ * 7.25″ * 5″ and weighing in at 8 lbs, making it perfect for a living situation where space is at a premium and for hooking it up close to the utility requiring the hot water.

Something has got to give due to the tiny physical footprint and in this case, it’s the maximum flow rate of 4 GPM.  It’s not terrible by any means, but you need to keep in mind that in an ideal situation, you’ll get enough hot water for a standard shower head and kitchen sink.

Even the most powerful model in the Rheem line – the Rheem 27, only offers a flow rate of 5 GPM.  If you’re in need of something more powerful, you’re best to look at another brand.

To seriously consider this product you should be using it in two ways:

• As a point of use application which means installing it for one utility only, rather than to your whole water system.
• If you have a small home, like an apartment where only 1 or 2 people are using the facilities you can get away installing it directly to your water inlet pipe so it can supply warm water to your entire household.  As always, figuring out your exact GPM requirements will determine if this unit provides enough flow.

Having said all that, we must give props for Rheem as they have advertised this as a point of use application, so it is clear they know the limitation of their own product.  This isn’t a magic bullet for all your warm heating needs, instead, it’ll be a perfect solution dependent on your living situation.

Still, many people have fallen in the trap of getting this product only to be disappointed by the low flow rate.  You’ve been warned!

In terms of design, it follows a utilitarian approach with an analog dial that allows you to set temperatures from a scale of low to high (125 °F).  It also has a standby mode and system active light.  The standby mode indicates when the system is off, meaning no hot water is currently being generated.  This will save you energy bills as you won’t be using any power when you’re not using hot water.

Many customers have reported quality issues with this product failing in less than a year in a number of cases.  Some of these issues can be chalked up to an incorrect installation or failure to perform regular maintenance.  However; these reports are more common than in other water heaters, so there’s definitely some truth to them.

The biggest sell point for this unit is the price which is well below $400, making it one of the most affordable units in its range.  However; you’ll find this figure blowing up if you decide to get several of these machines for different utilities.

If you stick with one unit, you’ll be saving money on energy costs, with some users reporting savings of $35 a month.  With such a cost reduction, you’ll end up paying for the unit and a professional installation (required for the warranty) in 1 to 2 years.  Combine this with a 1 year parts warranty, and 10 years on the heat exchanger and it would be wise to consider this budget solution if you have low to moderate hot water needs.

9.  SioGreen IR14K220 Point Of Use Infrared Electric Hot Tankless Water Heater – Maintenance free water heating solution

SioGreen is a relatively new player in the tankless water heater market having been founded in 2008.  They’ve made a name for themselves in this short time by being the only manufacturer that produces hot water with an infrared quartz heating element.

In contrast, most water heaters use a metallic coil as the heating element which can corrode overtime and is subject to calcium and limescale build up.  The long term effects of this is a less efficient or broken water heater which will end up costing you more to run.  It’s for this reason that most manufacturers recommend quarterly or annual flushing to clear out the system of impurities.

The patented process has been reported to result in a maintenance free period that is 4 times longer than typical tankless water heaters, which results in up to 20 years of continuous operation.

This particular model reaches up to 3.6 GPM, with the most powerful option in the SioGreen lineup being 4.6 GPM.  Therefore it is suitable for small to medium houses where you could get away with running a shower, kitchen sink and maybe dishwasher at the same time.

Keep in mind that using this as a whole house solution isn’t recommended.  SioGreen have advertised this rightly so as a point of use system, so most users will be installing it for one utility only.

This unit is perfect for this type of application, with a small form factor measuring at 17.5″ * 11.3″ * 3″ and weighing 15 pounds, making it suitable to place under a sink or any other hidden away space you can think of.

Impressively, this model reaches a temperature of 167 °F, which is equally the highest temperature setting on this list, along with the previously mentioned Takagi.  It makes this unit suitable for commercial applications as well, like a super heated dishwasher.

If we had to nit-pick one thing, it would be the temperature display which is in Celsius rather than Fahrenheit.  It’s not a big deal considering the task of adjusting the temperature usually happens only a handful of times.  Still, we think it’s something that could easily be fixed, but for now you’ll just have to convert the temperature as you set it.

So, at the end of the day, is this a tankless water heater worth investing in?  Well considering that it has the efficiency of electricity and a quartz heating element that virtually removes the need for maintenance, our answer is a resounding ‘yes’!  The unique heating element sets the asking price a bit higher than similar performing competition, but you’ll end up saving more money over the longer term due to the minimum maintenance required.

10.  Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater – Comes with ventilation kit

Just like the Rheem model we’ve mentioned, the Eccotemp is another such tankless water heater that is suited for small to medium sized homes.  With a maximum flow rate of 4.8 GPM, you should be able to comfortable run a hot shower and a kitchen faucet at the same time without any issue.

However; the Eccotemp is gas powered meaning you’ll end up having to install vents required to remove the fumes that build up as a result of the heating process.

The dimensions run at 24.75″ * 15.25″ * 6″ which makes it larger than electrical models but still comfortably small enough to fit almost anywhere inside your house.

The controls are fairly straightforward with a knob for the temperature and gas that allows you to tweak the flow and temperature output.  There is also a digital display of the temperature – a nice bonus considering the budget price.

Eccotemp may have provided all that is necessary to get this heater up and running, but when it comes to actually functioning, that’s when it starts missing the mark. 

Despite the reservations, many users have reported positive experiences and it seems like the Eccotemp FVI-12-NG is a hit or miss.  The question is, can you take the risk?  Considering the price, you may decide to give it a go only if you have modest hot water requirements.  Having said all that, we recommend the Rheem RE 13, Titan SCR2 N-120 or SioGreen IR14K220 if a low volume solution is your primary criteria.

Tankless Water Heater Buyer’s Guide

A tankless water heater can turn out to be a pretty big investment.  The costs of just the unit can be upwards of 100’s of dollars and if you add in a professional installation you’ll easily surpass $1000.

It’s extremely important to know your exact requirements before making a buying decision – but how do you go about determining this?

In our guide, we’ll go over all the important factors you need to consider to make your next tankless water heater purchase a worthwhile one.

Determine your flow rate and temperature rise

Ah the flow rate.  We’ve mentioned this all important term many times in this article.  The flow rate, as mentioned previously, is the amount of water that can pass through your tankless water heater whilst being heated.  It’s measured in gallons per minute (GPM).  Most manufactures will give you a minimum flow rate (activation) and a maximum flow rate.

• Minimum/Activation Flow Rate: The activation flow rate is the minimum flow rate required to activate the heating component of the tankless water heater.  This usually ranges from 0.1 – 0.9 GPM.
• Maximum Flow Rate: This is the maximum amount of water that can flow through the unit whilst being heated.  Keep in mind that the maximum flow rate for a device is for the best case scenario.  You see, flow rate is effected by temperature rise.  The temperature rise indicates the temperature level increase that is required to get the incoming water to the temperature you desire.  If the incoming water temperature is high, then a lower temperature rise is required and hence a higher flower rate can be achieved.  The opposite is also true.

If a tankless water heater can’t keep up with the flow rate demanded by your house, you may start noticing cold water coming out of the faucet!  Some units have built in mechanisms to prevent this happening.  In other cases, the manufacturer will recommend an installation of a valve to throttle down the flow rate.

It’s therefore super important to determine your temperature rise and flow rate requirements so you can avoid any nasty surprises.

Ok, now we know this information, how do we go about actually determining the flow rate of the unit we require?

Firstly, you need to determine your maximum GPM requirements.  You may find that at times, several devices may be using hot water at the same time.  Therefore; you can find the maximum GPM by adding their individual flow rates together.  Here is a simple table with the typical GPM value for common household utilities:

Secondly, you need to determine the temperature rise.  Basically, you need to figure out the temperature of the incoming water to your house, and the required temperature you want coming out.  Typical incoming temperature will be around 50 °F (will vary depending on the season and where you live) and output temperature will usually range from 100 °F – 120 °F.  Most tankless water heaters allow for an output in this range, with many exceeding 120 °F.

Here is an example of a calculation:

Let’s say you’ve determined that a standard shower head, bathroom sink and dishwasher may be used at the same time.  Collectively, they require a GPM of 3.5.  You’ve also determined that the inlet water temperature will dip no lower than 45 °F.  You also require an output temperature of 105 °F.

Thus a temperature rise of 60 °F at 3.5 GPM is required.

All manufactures provide this type of information, so it’s crucial that you take a close look at these details before deciding.

Point of use or whole house?

Depending on your requirements, you may opt for either type of installation.  A whole house set-up will connect to your house water inlet to provide warm water for all applications.  A point of use installation will only be suitable for one application at a time (like a sink or shower).

Generally, you’ll find point of use tankless water heaters to be cheaper, less powerful and smaller than whole house units.

There are a couple of scenarios where you would consider point of use over whole house units.  Maybe you have an outdoor utility that requires warm water?  Or perhaps you already have an older tanked unit that you don’t want to get rid of.  Instead, you simply want to supplement it with a tankless unit.  In these cases, a point of use unit will probably be your best bet.

Natural Gas, Propane or Electrical?

There are three main fuel types for tankless water heaters.  Many modern units are powered electrically, but it is also common to find units that run on propane or natural gas.

Electric powered units are significantly more energy efficient but cost more to operate than gas or propane tankless water heaters.  They are generally not as powerful, but this is also heavily dependent on the manufacturer of the model.  A propane fuel source can actually be the most expensive option at first, but they are also extremely effective in their heating ability, making them ideal choices for portable options.

The biggest difference lies in the installation.  Natural gas and propane powered units require ventilation to remove the exhaust let off by the ignition flame.  Ventilation usually goes through the roof (vertical) or through the wall (horizontal).

The easy accessibility (everyone has an electrical outlet) and eco-friendly nature of electrical powered tankless water heaters has made them a very popular choice.  However; you may also find value in gas or propane models if portability or absolute heating power is your primary need.

Professional or DIY installation?

Almost all tankless water heaters that we’ve come across require a professional installation to prevent the warranty from becoming void.

Installations can be quite complex with several questions you need to answer:

• Do you have the correct power requirements?
• Have you determined where you will place the unit?  It’s not so much a question of installing the unit inside or outside as the manufacturer will already advice you of this.  Rather, you need to consider the water line, electric outlets and gas line (if applicable) proximity to the water heater.
• If it’s a natural gas or propane unit, how will you set up the ventilation?

These are just some of the things you need to keep in mind.  Hiring an expert will cost you more money initially, but will potentially save you a lot more money in the long run, especially if your unit fails and you can’t claim the warranty.

Over to you

We hope you enjoyed reading this article as much as we enjoyed writing it!  The best tankless water heaters reviews for 2022 was written to help you decide which tankless water heater is right for you.

We know there are so many options out there that making a decision can be overwhelming and confusing!  Even harder still, making the right decision can almost seem impossible.  We hope we’ve helped push you in the right direction in finding your perfect tankless water heater!

Have any questions or comments?   Feel free to leave them below.