Best Tankless Water Heater Reviews: An Extensive Guide

Best Tankless Water Heater Reviews: An Extensive Guide

An ENERGY STAR certified tankless water heater uses approximately 30% less energy on average, when compared to a traditional tank hot water heater.

Benefits

  • Average 30% energy/gas savings compared to a tank hot water heaters
  • Endless and instant hot water supply – doesn’t run out like tank water heaters
  • Compact = saves a lot of space
  • Lasts 5 – 10 years longer than tank water heaters

Tankless water heaters provide a continuous supply of hot water on demand as needed, thus do not require a storage tank. They usually hang on the wall and come in a few different types such as electric, propane or gas, depending on what your energy set up is at your home. Tank heaters use significantly more energy as hot water is stored in the tank, it needs to continuously heat this stored water so it’s ready to go when you need it

How does a tankless water heating system work?

high money warranty heaters savings buyA tankless water system works by heating water directly as it is needed on demand. Water comes into the unit and is heated by a heating exchanger (element) which is also activated on demand. Electric units use coils while a gas/propane unit has a burner that heats the flowing water.

Gas/propane units usually have larger and better heating capacities than electric units, thus bigger whole-home units are mostly of the gas/propane variety.

Gas (natural gas or propane) vs. Electric

This depends on what setup you already have at your home, will determine what type of tankless water heater you will need. The main types are natural gas, propane, and electric units. If you do not have a gas line, it may be best to go with an electric model as it would be expensive due to additional setup and installation costs for that particular fuel type. If you happen to have both options available to you, the following are the advantages and disadvantages of each

Gas & Propane powered

Advantages:

  • More powerful – best for mid to larger homes
  • Cheaper to run than electricity usually
  • Best for cold regions

Disadvantages:

  • Units are more expensive to purchase
  • Gives off emissions
  • Requires ventilation

Electric

Advantages:

  • Best for small homes or an apartment
  • Best for warmer regions
  • Slightly small than gas powered units
  • More affordable than gas powered units
  • Does not give off emissions
  • Does not require ventilation

Disadvantages:

  • Mid to larger homes would need multiple units to provide the same amount as a gas powered one
  • Heater elements need more maintenance due to mineral buildup
  • Electricity is usually more expensive than gas or propane
  • Multiple electric tankless heaters have the same output as one gas powered unit

Table of our Top Picks

NameSizePower TypePrice
Rinnai Luxury Series9.4 GPMGas Indoor / Outdoor
Propane Indoor / Outdoor
7.5 GPMGas Indoor / Outdoor
Propane Indoor / Outdoor
Rinnai Value Series6.6 GPMGas Indoor / Outdoor
Propane Indoor / Outdoor
Ecosmart6 GPMElectric View price
4.6 GPMElectric View price
Rheem Performance5.3 GPMElectric View price

Best Tankless Water Heater Reviews by Category

Gas Tankless Water Heaters

Rinnai Luxury 9.4 GPM Series

high warranty money heaters buy rating designThis is one of the highest output non-condensing units available. With superior efficiency to meet the heavy demand of larger homes. This line is available in an outdoor and indoor version to meet you needs or preference. The Luxury model has an energy factor of 0.82 (82%) and comes with built-in recirculation tech for quicker hot water delivery. You can read our detailed review here.

View Price – Outdoor  View Price – Indoor
ProsCons
• ideal for larger homes / heavy demand
• recirculation technology for quicker hot water
• weather resistant
• venting kit not included with indoor version
• if you have an unusually big home you may need a second unit

Rinnai Luxury 7.5 GPM Series

design control save higher brands heatersThis is the sister model to the unit above, but made for mid to large homes. The Luxury 7.5 GPM line comes an energy factor of 0.82 (82%), and also comes in a weather resistant outdoor and indoor version as well to meet your needs or preferences. It also has the same recirculation tech so as to deliver hot water quicker. Our full review can be found here.

View Price – Outdoor  View Price – Indoor
ProsCons
• Ideal for mid-larger homes/mid-high demand
• recirculation technology
• weather resistant
• venting kit not included with indoor version

Rinnai Value 6.6 GPM Series

brands higher save control rating heaters money highThe Value series is the perfect combination of value and efficiency in a compact unit. This line offers the same reliability from Rinnai in a model perfect for small to mid size families. This line is just as efficient with a energy factor of 0.82 (82%), and also comes in indoor and weather resistant outdoor models for your preference. Our full review can be found here.

View Price – Outdoor  View Price – Indoor
ProsCons
• Ideal small-mid size families/low-mid demand that’s perfect for warmer regions
• weather resistant
• venting kit not included with indoor version
• does not have recirculation technology

Rinnai Ultra Series 8 GPM

Condensing & recirculation tech make it one of the most energy efficient available with an energy factor of 0.96 (96%). Our full review can be found here.

  • Comes with two heat exchanges for maximum performance
  • Energy star certified
  • Outdoor version only (weather resistant)
View Price

Best Propane Tankless Water Heaters

Rinnai Luxury Series 9.4 GPM

warranty save heatersOne of the larger highest output non-condensing units available. This is a high efficiency tankless hot water heater to meet the heavy demand of bigger families. It is available in an outdoor and indoor version to meet your needs. The Luxury model has an energy factor of 0.82 (82%) and comes with built-in recirculation tech for faster hot water delivery… (full review).

View Price – Outdoor  View Price – Indoor
ProsCons
• Perfect for big families / heavy demand
• recirculation technology for faster hot water
• weather resistant outdoor version
• venting kit not included with indoor version
• if you have an unusually big home you may need a second unit

Rinnai Luxury 7.5 GPM Series

warranty gas water heatersA sister model to the unit above, but made for mid to large families. The Luxury 7.5 GPM comes in at an energy factor of 0.82 (82%), and also comes in a weather resistant outdoor version and a indoor version too. It also has the same recirculation tech to deliver hot water faster… (full review).

View Price – Outdoor  View Price – Indoor
ProsCons
• Perfect for mid-larger homes / mid-high demand
• recirculation technology
• weather resistant outside model
• indoor version does not come with a ventilation kit

Rinnai Value Series 6.6 GPM

best tankless water heaters gas water heatersThe Value series is a less expensive option that is the perfect combination of value and efficiency in a compact unit. It offers the same reliability in a model for small to mid sized families. This is just as efficient as the Luxury model, with a energy factor of 0.82 (82%), and also comes in indoor and weather resistant outdoor models for your preference… (full review).

View Price – Outdoor  View Price – Indoor
ProsCons
• Perfect for small-mid sized houses / low-mid demand
• weather resistant outside model
• indoor version does not come with a ventilation kit
• does not have recirculation technology

Another great pick

Rinnai Ultra Series 9.8 GPM & 8.0 GPM

Condensing & recirculation tech make it one of the most energy efficient available with an energy factor of 0.96 (96%). Full review can be found here.

  • Comes with two heat exchanges for maximum performance
  • Energy star certified
  • Outdoor version only (weather resistant)
View Price – 9.8 GPM / View Price – 8.0 GPM

Best Electric Tankless Water Heaters

EcoSmart 6 GPM (36 kW 240-Volt)

water heatersA good value model that provides 6 GPM – suitable for small houses, apartments or summer cottages. This model is estimated to use approximately 30% less energy when compared to your standard water heaters. This model requires a dedicated 150 amp / 4 x 40 amp double pole breakers… (full review).

View Price
ProsCons
• Ideal for small houses or apartments
• self-modulating technology that saves energy
• easy to replace heater elements
• does not need a vent because it’s electric
• not suitable for medium-larger demand, or houses in colder regions

Rheem Performance 5.3 GPM (27 kw)

water heatersThis unit is from Rheem’s Performance series and has an output of 5.3 GPM, ideal for smaller houses and apartments. This model is great for those who want continuous hot water while reducing and saving energy when compared to your standard heater. This model requires 3 x 40 amp double pole breakers… (full review).

View Price
ProsCons
• Ideal for small houses or apartments
• self-modulating technology that saves energy
• easy to replace heater elements
• no vent needed because it’s electric
• not suitable for medium-larger demand

EcoSmart 4.6 GPM (24 kW 240-Volt)

Slightly smaller than the one mentioned above, this model provides 4.6 GPM – ideal for small homes, apartments or summer cottages, especially those in warmer climates. This model is perfect for low demand endless hot water. This model requires dedicated 3 x 40 amp double pole breakers… (full review).

View Price
ProsCons
• Ideal for small houses or apartments
• self-modulating technology that saves energy
• easy to replace heater elements
• no ventilation required
• not suitable for medium-larger homes with medium-higher demand

Buying Guide

What you need to consider

  • The volume or amount of water the heater needs to heat as water flows through it – this is flow rate and is measured in gallons per minute (GPM)
  • The desired temperature the unit can achieve
  • The temperature of the cold water flowing into the unit

How to find the proper tankless water heater for your home

Size / flow rate

First we need to determine how much the singular fixtures use in your home, and then add them up to figure out how much you will need for high demand times (such as getting ready in the morning), this ensures you’ll have plenty at your busiest times without going beyond what your unit is capable of.

FixtureAmount (GPM)
Sink1 – 2
Shower2 – 3
Bathtub3 – 4
Washing Machine2
Dishwasher1.5 – 2

Home SizeBathroomsAvg Demand
Apartment13-4 GPM
Small Home14 – 5 GPM
Avg Home26-8 GPM
Large Home3+8-10+ GPM

Determine your temperature rise

Depending on your climate, this will dictate what type of tankless water heater you should get. Keep in mind what set up you already have in your home – whether you have gas lines installed or not as this can be an additional cost.

Electric units are able to warm the water approximately 30 degrees. Electric units are suitable for those who live in warmer climates such as in the southern US. They are also suitable for summer cottages or small vacation homes.

Gas fired units are more powerful and are able to easily warm the water 50+ degrees. These units are best for those living in colder climates such as the northern US/Canada – so you are able to have hot water year round.

FAQ

I can’t decide between an electric or gas tankless water heater

Gas and electric tankless are suitable for apartments, condos, cottages, and small to mid size homes. Larger homes should keep to gas only as they’re more powerful.

best tankless water heatersElectric units are not as powerful as gas & propane, usually they put out at most about 5 gallons per minute which is enough to run a shower and a washer at the same time in some climates.

Gas & propane units are much stronger and can handle heavier demands with ease which makes them great for larger homes. Although gas models are more expensive to purchase upfront, they have condensing tech which means they’re twice as energy efficient than electric models – so in the end it’s without a doubt the best value and the smart choice.

It comes down to your homes heat and power system. Does it run on electric? Do you have gas/propane hookups or lines? Whatever you current set up is likely the easiest to go with.

Can hard water and scale damage my tankless water heater?

Yes, it certainly can and is most often the reason why tankless water heaters need to be replaced. Hard water and scale over time will coat and clog the heating elements and internal running parts in your tankless heater. This is cause your unit to eventually burn out and will damage it, if left unmaintained.

Check the water hardness at your home, and definitely make sure you clean and treat your tankless water heater every 6 months to a year to steer clear of this.

Where can I find out the hardness of my water?

You can always call your town office for this information – they may offer you a home testing kit or you can purchase one yourself. You may also check out this map for water hardness in different areas of the United States.

How long will a tankless water heater last?

With proper installation and cleaning maintenance every so often to prevent hard water damage, a tankless water heater will last 15-25 years which is significantly longer than your standard heater.

How hot can the water get?

Normally it can get up to 140 degrees and usually the default setting is at 120 degrees. As you shop around you can find in the model specs how hot it can get. Most if not all models have computer controlled systems that can be set at to your desired temperature.

Why do I need electric power for my propane/gas tankless unit?

Even though your model is gas or propane powered, your unit should have a standard electric plug in. This is because these particular models have a small electric motor inside to power the forced air blower for the exhaust to ventilate outside. A minimal amount of electricity is required for the digital remote, circuit board, and electric ignition so it can be turned on demand, rather than having a pilot light burning constantly – even when not in use. The actual electric draw for these is minimal.

Will I have instant hot water with a tankless heater?

A tankless water heater will heat water on demand, instantly – but you need to understand regardless if you have a tank or tankless unit, it does take time for the water to move from the heater itself through the piping in your home to the faucet/fixture you’re at. Many people expect hot water as soon as they turn on the tap, but forget this fact that their tankless unit does need to fire up and start heating water as needed. Many tankless models do have recirculation tech for faster hot water delivery, so that’s definitely something to look for when shopping around.best tankless water heaters

What is the hot water temperature on average for washing hands, showering and baths?

Usually good warm water for a shower or bath is around 95 – 110 degrees.

Do I have to turn the tap all the way to activate hot water?

No, the flow rate for all models is very low so there is no need.

What kind of venting is required?

For an electric type of unit, none. For a gas fired model, it depends on if it’s an outdoor and indoor version.

Outdoor: Direct vent as it’s already outside, so it will ventilate naturally.

Indoor: Will need a special set up to be ventilated outside as to avoid filling your home with exhaust.

User Reviews

« I am retired from the Gas Company and had hundreds of service calls for for tankless water problems but never for a Rinnai tankless. I now own 2 Rinnai tankless water heaters and am very pleased with them. »

« We’ve had our tankless water heater for 3 months. We love that we have never had to worry if we would have enough hot water. As with or previous electric tank water heater, you do have to wait for the water to warm up, because we chose not to have a recirculating line installed, but it’s not a long wait. It’s only raised our gas bill about $10, but our electric dropped $25. Definitely worth the money. »

« I was apprehensive about switching to a tankless hot water heater. We eliminated two 20 year old 50 gallon units with one Rinnai tankless unit. Never runs out of hot water even when multiple showers and appliances are operating. »

« The water is hot right away, even when my son wants a really hot shower and turns the temp up. It is easy to turn up, then back down to the temp I like. I have been in my home about 2 months and my gas bill is less than half. »

« Had my Rinnai Tankless water heater now 6 months. Very pleased. Consistent hot water with 2 teenagers in house. No regrets from switching from tank. »

« I replaced my electric tankless with a propane model from Rinnai and it’s already paid for itself within a year in my home.»

« Unlimited hot water is the best feature. My gas bill is low and so is my electric since upgrading to a tankless water system. Worth every penny!! »

« So far the Rinnai has been great. No more cold water during back to back showers and no more leaks in my attic from the old tank. Just preventing insurance claims and repairs is enough to make me happy.»

« Due to the removal of our tanks and placement out doors of the units there is a lag in getting hot water but getting two storage closets back is great »

« Meets our need for hot water even when we have a full house of guests. The only slight negative is it takes a little longer to get hot water than our old water heater. However, we have never run out of hot water, even with two clothes washers, dishwasher and two showers going »

« old tankless had served us well but i didn’t know how much better the rinnai would be. not only do we have hotter water quicker but also at a greater gallon per minute. we are more than satisfied. thank you »

« I’ve had my unit for about half a year and have saved about fifty bucks monthly on power. »

« I’m very happy with my tankless water heater. I was spoiled because i had one installed in my old house a number of years ago. Probably about 5 years ago and was still going strong when we moved. »

« I chose an outdoor model so I’ve got some space back in my garage. After having two regular heaters leak and damage my home, I’m very happy that can never happen with this one. »

« Only had for a few months and have already seen my power bill go down over a third of what it was. »

« I have a jacuzzi and it’s the first time I’ve been able to fill it completely with hot water. It also got rid of that big water heater in my laundry room giving me a lot more space »

« We have nasty well water & now that we don’t have a tank cooking the minerals, the water is much better! This is a 2nd home, so only using propane on demand is a real cost saver. »

« We installed a Rinnai at our old home, for endless hot water and to gain space in the pantry and we loved. We moved into our home with a electric tank heater and the first shower was awful. I immediately went to our gas company and bought a Rinnai. I wouldn’t have a house without one. »

« This is the third tankless water heater we have had. Wouldn’t go any other way! One was installed as a replacement/upgrade, the other two installed in new construction. Fabulous product! »

« We were one of the first to install a tankless water heater 30 years ago. The newer Rinnai tankless water heater is so superior to the older tech. It handles a shower and dishwashers and washing machines without leaving you in a cold shower. No problem running out. Takes up far less space compared to the old tankless water heaters. »

« 4 water heaters in 20 years. No more! Tank leaks always occur just out of warranty. Had a talk with a life long friend who owns and operates a HVAC company. He suggested I consider a Rinnai. After researching, and a few follow-up questions, I took the leap. Best advice I’ve received in many years. This unit saved a bunch of space. It’s virtually silent. My biggest concern….would there be a time lag waiting for it to produce hot water was totally blown away. I timed how long it took hot water to get to my farthest faucet before the old tank type heater was removed. Did the same test with the Rinnai. I don’t know how they do it, but the wait time was identical. I’m loving the fact that I no longer need to think about running out of hot water because of back-to-back showers, clothes washer or a dishwasher competing during a shower. »

« We purchased our first home last year and it is an older home. We knew we were going to have to replace the existing water heater. We didn’t hesitate to look into more efficient and quality products. We are so pleased with our decision to go tankless. We knew that this investment was not only practical but also a necessary need for making our older home more efficient. I would recommend a tankless unit to anyone who is considering upgrading or replacing their existing water heater. »

« Clean quiet water for as long as I need it. We’ve had 3 showers running at the same time a number of times and no lack of hot water. The water heaters (yes, 2 of them) that failed were electric and costly to run. I bought this one Rinnai to replace both of them and it works great. My electric bill dropped by over $100 while my gas barely notched up. »

« We replaced the electric water heater in our former home with a Rinnai heater in 2005. Our monthly electric bill was immediately reduced by 1/3 and there was no appreciable increase in our propane usage. We built a garage with an apartment above it and installed a Rinnai there as well which is perfect for a housing unit where it is only occupied occasionally. No waste of electricity or gas heating water when hot water is not needed. It was a no brainer to install two Rinnai units in our current six bedroom house. One handles the master bath and laundry room. The other handles the kitchen and the five generally unoccupied guest bedrooms. As empty-nesters with kids who visit occasionally this is an ideal configuration. »

Summary
Article Name
Best Tankless Hot Water Heater: Buyers Guide & Reviews
Description
Find out which type of tankless water heater is best for your home. Our comprehensive guide uncovers the most reliable gas, propane and electric models.
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Publisher Name
Quayle Co
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