10 Best Tankless Water Heaters: 2019 Expert Review Guide

Are you sick and tired of waiting for hot water when you want a shower?

How many more times are you prepared to run a bath and find the water turns cold before the tub is full?

You don’t need to endure these issues any longer.

Not only will a tankless water heater provide toasty warm water on demand throughout the house, they come with another inbuilt benefit…

Since you won’t be permanently heating water in a storage tank and these heaters are universally energy-efficient, you can notice dramatic savings on your utility bills to ice the cake.

Sound good?

We’ve curated the top 10 models in a glutted market to save you even more time and money so read on to discover which might work best for you…

Eccotemp is a family firm with almost two decades in the trenches. Their stated intention is to provide you with tech-driven kit sharply focused on energy conservation.

The L10 is a highly mobile water heater capable of providing an ample supply of hot water whether you’re camping or otherwise enjoying the great outdoors.

Installation is straightforward. Hang the heater using the bracket included then hook up a 20-pound propane tank. Connect a pair of water hoses then pop in 2 D-cell batteries and hit the switch for a steady stream of hot water.

Despite its slimline dimensions and compact footprint, flow rate is respectable at 2.6 Gallons Per Minute. With no need for extreme pressure, this unit is ideal for use at higher altitude serving you up with water heated between 80F and 40F.

Since the automatic ignition is battery-powered, you’ll get no fire risk with matches eliminated from the equation. Auto shut-off prevents any danger from overheating.

For dependable, consistent and powerful outdoor performance, the rugged L10 punches above its diminutive weight.

PRO

  • Compact travel unit weighing just 27 pounds so perfect for use on your travels
  • Low operating range of 20 to 80 PSI means L10 works well on elevated terrain to 5500 feet
  • Automatic shut-off and battery-powered ignition to maximize safety when you’re outdoors

CONS

  • Not possible to plumb in permanently
  • Unsuitable for use indoors

Portable water heaters have many use cases from hiking or trips in the RV to days by the lake or up in the mountains. Whether you want to wash down your vehicle or take a hot shower, investing in the L50 will make that and much more possible.

If you fancy an invigorating start to the day camping but a cold dip in the lake is too extreme, the showerhead bundled along with a steady stream of hot water is a game-changer.

As an added kicker, you can use a 12-volt pump to build out a tweaked water system. Connecting the L5 to a pressure washer is another outstanding benefit when it’s time to hose down your vehicles.

Operating range is 20 to 80 PSI with flow rate coming in at 1.5 Gallons Per Minute. While weaker than the larger L10, the trade-off is even better portability.

While the L5 is not cut out for permanent installation or heavy punishment, as an occasional and versatile mobile water heater, we’d urge you to pop it on your shortlist.

PRO

  • Battery-operated unit that works well out on the trail or anywhere off-grid calling for nothing but a liquid propane tank
  • All hardware included and installation is a breeze so get going straight out the box
  • Showerhead thrown in making this a versatile, portable outdoor option

CONS

  • Not robust enough for prolonged, sustained use
  • Water flow could be improved

This adaptable tankless water heater is a wise bet for single-family homes where you often use two bathrooms at the same time.

If you live somewhere cooler, the ECO 27 can heat water at the rate of 2.7 Gallons Per Minute. In hotter climates, this unit can easily deal with multiple applications at the same time.

Energy-efficiency is uppermost and the way this appliance intelligently self-modulates can help you halve your water heating costs.

The digital interface is intuitive and allows you to dial in the temperature just the way you like it even if you’re not a tech-lover.

While water heaters are not intended to be ornaments, it doesn’t hurt that the ECO 27 looks sleek, so it won’t spoil the lines of your minimalist bathroom. Build quality is rock-solid so this is not a case of form over function.

If you’re on the hunt for a nimble and highly capable tankless heater to pep up shower time without forcing you to grapple with primitive, imprecise controls, the ECO 27 is a home run on all those counts.

PRO

  • Exceptional flow rate even at low temperatures allows for simultaneous showering
  • Fine-tune temperature digitally in 1-degree increments for precise control
  • Self-modulating unit gives you only the energy you need and could lead to dramatic savings on the cost of heating water

CONS

  • To take advantage of warranty, you’ll need professional installation
  • Maintenance is expensive and customer service less than responsive

Sizeable without eating up too much precious real estate, the Rheem RTGH-95DVLN rolls power, energy-efficiency and on-demand hot water into one poky unit.

The space-saving, flattened design allows you to pop this heater in confined spaces. If you need to house it in the attic, you won’t end up with diminished performance either.

With a water-saving setting and no standing pilot light, you can achieve realistic savings of up to 40%. The rugged copper heat exchange increases lifespan making the Rheem a cost-effective option over time even if the upfront cost is a little steep.

Hot Start programming eliminates those shocking bursts of cold water that can catch you unaware as you start your supposedly hot shower.

A multi-tasking workhorse, you’ll be able to easily supply several appliances with water at the same time. This means there’s no need to wait until the dishwasher is done before heading to the shower.

For on-demand hot water throughout the home in an eco-friendly package meeting all energy standards, the Rheem RTGH-95DVLN might not be cheap but you’ll get an outstanding ROI.

PRO

  • Remarkably energy-efficient unit
  • Installation is straightforward and all components can be replaced if necessary so you won’t need to replace the entire system if anything goes amiss
  • Delivers water to multiple fixtures at the same time with no drop in performance

CONS

  • Can heat slowly when the pressure is ramped up
  • Certainly not the cheapest option at your disposal

Rated at 150,000 BTU, this Rinnai tankless heater works a treat in smaller homes, certified for use in mobile homes, and compact enough to slot into confined spaces.

Don’t think this small footprint means poor performance, though. This propane heater meets NOx Emissions Standards while serving up hot water throughout the house at an impressive 6.6 Gallons Per Minute.

You’ll need to factor in installation and this can be pricey so make sure you scope this out in advance.

Once you’re up and running, you’ll enjoy a steady stream of hot water on tap with a wide temperature band of 98F to 140F catering for most reasonable needs.

Whether you want hot water for your smaller family home, mobile home or an apartment, this dinky little Rinnai delivers outstanding flow married to consistent temperature in one easily navigable unit.

PRO

  • Space-saving tankless heater that packs a serious kick with robust flow and hot water on demand across multiple applications
  • Lock temperature in to eliminate those unwanted bursts of cold spoiling your morning shower
  • User-friendly operation with crisp, clear LCD display for temperature control

CONS

  • Some annual maintenance required but it’s affordable and non-invasive
  • While marketed easy to install, the cost of setup can be high

If you’re looking for a cheap tankless water heater, the Rinnai Ultra Series is not for you. If, on the other hand, you want a connected appliance to drop into your automated home and you prize performance above budget, this model is the obvious solution.

Condensing technology bleeds even more energy saving from this natural gas model which is already 95% thermal-efficient.

You can tweak the temperature or activate recirculation remotely using your smartphone assuming you have a WiFi network at home.

Rinnai’s proprietary Circ-Logic Technology helps slash waiting time for hot water if you use an external pump.

When used in the home, temperature range spans 98F to 140F. Although you can adapt this heater for commercial use, this requires a dedicated controller and other add-ons available separately. In return, the maximum temperature increases to 185F.

If you can weather the stiff sticker price and spring for professional installation, this tankless heater is among the pick of the bunch.

PRO

  • WiFi-enabled for remote monitoring so an ideal addition to your smart home
  • Robust enough for light commercial applications and more than capable of supplying your home with all the hot water you need whenever you need it
  • Low NOx emissions and slimline form makes this a great candidate for indoor installation

CONS

  • Priced significantly higher than most of the competition
  • Enforced professional installation further increases the investment needed

A flawed gem, the RL75iN from Rinnai is a tankless heater capable of churning out hot water across several applications at a respectable flow rate.

At 82% thermal efficiency, you won’t get quite the energy saving potential as the Ultra Series above offers, but running costs are still low. You won’t need to lash out for installation either and all the kit you need along with comprehensive instructions comes in the box.

A baked-in temperature system takes the legwork out of regulating the heat exchange. It will also ensure hot water is delivered efficiently and on-demand without running you too much when the monthly bill hits the mat.

This heater fits neatly in any room as long as you angle the vent toward the outside. It’s unsuitable for outdoor use.

Hard water can lead to scale building up and impairing operation. Luckily, a digital meter lets you know if this becomes a problem so you can take action before too much damage is inflicted.

For a cost-effective and eco-friendly water heater that’s GSA-approved and meets all emissions standards, this Rinnai is well worth your further investigation.

PRO

  • With a maximum flow rate of 7.5 GPM, you can feed a sink and pair of showers simultaneously
  • Easy install with all mounting hardware included reducing overall costs
  • Integrated alert to inform you if scale is accumulating so you can take preventive measures

CONS

  • Temperature of water contingent on flow which is disappointing
  • A relatively volatile unit, you might experience some teething problems and servicing is complex

This natural gas heater from Rinnai falls in line with Texas and California NOx standards for emissions while it also comes fully approved by pollution agency SCAQMD.

Another WiFi-enabled heater, you can enjoy remote access as with other tech-driven Rinnai models.

As long as you can handle the heavy weight, the unit is small enough to install in more confined spaces. You could place it in an attic or crawl space without adversely impacting performance.

Powered by natural gas, you can realize substantial savings on your utility bills meaning you’ll get a worthwhile return on investment along with consistent hot water on demand.

Temperature lock and enhanced scale protection are nice extra touches.

While the heat exchange is covered for 10 years and other parts for 5 years, Rinnai only offer a 1-year commitment to labor which is less than ideal.

Capable of supplying endless hot water at the rate of 6.5 Gallons Per Minute, this model is not particularly cheap but offers excellent overall value if you’ve got a fluid budget and exacting standards.

PRO

  • Eliminate downtime since this heater serves multiple fixtures simultaneously and save money as well through outstanding energy-efficiency
  • Requires precious little space for installation without compromising performance
  • Take charge remotely using WiFi and your smartphone

CONS

  • Surprisingly heavy considered its compact form
  • Labor guarantee offers just 1 year’s coverage

In business for close to a century, the family firm Stiebel Eltron continues to supply precision-engineered water heating solutions from Europe to the US.

Hitting an exceptional 99% energy efficiency, this heater is an example of German engineering at its finest. You can expect to reduce your energy bill but up to 20% meaning you could recoup some of the considerable cost by way of ongoing savings.

The digital display gives you a clear indication of output and you’ll get a tech-laden appliance that’s nevertheless a cinch to use.

Stiebel Eltron pride themselves on Tempra Advanced Flow Control. This was invented by the company founder and ensures that water flow is automatically regulated in line with your requirements streamlining operation wonderfully.

If you’re looking for the optimum meeting point of technology and user-friendliness, the Tempra 24 is a must.

PRO

  • No venting whatsoever required and the heater is small enough to install just about anywhere for further versatility
  • Proprietary Advanced Flow modulates water supply so even if you’re pushing the system too hard, you won’t be surprised with cold water
  • Whisper-quiet in operation so no annoying hum

CONS

  • Incoming water needs to be at sufficient temperature
  • While marketed as “cheap and easy”, installation can actually be fairly costly

Takagi’s range of tankless water heaters is broad and deep. This 6.6 GPM model is a neat fit if you’ve got a smaller home with no more than 2 bathrooms to service.

This heater works best in more temperate climates and it can service a pair of showers dependent on the heat of incoming water. You can benefit from a direct or indirect supply. You’ll also have the ability to send water to heated flooring systems.

To help with combustion, the AFR sensor makes certain that air and fuel are correctly proportioned. An onboard computer manipulates the fan speed so emissions are slashed while efficiency is boosted.

To avoid the need to constantly head to the heater, a neat remote control comes included.

Some practical knowledge and experience is assumed for installation so this is not a simple plug-and-play appliance if you don’t know what you’re doing.

With a healthy warranty on parts and the heat exchanger along with superb build quality and innovative tech baked in, this Takagi is a dependable addition to your home.

PRO

  • Sensor and onboard computer combine to ensure air/fuel ratio are always optimized
  • Freeze protection protects this unit in cooler climates although it does work better in warmer environments
  • Class-leading 15-year warranty on heat exchanger

CONS

  • Specific stainless steel venting required
  • Not suitable for homes with more than 2 bathrooms

Conclusion

t’s a tough call to establish an overall winner from this selection since they cater for different needs.

If pushed to choose just one, the Rinnai RL75iN gets our vote. This 7.5 GPM model is a winning sweet spot of power, efficiency and versatility. It’s also super-simple to install and small enough to mount in confined areas.

Get in touch if you need assistance with any aspect of your buying decision and be sure to check out our comprehensive breakdown of tankless water heaters by brand if you can’t find exactly what you’re looking for right here.

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