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Save energy and get hot water on demand with these top picks drinking water storage tanks
If you’re looking for ways to make your home more energy-efficient, tankless water heaters can help. Melanie Powers, president of Goodberlet Home Services, says, “They only heat water as needed, so you are not paying to keep water hot in a storage tank,” ultimately conserving energy.
Tankless water heaters come in both natural and propane gas or electric models. They’re also generally more durable than regular water heaters, with many lasting 20 years or more, tend to be smaller, and can be wall-mounted so you can have more space.
We researched and evaluated the best tankless water heaters to help you decide if this is the right type of water heater for your home.
To evaluate the best tankless water heaters, we looked at type (gas-powered or electric), size, flow rate, total Btu, and watts.
It has a steady temperature output, so it won’t suddenly scald you.
You’ll likely need an electrician to install it (or to consult with one before buying) since it needs a 300-amp electric service, which is not compatible with all houses.
As one of the most energy-saving tankless water heaters on our list, the Stiebel Eltron Tempra 36 Plus won’t ever use more electricity than you need it to, and since it has a minimum heating setting of 68°F, it won’t allow the water to surprisingly scald you when you’re quickly washing your hands.
The unit is only 14.5 inches tall, and very quiet, with a flow rate of up to 7.5 GPM and 36,000 watts. It has a clever technology that slightly reduces the water flow when hot water is in high usage so that you won’t be shocked by the cold-water sandwich while it’s trying to keep up with the hot water demand.
The temperature can be set with the intuitive buttons and control knob, and there’s also a temperature memory setting. Its automatic modulation helps save you even more energy, and the digital display will always let you know the temperature.
An advanced flow control maintains a consistent temperature output, and there’s no venting required to install. This is another indoor unit that has a simple, minimal design, and though it’s compact enough to be hidden away, it won’t be unsightly if visible.
You’ll want to call in an electrician to install this unit as it requires 300 amps, which may require an upgrade to your electrical service panel. It comes with a seven-year warranty in the event of any leaks and a three-year warranty on parts.
Product Details: Type: Electric, indoor | Dimensions: 14.5 x 4.63 x 16.63 inches | Flow Rate: Up to 7.5 GPM | Total Btu: Not listed | Watts: 36,000
When replacing your hot water heater, the main decision you’ll need to make is between a tankless model or one with a tank. Both have pros and cons, so which one you choose will come down to your household’s size and lifestyle.
Tankless heaters offer hot water on demand, so you don’t have to wait for the water to heat up whenever you want to take a hot shower or wash dishes. They conserve more energy compared to tank water heaters.
Nathan Hudelson, master plumber and owner of Schlueter Plumbing says, “A single tankless can usually supply three normal showers at the same time.” He also mentions that they come in handy for small pool-size garden tubs.
They also tend to be compact and wall-mounted, making them suitable to install in apartments and small spaces. Hudelson says they are good for businesses that need continuous hot water for dishwashing. On the negative side, the smaller size means that larger households may need more than one unit.
Tank water heaters can be cheaper in large households with high water usage. The downside is the bulk—you’ll need space to install it in a basement or laundry room. And they have a shorter lifespan—expect it to last around 10 years on average, compared to a tankless unit that can last 15 years or more.
It’s an excellent option for families and large homes with multiple bathrooms because of a high flow rate.
The WiFi features require purchase of a separate module.
Condensing gas heaters, like this Rinnai option, are more energy-efficient and have a higher flow rate than electric models—making them a great choice for family use and large households with several bathrooms. It runs up to six fixtures at once, with a flow rate of up to 9 GPM.
The heater is Energy Star qualified, meaning it results in fewer emissions in addition to saving more energy. One of its best features is smart technology that tracks water usage and employs that data to provide unlimited hot water on demand at peak efficiency.
This feature also helps to save energy and reduce your utility bill during times when you don’t need to use as much hot water. The model works with Wi-Fi, so you can control it remotely with your phone or voice commands, but to access these features, you need to purchase a separate module.
Product Details: Type: Natural gas, indoor and outdoor | Dimensions: 9 x 9 inches | Flow Rate: Up to 9 GPM | Total Btu: 160,000 | Watts: Not listed
These terms refer to how gas models heat water. Condensing tankless water heaters are larger and save more energy because they trap exhaust heat by condensation and then re-use it to heat water. One downside is that condensing units tend to leak if the drain is not maintained properly.
A non-condensing heater only heats the water directly with the primary heat exchanger. They are cheaper upfront, and more compact. But they tend to burn more energy, and they require venting, so installation can be pricier up front.
It has four modes that automatically keep the water to a consistent temperature for different purposes.
It’s not portable like many propane options.
If you don’t have easy access to natural gas, we recommend using a propane model that’s specially designed for indoor use. The Ranein provides hot water on demand for two or three fixtures, with a steady 3.6 GPM flow rate, a sleek exterior, and a compact design.
Unlike many propane picks, the Ranein heater is not portable, meaning you can’t take it with you on camping trips or van life adventures, but it is a strong choice for a smaller home. It has four modes that keep a consistent temperature suited to a variety of purposes, such as dishwashing.
As a non-condensing heater, installation is slightly more complex and you’ll likely need professional help. But a vent pipe is included in the set, meaning you won’t need to run out and buy one.
Product Details: Type: Propane, indoor | Dimensions: 19.09 x 7.67 inches | Flow Rate: 3.6 GPM | Total Btu: 80,000 | Watts: Not Listed
There are three types of tankless water heater—electric, natural gas, and propane gas. We chose one top pick from each category—the Stiebel Eltron Tempra 36 Plus is our best electric option, the Rinnai RXP160iN Tankless Water Heater is our top natural gas pick, and the Ranein Tankless Water Heater is the best propane.
Tankless water heaters can be condensing or non-condensing, gas or electric, indoor or outdoor (sometimes both). They are all designed to be more energy efficient than standard water tanks to varying degrees.
Gas models are typically more expensive and complicated to install because they often require venting and gas lines. Electric units, on the other hand, are generally smaller and cheaper to install. According to Powers, they do tend to have lower flow rates than gas units.
According to Hudelson, electric models consume a lot of power, which could spike your energy bill. On the other hand, gas units heat up more quickly and have more power. “They can keep up with greater demands of hot water,” Powers says.
Hudelson advises shoppers to stick to name brands when buying tankless units. “Getting an off-brand tankless could mean waiting weeks for parts—if they are even available,” he says. “Brand names associated with tank-type water heaters aren't always the best for tankless.”
The correct flow rate depends mainly on the size of your home. “The average flow rate of 3.2 GPM (gallons of water per minute) is good for smaller areas, while around 5 to 7 GPM is good for bigger spaces,” Powers says.
For those who want the hot water to flow out quicker, she recommends buying a circulation pump to increase the flow rate. Hudelson says that shoppers shouldn’t look exclusively at flow rates to get the whole picture. “The Btu input and efficiency will tell a truer story of what that heater will deliver,” he says.
Water heater issues are mainly caused by incorrect installation, says Hudelson, which is why hiring a professional is preferable over DIYing. Installation costs range according to the market and also the conditions inside your home. Hudelson says that costs in his area typically start around $5,500.
Gas tankless water heaters use a Btu (British thermal unit) rating to measure the amount of heat energy a unit produces. The typical Btu range for gas is about 140,000 to 200,000.
Electric units measure heating capacity in watts. The wattage for most residential tankless heaters ranges anywhere from 1,000 to 36,000 watts, depending on the size. Hudelson says it’s more important to evaluate Btu and efficiency specs rather than flow rates, as the numbers can be misleading or misinterpreted.
There are several cons of tankless water heaters. They’re typically more expensive to install—plan to spend at least $1,000 for professional installation. You can expect lower flow rates on average, so they’re better suited to smaller homes. Also, these units require more frequent maintenance due to buildup.
Another issue that comes up when using tankless water heaters is “a cold-water sandwich,” says Hudelson. “This is when the water takes a few seconds (or minutes) to warm up again, leaving a sandwich of cold water in the line for the next unsuspecting victim in the shower,” he explains.
Tankless water heaters are durable and can last up to 15 or 20 years with regular maintenance. This makes the up-front investment worth it, as you won’t need to worry about replacing it after a few years.
Tankless water heaters are more expensive to install compared to the average water heater, and the units themselves can be pricier, but you’ll likely save money on energy costs down the line. According to Powers, expect to pay anywhere from $1,000 to $5,000 for professional installation.
Hudelson says to look at gallons per minute to determine capacity (for example, the Rinnai RXP160iN Tankless Water Heater has a flow rate of up to 9 GPM, or about six fixtures). A small unit with a flow rate of 2 to 5 GPM can cover a home with one or two bathrooms. For more bathrooms, look for a flow rates of at least 5 GPM.
Temperature also plays a role when assessing how many tankless water heaters you need. “A tankless that produces 9 GPM in the Southern states may only produce 6.5 GPM in the northern climates because the water is colder going into the heater,” Hudelson says.
This article was written by Kat de Naoum, who has more than 10 years of writing experience and updated by Nor'Adila Hepburn, a writer who specializes in writing in-depth buying guides for Better Homes & Gardens.
water tank for house To find the best tankless water heaters they researched and evaluated a range of gas and electric water heaters from multiple brands. Nor’Adila also spoke to experts Melanie Powers, president of Goodberlet Home Services, and Nathan Hudelson, master plumber and owner of Schlueter Plumbing.