Tankless Water Heaters Reviews, Costs, Prices, & Comparisons

Tankless Vs Tank Water Heater

Should you buy a Tankless Water Heater?  Your complete guide to Tankless Water Heating. Reviews, pricing, and FAQ all here for you…

Tankless water heaters are increasing in popularity year after year. Although they can sometimes cost more than traditional tank style water heaters, they deliver many features and benefits that conventional tanks are incapable of providing.

The real question is; “Are tankless water heaters worth the extra cost?” Do you really save energy and money in the long run? Are they more than just a craze? Are there other factors that should influence your decision in purchasing one?

First, we’ll explain what makes tankless water heaters different, then explore their pros and cons relative to tank-style storage water heaters. Lastly, we’ll review some of the top selling models today so that you can make a more informed choice between them, if you do end up opting for a tankless water heater.

What exactly is a tankless water heater, and how do they work?

Tankless water heaters, also called ‘on demand’ water heaters, essentially work by rapidly heating water as it flows into the unit and directing it to your hot water taps rather than using a relatively slow heating process to keep a 40-60 gallon tank of water constantly hot (as traditional tank-style water heaters do).

A tankless water heater might heat the water using electricity, natural gas, or even propane, depending on the model. Gas models are typically the most efficient and inexpensive to run but they will require more extensive procedures to install and vent.

Tankless water heaters are typically more energy efficient than tanked water heaters, because there is no large tank of hot water to constantly lose heat when it is not in use (this is called ‘standby energy loss’). They also take up substantially less space than a tanked water heater, which might be the size of a small refrigerator. Lastly, Tankless water heaters typically have a service life that is 10 years longer than a tanked heater.

On the other hand, a tankless water heater can only supply so much water at a time – often between 2 and 5 gallons per minute (GPM) and almost never more than 9 or 10 GPM. By contrast, a tanked water heater may have 60 or more gallons of piping hot water ready to deal with the whole family’s needs in the morning. Tankless models can sometimes cost 2-3 times as much as a tanked model of equal caliber. Gas-powered tankless heaters can demand higher gas flow than most other gas-powered home appliances, and your existing gas supply may not be able to cope without necessary gas line upgrades. Newer tankless units don’t require upgraded gas lines, however, some older models still do.

Another factor that will be very important to some buyers (and not at all to others) is the fact that an on-demand water heater gives your home a substantially smaller carbon-footprint.

How do tankless water heaters compare to traditional models?

In the modern day, it isn’t surprising that the idea of keeping a constantly heated, refrigerator-sized tank of water in your garage or basement might seem inefficient. However, tankless systems do have a few drawbacks. In this section, we’ll look at the advantages and disadvantages of a tankless system in detail. This should help you see whether a tankless system would actually suit your home and lifestyle better than an old-fashioned water heater.

The advantages of a tankless water heater

  • Lower operating costs and reduced energy consumption

This is one of the first things most homeowners consider when they look at a water heater system. Some are more concerned with lowering their carbon footprint. Others simply want to lower their monthly bills. Most of us probably fall somewhere in between.

The good news is that they really are less expensive to operate – so much so that they usually ‘pay for themselves’ fairly quickly. Because you aren’t constantly heating that big tank of water (just to have it cool when you don’t use it), you don’t spend electricity, gas or propane on what amounts to a really inefficient tank style water heater.

  • Longer Lifespan

Most storage water heaters will only last you 7-10 years. Of course, this varies from manufacturer and model, but it is a good average. On the other hand, tankless, ‘on demand’ water heaters can be expected to last around 20 years, perhaps longer. Not only does that effectively cut the purchase and installation price of a tankless heater nearly in half, it saves you a lot of worry about when your heater is going to fail – at least for another decade or so.

  • Smaller Space Requirements

A traditional storage water heater can easily be 5 feet tall by 2 feet across, or even more. As more and more homes seek to gain a bit of extra living space in their garage, basement, or closet, this is a lot of real estate to devote to hot water.

A tankless water heater, by comparison, is typically wall-mounted, so it takes up no floor space at all. A typical unit might be less than 30” tall, 20” wide and 10” deep. Additionally, tankless water heaters are compact enough to fit into small closets or nooks.

The disadvantages of tankless water heaters

  • Reduced volume of hot water output

Though this varies from model to model, tankless water heaters cannot ‘pump out’ as much hot water in a short time as a storage tank-based system. A water heater with a tank can generally keep up with a family taking showers in 2 different bathrooms, doing a load of laundry and washing last night’s dishes at once – for a while, anyway.

A tankless unit, however, never “runs out of hot water,” but can only deliver hot water according to its “Gallon Per Minute” flow rate.  This means, if you purchase a tankless water heater that can only deliver 5GPM (gallons per minute), you won’t be able to run more than one or two taps at once.  Most shower heads release 2.5 to 3.0 GPM of water.  A typical faucet delivers 1.5 GPM of water. A tub faucet usually flows at 4 GPM.  As you can see, 5GPM can get used up rather quickly.

Some very important insight you should be aware of before examining the GPM flow rate of your tankless water heater- is the incoming water temperature. Most tankless water heater manufactures, advertise a GPM flow rate when the home’s incoming water temperature is warm. If a tankless water heater can deliver 5GPM of hot water when the incoming water temperature is 70 degrees Fahrenheit, what happens when your water supply is only 30 degrees Fahrenheit?  Always look beyond the advertised GPM flow rate. Find out the capabilities of the tankless water heater when the incoming water temperature is colder in the winter months.

  • Higher purchase cost

Simply put, tankless water heaters cost more to buy. You can probably find a basic tank heater for $300-400, though you can easily spend $1000 or more. Tankless water heaters really start at around $1000 and go up from there.

This cost is offset by the fact that tankless units last nearly twice as long and cost a lot less to run, but if you don’t have the extra $600, the decision may already be made.

It is also worth noting that most gas-powered on-demand water heaters are eligible for a tax-credit of as much as $300 when you purchase one, making their initial cost that much more competitive.

  • Higher instantaneous energy requirement

This really only applies to gas or propane-powered tankless water heaters.

The problem is that if your home is on a lower-pressure gas main, a tankless heater may not work at all. A storage water heater might draw as little as 30,000 BTU worth of gas as it fills and begins heating your tank. They heat slowly (as the last person to shower in the morning can tell you) but that means they draw less gas at any one time. A tankless unit heats water instantly, and therefore can draw as much as 200,000 BTU worth of gas for as long as it is supplying water.

If your gas main can’t supply that volume, a tankless heater probably won’t operate at all. If you choose an electric unit, your home will most likely need an electrical wiring upgrade. This is due, to the electric tankless models needing more electric power to heat the water. Be prepared to pay quite a bit for that power upgrade with an electric whole house tankless water heater.   

How long does a gas tankless water heater last?

You can expect a tankless water heater as a whole to last at least 20 years, maybe longer. This is a sharp contrast to traditional storage water heaters, which typically last 7-10 years before they need to be replaced.

In addition, you will rarely need to replace a tankless water heater entirely when it does fail. Most of their parts are easily replaceable, which can extend their useful life substantially at much less cost than replacement.

What does it cost to install a tankless water heater?

This is one of those ‘it depends’ answers. The average install cost of a tankless water heater is $1689.00. This doesn’t include the unit itself, however, it does include pickup, delivery, disposal of the existing water heater, all installation materials, and labor.  Generally, tankless water heaters take 6-10 hours to install.

Some home owners even manage the installation themselves (check your local regulations, this may not be legal in your area).

Of course, these prices are for ‘best case scenarios’, and based on overall national cost averages. If conditions are somehow difficult or unique, you may pay more or less for your installation.

What type of savings should I receive from a tankless unit?

According to Energy.gov (https://energy.gov/energysaver/tankless-or-demand-type-water-heaters) families that use 41 gallons of hot water per day or less using a single, central tankless water heater can spend 24% to 34% less to heat their water every year than those using a tanked heater. Homes with a very high hot water use – 80 to 90 gallons per day on average – save a bit less, but still can expect to pay 8% to 10% less to heat their water.

It should be noted that it is not ideal to use a single, central tankless water heater in larger homes. Installing a separate, smaller tankless water heater in each bathroom or laundry room can result in much higher savings – as much as 50% less spent on heating your water – because no heat is lost moving the hot water through pipes to different parts of your home. Alternatively, two tankless water heater units can be installed in line with each other to supply sufficient hot water in larger homes.

Is a tankless water heater worth the cost?

Not in every case. However, in the long run, and for most home owners, yes.

A tankless water heater costs more to buy, and just as much (if not more) to install as a standby-type water heater. However, they cost substantially less to run than standby heaters, and they can last twice as long. Almost any household will spend less with an on-demand water heater in the long run, but that run might be too long for some buyers.

Many homeowners and property investors won’t even own the home by the time that super-efficient tankless water heater pays for itself. Of course, that added efficiency can increase the sale price of the home to compensate.

Some homes are very differently situated than others. If you don’t have a high-capacity gas connection, you could get the gas main upgraded. However, that would make the total cost of installing a gas-powered tankless water heater very expensive indeed!

Lastly, you simply might not have access to a few thousand dollars to purchase and install a tankless water heater. If you simply don’t have (or don’t care to spend) the money, a tankless, on-demand water heater won’t be for you.

So the real question is whether you intend to be around long enough to make your money back on the system. If so, than it is probably a good investment for most home owners.

Which tankless water heater is the best for me?

Of course, there is no one single best make or model for all homes and all needs. However, we’ve reviewed some of the best on the market today below, which should help you select the model which is the best for your unique situation.

Rheem RTE 13 Electric On Demand Water Heater

Rheem’s RTE 13 is a very popular model, and is by far the top seller on Amazon. It has a fairly low output, but its other features make it an excellent choice for single-bathroom homes, or even 2 bathroom dwellings if they have been fitted with low-volume shower heads.

Pros for the Rheem RTE13:

  • Price

This is a very affordable unit, and as an electric model it is relatively inexpensive to install. Most buyers confirm that the savings in their monthly power bills repay the cost of the unit in 2 years or less.

  • Size

This unit is particularly compact, making it ideal for smaller homes or anywhere space is tight. It can easily be hidden inside a cabinet, and will actually fit under most sinks.

Cons for the Rheem RTE 13:

  • Low output

4 GPM is not very much, and is plainly too small for larger homes with multiple bathrooms. That being said, it is a very high output for the price of the unit.

  • Issues in colder climates

The RTE 13 can struggle to put out even those 4 GPM if the water coming in to the unit is particularly cold. Expect performance issue in northern winters.


This is a very inexpensive unit, with a decent output for its price range. It is a good choice for small homes and apartments, but will struggle with larger, multi-bathroom homes, especially in cold climates. It is also admirably tiny.

Overall, it is easy to see why this unit is so popular.

Ecosmart ECO 27 Electric On Demand Water Heater

Ecosmart’s ECO 27 is an excellent buy. It is powerful for its size, and excels at providing hot water in demand, even for larger homes or small-to-medium homes in cold climates.

Pros for the ECO 27:

    • High output

This model works very well in the cold, and can put out an impressive volume of hot water in warmer regions and seasons. Even when the water comes into the unit at a bone-chilling 32F, it manages a steady 3 GPM.

It easily manages 6 GPM with a warmer input, which is plenty to run 2 showers at once.

    • Lifetime warranty

The heater itself bears a lifetime warranty, which is fully transferrable between owners. This makes it a handy boost to the resale value of the home.

    • Low cost

It has a fairly low purchase price, and actually runs more efficiently than the Rheem 13 above, thanks to its ‘self-modulating’ technology.

Cons of the ECO27:

    • Variable performance

A substantial number of users note that their unit does not live up to expectations, either in GPM or performance in the cold. It is possible there are some quality control issues in the manufacturing process.

    • Poor customer service

Some owners report poor customer service, and there is a great deal of fine print in that lifetime warranty.


Low price, good performance (usually) and a lifetime warranty make this an excellent choice for larger homes in warm climates, or medium sized homes even in the cold.

Takagi T-KJr2-IN-NG Natural Gas On Demand Water Heater

The T-KJr2-IN-NG, despite the alphabet soup of a name, gets excellent reviews, and works very well for households of as many as 5 people, regardless of climate. It is also competitively priced for a medium-sized unit. It supports an optional remote control, available separately.

Pros of the T-KJr2-IN-NG:

    • Very efficient

This unit has a similar efficiency to the ECO27 above, but at a higher output.

    • Very reliable

This unit performs very well, and requires relatively few servicings or repairs. It is perhaps the most reliable heater reviewed here.

Cons of the T-KJr2-IN-NG:

    • High initial cost

This is a rather pricy model, and installation costs for gas-fired tankless water heaters are higher than for electric models as well.

    • Mid-level power

Though it is in a different class than the ECO 27 or the Rheem 13, the Takagi T-KJr2-IN-NG is not one of the most powerful, and may struggle to supply very large homes.


This is an excellent mid-sized gas-powered tankless water heater. However, if you have a small home or live in a warm climate (or both) you can probably spend less and get the same satisfaction. It is, however, very reliable and very efficient. This makes it a good choice even if you don’t need the extra power.

Rheem RTGH-95DVLN On Demand Natural Gas Water Heater

This is a very high output (9.5 GPM) gas-fired tankless water heater that is excellent for large households. It can easily supply, say, 2 showers, a dishwasher and a washing machine without any loss of performance.

It is a ‘condensing unit’ meaning that it reclaims much of the heat from its exhaust gasses to increase its efficiency.

Pros of the Rheem RTGH-95DVLN:

    • Massive output

At 9.5 GPM, there are few households that would demand more than this unit can give, in any climate.

    • Superior efficiency

As it is a condensing water heater, it can boast energy efficiency levels that allow it to recover its (admittedly) high purchase and installation price for houses that use a decent portion of its maximum output fairly quickly.

    • Size

Though it’s been called ‘a beast’, it doesn’t look like one. For its power output, it is very compact.

Cons of the Rheem RTGH-95DVLN:

    • Purchase price

This is the most expensive tankless water heater we are reviewing in this article. It will also be expensive to install, as it requires a gas supply and an external vent. It will make these costs back compared to a traditional water heater eventually, but ‘sticker shock’ might put it out of the reach of many homeowners.


Only a large home in a cold climate really needs something like the Rheem RTGH-95DVLN. If you need that kind of output and efficiency, though, it is well worth the price.

So, should I buy a tankless water heater?

Like every important question, the answer is ‘that depends’. If you don’t have $1000 or more, won’t be living in your home for more than a few years, or don’t particularly care about energy efficiency, a tankless water heater may not be for you.

Alternatively, if you are looking for a practical, space-saving hot water system that will more than pay for itself over its estimated 20 years of service, you may very well need one. Likely, these will become the norm rather than the exception over the next few decades.

If you need help determining if a tankless water heater is right for you, contact us to discuss your specific needs. We love to help, and we are always on call. 

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