Hot water shouldn’t be just a luxury. We use it in everyday life, for cleaning our homes and ourselves. But sometimes, a traditional water heater doesn’t have the capability of giving you what you need.
Tankless water heaters supply endless hot water anywhere in the house, on demand, and that is great to meet the demands of your family as well as to add a little luxury to your life.
What Is a Tankless Water Heater?
Unlike conventional water heaters, tankless water heaters do not require storage tanks. Rather than that, they generate hot water on demand. When you switch on a typical water heater, the shower draws water from the tank, which has already been heated.
In households that have a tankless water heater, the shower will draw water through it, and the water will flow directly from the source, rapidly heating as it passes through the pipes and through the heating components on its way to your shower.
Why Use a Tankless Water Heater?
With a tankless water heater, you don’t have to worry about overtaxing your traditional water heater and running out of hot water at the worst possible time. You can relax in the shower and do all of your laundry and dishes without concern, as well as almost no wait time for the water to heat.
Even more importantly, the investment you put into tankless water heaters will save you money in the long run because you won’t have gas and electric running to maintain the water temperature constantly. And because most tankless water heaters are localized, they don’t take up much space at all. So, how do you choose a tankless water heater?
Tankless Water Heaters vs. on Demand
Tankless water heaters are also known as “on demand” heaters, with some people referring to them as “instantaneous water heaters” as well. The name derives from the fact that these units will offer hot water when you turn on a faucet instead of pre-heating water and storing it inside the tank.
Compared to other units, on demand heaters will not cause standby energy losses because they don’t need to constantly store and keep water at a certain temperature, leading to money savings in the long run.
Tankless Water Heater vs. Boiler
A boiler serves as both a source of heat and hot water for your home. On a household level, this implies that when you have a boiler, every appliance and faucet inside the house that needs hot water will draw it from the same source.
However, if you have a water heater, it will only provide you with hot water, meaning you need another source to cover your heating needs. That makes a boiler more versatile compared to a tankless water heater.
Hybrid Water Heater vs. Gas
Water heating accounts for between 14 and 18 percent of your utility expenditures, according to the US Department of Energy. Thus, it makes sense to buy a water heater which is energy efficient.
Gas water heaters (especially tankless models) typically consume less energy compared to electric water models, which means they are more energy efficient and frequently Energy Star certified, which results in additional savings.
This might leave you inclined to opt for a gas water heater, but an alternative would be a hybrid heater because they can be two to three times more efficient compared to electric or gas units.
In essence, hybrid systems are heat pump water heaters because they heat water using two different processes. A heat pump works by extracting heat from the air and utilizing it. The primary benefit is energy savings. However, if the need for hot water increases, the hybrid heater can convert to electricity and function concurrently.
What Size Tankless Water Heater Do I Need?
The greatest temperature rise that a tankless water heater can achieve at a given flow rate is rated. Thus, in order to properly size a demand water heater, you must first estimate the flow rate and temperature increase required for its intended application in your home. It is critical to remember that you should never attempt to save money by purchasing an undersized tankless water heater.
Based on the number of devices that you wish to operate and the total flow rate of those devices. Then, add their flow rates together (gallons per minute). This value represents the required flow rate for the demand water heater. You also have to calculate the required temperature increase. Take the desired output temperature and subtract the incoming water temperature.
Gas tankless water heaters can achieve a greater temperature rise per gallon of water than electric versions. The majority of demand water heaters are designed to operate at a range of inlet temperatures.
In most cases, a 70° F increase in water temperature is attainable at a flow rate of 5 gallons per minute for gas-fired demand units and 2 gallons per minute for electric demand water heaters. Increased flow rates or decreased inlet temperatures can occasionally reduce the temperature of the water at the farthest faucet.
Is It Worth Switching to a Tankless Water Heater?
Tankless water heaters operate in a somewhat different manner than conventional water heaters. Rather than storing gallons of hot water, this particular type of heater heats water only when it is required. It appears to be a little box concealed within some pipework. When you turn on a hot water tap, the water is instantly heated.
The primary reason why people choose this type of heater is that they consume less energy because they heat water only when it is required. Each year, you can save hundreds of dollars on your energy bill. Due to the fact that they do not waste energy, you may also benefit from the sustainability and eco-friendliness of such a unit.
So, if you want a steady stream of hot water, a tankless water heater might be the right option for you.
Top 5 Best Tankless Water Heater Reviews
To help you better understand what the best tankless water heaters have to offer, we’ve compiled a list of our top picks with easy to digest details on each.
The Stiebel Eltron tankless water heater provides an endless flow of hot water on demand, allowing you to enjoy a hot shower as long as you’d like, as well as assuring you always have hot water when needed. It heats water to a range of 86-140 degrees, based on your settings, and there is only a few seconds’ wait for that heat immediately upon request.
The water heater has an easy to read digital temperature gauge, and it operates silently, so you don’t have to worry about excess noise under your sink or in your bathroom. In addition, its small size makes it easy to install anywhere, so you can add one to any source of water in your home for a complete solution.
This particular unit is also eco-friendly. There is no venting required, and it has automatic modulation capability, which saves you even more energy. The Stiebel Eltron tankless water heater has a 7-year warranty on leakage and a 3-year warranty parts, so you can rest assured it will offer you long lasting quality. Like many appliances, the water heater runs on 240 volts for great power output, while still remaining efficient.
- Small and lightweight for easy installation
- Operates on a broad temperature range
- Easy digital temperature readout
- Eco-friendly with automatic modulation
- Long warranty for peace of mind
- May require expert installation
- The price point is higher than the average
The Atmore ThermoPro Series tankless water heater ranks well in terms of cost, ease of use, and durability, not to mention overall performance. The digital temperature control is easy to use, much more so than the dials on old, traditional water heaters, and you can make changes in increments of a single degree for precision, with full range up to 135 degrees.
In addition, the interior of the water heater is made of stainless steel, so there is resistance to corrosion, which leads to greater efficiency in heating as well as a longer lasting product. And even with the savings through low power requirements and localized heating processes, you get instant piping hot water with little wait. The unit is rated to heat water as cold as 37 degrees flowing at nearly 2 gallons per minute to your desired temperature.
- Self-modulating system regulates water flow
- Programmable with 1-degree increments for precision
- Heats cold water faster than average
- Easy to use with digital readout
- Durable with stainless steel interior
- Still a bit costly
- May not be sufficient for cold climates
The Bosch Electric Mini-Water Heater is a little different than most of the ‘tankless’ devices used to instantly heat water. This is a local, 4-gallon water heater that can fit in convenient locations, including under the sink, so you have an immediate source of hot water on demand. It can be mounted to the wall, the floor, or a shelf, and it conveniently plugs into a standard outlet.
Because the tank is so small, it refills and heats quickly for continuous output. It also allows you to use one of these water heaters only where you really need it, so all the hot water from a larger heater can go toward the shower while you have instant local hot water at any sink or other area of the house.
The water heater is low maintenance and has glass lining for long lasting use. The durable materials mean that you won’t have to worry about replacement quickly. It’s also highly efficient, rated at 98% efficiency, so you don’t lose out on power.
- Easily, local installation
- Instant hot water at any location in the house
- Affordable price
- Ease of installation – plugs to 120VAC outlet
- Still requires a tank
- Need to find installation location
The Rinnai Tankless water heater is a great solution if you don’t have a local place to mount a tankless water heater. Perhaps you don’t have enough under-counter space and need a different solution, or you want to have instant hot water in the entire house. Rinnai has created a high efficiency tankless water heater that feeds off natural gas and is installed outdoors.
Depending on ground temperature, the Rinnai tankless heater can provide heat instantly for up to 5.3 gallons per minute flow, which is far better than the average tankless heater. In addition, you can control it with a mobile app, setting schedules, timers, and even vacation mode when you’re away so you don’t use unnecessary energy.
In addition, the Rinnai tankless water heater is backed by a significant set of warranties, including 10 years on the heat exchanger, 12 months for labor, and 5 years for parts. This makes it great for your peace of mind, so you have no hassle with any product issues.
- Easy to use no matter your situation
- High powered with gas
- Programmable and connects to an app for settings
- Backed by great warranties
- Requires natural gas hookup
- Outdoor unit – need outdoor space
Considering that it can handle a whole house (depending on how high your demand is and the size of the home), the EcoSmart electric tankless water heater is perhaps the best bargain around. The cost is similar to single location units, but it is capable of handling the entire house and saving you up to 50% of the cost of heating your water.
In addition, the size of your water heater means less storage space, regardless of its location. The EcoSmart tankless heater gives you great performance and instant hot water while also freeing up a great deal of space for more storage, whether in an attic, basement, or closet. There’s no need to hold a tank full of hot water, the unit heating the water as it passes through.
It also incorporates advanced self-modulating technology, so it never utilizes excess energy. You also get the expertise of the company in choosing the right model for your needs, sized based on location (for average ground temperature), as well as the capacity based on your usage.
- Small to increase storage space
- Instant hot water for the whole house at a similar cost to one location units
- Multiple sizes available for various applications
- Limited lifetime warranty
- May be difficult to install
- Capacity may not be enough for high demand
What Is the Downside of a Tankless Water Heater?
Sadly, a tankless water heater has more than one downside, so let’s quickly take a look at the most common disadvantages that tend to bother people when it comes to this particular type of water heater.
1. Takes long to deliver hot water
One of the major downsides of tankless water heaters is that they are capable of delivering hot water slower than conventional heaters. Remember that tankless water heaters do not keep hot water ready to use at all times.
2. Inconsistent water temperature
You’ve probably heard of a “cold water sandwich” while studying tankless water heaters. A cold-water sandwich occurs when using hot water intermittently, causing a combo of hot – cold – hot water which could make your showers feel unpleasant.
While you turn off and on the hot water quickly, like when hand-washing dishes, the pipes still have hot water in them. The small delay between water flow and heater activation generates a frigid burst before hot water.
Tankless water heaters also cannot keep up with many showers running at the same time. If your water heater isn’t big enough, you’ll find it difficult to run the dishwasher and have a shower at the same time. Flow rate is the essential factor to look at while looking for tankless water heaters.
3. No hot water during power surges
When a storm takes out power, you won’t get any hot water either. Even gas-powered ones require an electric control panel to work. In the event of a power outage, you will be without hot water regardless of your tankless water heater.
How to Flush a Tankless Water Heater
The manufacturers of tankless water heaters recommend flushing their systems at least once a year to prevent the development of different kinds of minerals (such as calcium) within the device — even more frequently if you have hard water. Certain units will notify when they require flushing.
To flush your tankless water heater, you’ll need:
- 5 gallons of white vinegar
- Adjustable wrench
- (2) 6-foot sections of garden hose
- Connectors for the garden hose
- Pond pump
- 5-gallon bucket
- Electrical tester (non-contact)
Step One: breaker panel
Locate the breaker panel and turn off electricity to the heater. For gas heaters, rotate the gas valve to interrupt the gas supply to the heater.
Step Two: remove plate
Take the screwdriver and remove the heater’s cover plate to uncover the wiring. Place the non-contact electrical tester’s tip against the terminal’s wires. If the tester’s light turns on, there is still power running to the heater, in which case you have to turn off the main circuit breaker to your home. Only continue with the next step when the tester’s light is off.
Step Three: cold water supply
Shut down the cold-water supply that’s connected to the heater and the hot water supply that transports water from the heater to your fixtures.
Step Four: attach hose
Attach one end of a garden hose to the pond pump outlet and the other end to the cold-water isolation valve.
Step Five: attach second hose
Attach the second garden hose to the hot water isolation valve. Use an adjustable wrench to tighten all the connectors.
Step Six: pump
The open end of the second hose and the pump should be placed in the bucket with the white vinegar, allowing the pump to run for about 45 minutes. When the time is up, turn off the pump and allow the vinegar to drain from the heater using the shoes in the bucket. Shut down the cold-water isolation valve.
Step Seven: flush
Throw away the vinegar and put the open-end hose back into the bucket. Turn on the cold-water supply valve and allow water flow for about five minutes.
Step Eight: wait 5 minutes
When the five minutes are up, close the cold-water supply valve and remove the pieces of garden hose from the inlet valves. Shut down the hot water isolation valve.
Step Nine: Check manual
Look at the owner’s manual to learn how to remove the inlet filter screen from your particular water heater model. Rinse it to remove sediments and put it back in place.
Step Ten: remove air
Turn on the hot and cold-water supply valves. Open a few hot-water faucets throughout the house to remove any trapped air in the hot-water lines. Once there is no more air in the lines, close the faucets.
Step Eleven: double check
Check all the connections to see if there are any leaks. If you have a gas water heater, make sure to turn the gas supply back on.
How Does a Tankless Water Heater Work?
If tankless units heat and store hot water inside the tank, tankless heaters lack this particular component. As soon as you turn on the water at the faucet, the cold-water pipe feeds water into the unit, which uses either electric or gas-burning elements to heat up the water.
This means that you don’t have to wait for the tank to fill, so these units will offer a constant stream of hot water. However, this limits the output rate of your hot water, which is typical at 2 to 5 gallons per minute.
If you opt for a gas-fired water heater, you will get a higher flow rate compared to what you get when choosing electric models. Even so, keep in mind that even the largest gas-fired units will not be able to offer a high flow rate if you have a large household that requires running multiple faucets/showers at the same time.
How Much Is a Tankless Water Heater?
Tankless water heater systems are not inexpensive: the typical cost of a tankless water heater, including installation, is around $3,000. The entire cost is determined by the model selected and the extent to which your home requires retrofitting.
Can You Run out of Hot Water with a Tankless Water Heater?
To answer this, we must first explain how a tankless system differs from a storage tank system. A storage tank system works by reserving hot water until it’s ready to use. So the hot water supply in the tank can run out and it takes a while for the electric heating elements or natural gas burners to refill it.
A tankless system doesn’t have a limited supply of hot water. Instead, the water heater heats water as needed. When you switch on the hot water shower, the tankless system detects water flow inside the lines and begins heating it via a heat exchanger. It will do this as long as there is demand, so you will never run out of hot water.
But you need to consider the following: even if a tankless system never runs out of hot water, it might be overloaded. You can run a single shower all you want and still get hot water, which makes the heater struggle with offering you a constant flow of hot water.
As a result, we advise working with experienced water heater installation before going tankless. Your water usage pattern may benefit from a storage tank. Or you could build multiple tankless systems.
Which Is More Efficient Tankless Water Heater or Heat Pump Water Heater?
Heat pump water heaters are, on average, significantly more efficient than tankless water heaters. However, they require quite a bit of room, generate quite an amount of noise, and do not provide rapid hot water. Tankless water heaters, on the other hand, consume significantly more energy but provide an instant, steady supply of hot water.
In naturally warmer climates, heat pump water heaters are more effective. The warmer the air, the more efficiently the heat pump can heat the water without the use of energy. While they can be effective in colder regions as well, they perform better in warmer climates.
How Much Does It Cost to Replace a Hot Water Heater with a Tankless?
On average, it costs between $800 and $3,500 to convert or replace a tank water heater with a tankless system. The cost of a tankless water heater is determined by the flow rate, the fuel sources, and the type of brand in question.
Installing a tankless water heater can cost between $700 and $4,600 for gas systems and between $600 and $2,500 for on-demand electric devices. While gas tankless water heaters cost more, they come with longer warranties and have an annual energy cost of $150 to $260 less than electric tankless water heaters. Annual operating costs for electric systems range from $300 and $540.
The Bottom Line
When it comes to having hot water, getting instant results and not wasting energy are high priority. With a tankless water heater that fits your lifestyle and your budget, you can easily accomplish both and feel satisfied that you’ve taken the right step in upgrading your home.