Tankless Water Heater Reviews – Buying Guide 2023


Tankless Water Heaters: The Key to Efficient and Cost-Effective Hot Water Solutions. Our modern civilization relies heavily on hot running water in our homes, but traditional heaters can come with a hefty price tag and consume a significant amount of electricity. That’s where tankless water heaters come in, offering instant hot water with minimal energy consumption.

With so many options available on the market, choosing the right tankless water heater can be a daunting task. That’s why we’ve done the research for you and created a comprehensive buying guide and detailed product reviews to make your decision easier. Our team of experts has handpicked the best natural gas, propane, and electric tankless water heaters, ensuring that you get the best value for your money.

By switching to a tankless water heater, you’ll not only enjoy the convenience of instant hot water, but you’ll also reduce your monthly energy bill and help the environment by using energy more efficiently. Don’t settle for a traditional, outdated water heater. Make the smart choice and upgrade to a tankless water heater today!

We’ve put together some detailed reviews here on our website but here are 3 of our top recommendations if you’re looking for the best Natural Gas, Propane or Electric options.

Best Tankless Natural Gas Water Heater

If you want the highest efficiency then Rinnai RUC98iN Ultra Series is the way to go, this condensing natural gas unit is one of the very best. With an EF (Efficiency Factor) of 0.96 it’s just below the 0.97 required for an Energy Star rating but it’s still enough to allow for a rebate from the majority of local authorities. It’s super quiet and delivers hot water very quickly. The installation may be a little tricky but once it’s in you’ll be saving plenty on your energy bill.

Best Tankless Propane Water Heater

Compact tankless units are great for smaller homes or apartments. Takagi T-KJr2-IN-LP doesn’t take up a lot of space but it is still capable of supplying up to 6 gallons of hot water (up to 120 degrees) per minute. Its great energy efficiency has earned it an Energy Star rating so you’ll be shaving dollars off your energy bill once you’ve replaced your tank storage unit with this one. Gas water heaters are notorious for inconsistent temperature control when the water flow varies but not this one. They’ve used some clever gadgetry to ensure a consistent temperature regardless of flow rate.

Best Tankless Electric Water Heater

EcoSmart ECO 27 with Patented Self Modulating Technology is a 27W unit that has a small footprint, looks great and heats water really quickly. If you live in an area that experiences low temperatures and you require a high flow rate then this water heater is ideal. Even if your incoming water is a chilly 37 degrees this unit will still deliver 3 gallons of hot water per minute. When the incoming water is warmer then it can deliver as much as 6 gallons per minute which is sufficient to allow for two simultaneous showers. We really like the digital temperature display and control panel that allows for 1 degree increments in the temperature setting.

Installation Services

Tankless heaters are more complicated, and expensive, to install but once they’re in the energy savings make it worth the effort. While you might be perfectly comfortable with a DIY installation, check to see if your warrantee requires that the installation be done by a professional contractor. It’s always best to hire someone based on a recommendation. Amazon not only supply water heaters but they can also connect you with top notch installers. Simply enter your zip code and they’ll give you the option of hiring the contractor straight from Amazon. You can choose between a new installation, replacement only or replacement and haul away where they get rid of your old tank. You can check out the reviews of others to see if they had a good experience using the contractor.

Click here to see if there’s an installer in your area.


Why should I go tankless?


confused about going tanklessRegular cylinder, or tank storage type water heaters can provide a good supply of hot water but it comes at a cost. While many people only consider the purchase price when looking at different water heater options, it’s really the operating cost that you should be looking at. Regular models are designed to maintain the water temperature at the desired heat setting regardless of whether or not you actually need hot water at that particular time. This is what is known as “standby losses” and it results in a very inefficient use of energy and adds a lot of unnecessary cost to your utility bill. Tankless units only heat the water when you need it. This is why they are also called “demand type” water heaters. This means that you’re only using energy when you absolutely have to. The initial cost of purchasing a tankless water heater may be higher than a storage tank type but they are far cheaper to run. Depending on how much hot water your household uses and where you install your water heater, you could save between 27% and 50% on your energy costs.


Regular hot water tanks have a finite capacity of water that they can hold. As that hot water runs out through the faucet it is replaced by cold water. It take a long time to heat that water again. As a result you end up having to plan who gets to have a shower and when to wash the dishes so that there’s enough hot water to go around. If you go for a tankless solution then you won’t have any of these issues. The water that passes through the water heater is heated instantaneously and will provide you with endless hot water. As long as water keeps flowing through it you will keep getting hot water. No more cold showers!

How Does A Tankless Hot Water Heater Work?

These water heaters have no storage capacity and instead heat water as it flows through the heating coils inside the unit. This allows them to provide a constant stream of hot water that will keep coming as long as the faucet is open and the water heater is on. Tankless heaters are powered either by electricity or by gas (natural or Propane). The flow rate of the water that the water heater can provide is normally less than a regular tank heater but it is constant.

Pros And Cons Of Going Tankless

Con – Expensive upfront purchase cost

When you compare the cost of a tankless water heater with a tank storage heater they are clearly a lot more expensive to buy. If you’re looking at a condensing unit then the price tag gets pretty ugly.

Pro – Efficient energy use

Whether your aim is to reduce your energy costs or your footprint on the environment, the tankless heaters are your best bet. They use less energy than regular tank storage heaters and the savings on your running costs justify the higher upfront cost.

Con – Expensive installation

On most of the older tankless units the inlet and outlet water lines were on the bottom which made them difficult to use as a drop-in replacement for a tank water heater that has these pipes at the top. To reduce the cost, and effort, of the installation, look for a unit that has these pipes at the top of the unit. Some of the gas powered units require non-standard size gas lines. This means that you’ll need to install additional gas lines and interface them with your existing lines. You can avoid this by buying a tankless heater that uses standard ½ inch gas lines.

Pro – Compact size

The compact nature of tankless units makes them far easier to fit into a small space. The really compact units can be hidden away nicely in a cupboard which makes them great for smaller homes. It also means they can be installed closer to the faucets thereby reducing the amount of piping needed.

Con – Expensive servicing costs

Tankless water heaters will need to be serviced and descaled from time to time. Some lend themselves to a DIY service but others may need a contractor.

Pro – Long lifespan

While they may need some servicing, the tankless units will outlast tank storage type heaters by a long way. You should get between 15 and 20 years use before needing to replace it.

Con – Inconsistent water temperature

Because the tankless unit doesn’t store hot water it tries to regulate the temperature of the water as it flows through the coils. If the incoming water temperature varies then this gets a little tricky. With some of the older (and even some of the newer) units you could experience the water temperature varying by as much as 5 degrees. Also, in certain cases you could end up with what is called the “cold water sandwich”. This is when there is some warm water in the pipe, some cold water behind it and then the hot water coming out of the water heater. It’s not a great experience to get that bit of cold water while showering. Some of the top rated tankless products use a recirculation pump or a small buffer tank to get around these issues and provide consistent water temperature.

Pro – Endless hot water

While tanks eventually run out of hot water, the tankless heaters will keep supplying hot water for as long as you run them.

How To Choose The Best On Demand Hot Water Heater For Your Home

Size (Capacity)

When you’re choosing a regular tank storage water heater you’re concerned about how much water it can hold and how quickly it can heat a full tank of cold water. Because a tankless unit doesn’t store any water these comparisons become a little more complicated. What we’re really concerned with when choosing a tankless unit is how much water it can push out at once (flow rate) and how much it can increase the temperature of the incoming water by. For a medium size home you should be looking for something that can supply around 6 gallons per minute. If the flow rate is too low then you may need to decide between having a shower and washing the dishes. Doing both won’t be possible with a low flow rate. If the incoming water temperature is really low during winter then being able to heat it by only a couple of degrees just isn’t going to give you the hot water you’re after.

Fuel Type (Energy Source)

Your three options for energy source are natural gas, Propane and electric. Natural gas is your cheapest option but, like the propane unit, it comes with its own complicated installation issues. Electric units are very convenient, easier to install and completely quiet but they aren’t as efficient as the gas units. Check with your local authorities to see what rebates are available for the different energy sources before making your choice.

Energy Efficiency And Money Savings

outdoor tankless water heaterHow much energy can I save? If you’re just looking at energy savings then, in general, tankless heaters are more efficient that tank storage heaters. The biggest contributor to lost heat (tank or tankless) is the length of pipe between the water heater and the faucet. Using electric tankless water heaters makes it possible for you to install it closer to the faucet and get rid of all that piping. Gas units, even while they’re not heating water, will have a pilot light that is always on. This means that even though it isn’t heating water it still uses a little bit of gas to keep that pilot light going. The amount it uses varies from manufacturer to manufacturer and it’s a good idea to ask about this when making your comparisons. Some gas units will use an electric igniter and this removes the need for the pilot light. Electric tankless water heaters will give you your best energy savings. The electronic controls are always powered but this uses very little electricity.

If energy efficiency isn’t your only concern but you also want to know how much money you can save, then that’s a very different question. The short answer is: It depends. Your upfront purchase cost is going to be considerably more so as far as saving money is concerned tankless units are way behind tank units out of the box. You need to add the extra cost of installation because this is also going to cost more. After spending all of this money it now comes down to how long the water heater will last and what you pay for your energy consumption. Now it depends on what your local authorities charge for energy usage. If your utility costs are high per unit then the efficiency of the tankless units will pay for themselves far quicker. As an example: If you spend an extra $2000 upfront for a tankless unit and it saves you $200 off your energy bill then after 10 years you’ll make that money back. If the water heater lasts 15 or 20 years then it’s going to save you a decent amount of money. Of course you may need to factor in finance costs and escalating energy costs but this gives you a fair idea. If you get a tankless unit with a good Energy Factor (EF) rating then you can probably bank on a payback period of about 15 years for a whole house unit. It really depends on your energy source and the amount of water your family uses. Bank on saving around 37% on your energy usage and use this figure to work out roughly how much you would save in a year. It’s good to remember that savings in energy use are more important than just the dollars saved.

Costs Associated With A Tankless Solution

  • Purchase Cost

Don’t be surprised at the higher price tag on tankless units. They are considerably more expensive than tank storage units. Think double, or even more, if you’re looking for a good product. If you’re looking for a very efficient water heater then you’ll be looking at the condensing tankless water heaters and these get really pricey.

  • Installation Cost

For a new construction the installation cost of the tankless unit isn’t going to be a whole lot more than if you installed a tank storage unit. If you’re doing a retrofit then it can get significantly more expensive depending on how many changes you need to make to have the water pipes and gas pipes work with the new unit.
Click here to see the cost of installation in your area.

  • Maintenance Costs

The big enemy of tankless products is scale build-up. The extent of this problem really depends on the hardness of the water in your home. If you have very hard water then you may even need to consider installing a water softener. Either way, at some point your water heater is going to need to be descaled. On some units this is a pain and fairly complicated and time-consuming. On others it’s pretty easy and quick. Check what is required before making your purchase.

  • Running Costs

Like with any water heater, it’s going to need an energy source to heat that water. Fortunately, because the tankless solutions are so much more efficient, you’ll be using a lot less energy. Natural gas is the cheapest energy source option but you won’t see as big a difference in your energy bill when comparing it to a natural gas tank storage heater. Electric tankless water heaters use quite a lot of electricity to heat the water but then it’s only for a short time, with hardly any standby losses. If you’re comparing the running costs using propane then you’ll see a significant difference between the running costs of the tankless units and the tank storage ones.

  • Replacement Costs

If your water heater is regularly serviced then it’s going to outlast a tank storage unit by a long way. Bear this in mind when considering the replacement costs. A tank storage water heater may need to be replaced after 10 to 15 years but a good tankless heater could last you more than 20 years. Of course, when that day comes, it’s going to cost you a higher upfront cost again. Hopefully by that time we’ve found smarter ways to heat water.

Buy from a reputable dealer with a track record. Some dealers come onto the scene, sell a bunch of water heaters, and then go out of business. All those folks who thought they were getting a great deal now have nowhere to turn once they need to take advantage of the warranty or if they need some spares.

Is The Hot Water Really Instantaneous?

When we talk about “instantaneous” hot water we really refer to how long it takes for hot water to come out of the faucet. Storage tank heaters contain heated water and if you had a faucet come straight out of the tank you would certainly have instantaneous hot water. The problem is that the size of the tank normally means that it’s situated some distance from the bathroom or kitchen and the water needs to travel through several feet of pipe before getting to the faucet. This is why the first bit of water that comes out of the faucet is cold. Electric tankless water heaters don’t really provide hot water any faster than a tank water heater can but their advantage is in their size and where they can be installed. The smaller footprint of these water heaters and their energy source mean that they can be installed really close to the faucet. This results in a far shorter wait for hot water to come out of the faucet. If your heater is installed far away from the faucet then you won’t be getting hot water any faster than you would from a regular tank storage heater. Gas tankless water heaters will normally be installed in a basement so you’ll still be waiting a little while for that hot water to come through.

Warranty And Service Intervals

Tankless water heaters need to be serviced from time to time. The manufacturer of the water heater that you buy will indicate what these service intervals are. Serving the water heater will prolong its lifespan but can get expensive so it’s a good idea to know upfront what these costs are going to be. Skipping a service could be expensive too as many manufacturers will void the warranty if you do so. Make sure you check the fine print when making your purchase.


A lot of people balk at the high purchase cost of tankless water heaters but the lower running costs and constant supply of hot water justify this cost over time. There has been a lot of discussion around the true savings that the tankless options provide and there are valid arguments on both sides of the issue. As efficiencies and design improvements progress the tankless products make more and more financial sense. The units we reviewed above and elsewhere on this website would all make excellent choices to ensure your home has hot water without the high energy costs.