Best tankless water heaters for your home: How to choose the right one
Tankless water heaters are a great way to save on space and your utility bills. But which should you buy? We rounded up some of the best.
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A tankless water heater can be a great way to save on both space and your utility bills compared to a traditional water heater. They also require less upkeep and typically have a longer lifespan, allowing you to say goodbye to frequent water heater maintenance . However, with so many models available, which one should you choose? We've rounded up some of the best tankless water heaters based on budget, the size of your home and the use case.
How to choose the right tankless water heater for your home
The biggest factor in choosing a tankless water heater is the size of your home and how many people live in it. The larger your house is and the more people that live there, the more likely you are to use multiple fixtures requiring hot water. You want a tankless water heater with a flow rate that matches or exceeds the flow rate you need based on how many fixtures you think you'll use at once in your home.
According to This Old House , the average flow rates for common fixtures, which are measured in gallons per minute (GPM), are as follows:
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Dishwasher — 1 to 2.5 GPM
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Kitchen or bath faucet — 1.5 to 2.2 GPM
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Showerhead — 1.25 to 2.5 GPM
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Tub filler faucet — 4 GPM
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Washing machine — 1.5 to 3 GPM
Once you find the flow rate of your fixtures, you can add them together to come up with the maximum flow rate you may need from a tankless water heater. However, that's not all: you also need to account for the temperature of the water that enters your water heater. Simply put, the colder the inlet water, the more your tankless water heater has to work to get it up to your set temperature, which will lower its flow rate. If you live in a colder climate, your inlet water will be colder and vice versa.
If that sounds complicated, it can be. Fortunately, each of our tankless water heater picks has a size guide on its product page that can give you an idea of how it will perform in your region. For those in cooler climates, consider whether you may need to step up to a model with a higher flow rate to account for colder inlet water.
Best tankless water heaters for your home
Rinnai is one of the best names in tankless water heaters, and its latest line of indoor-outdoor tankless water heaters are a good overall choice for most homes. This particular model runs on either natural gas or propane without the need for a conversion kit, giving you some extra flexibility (unless you need an electric heater). It can also be mounted either indoors or outside, though you need a conversion kit if you want it outdoors.
Able to output 130,000 BTUs, this water heater can put out up to 7.1 gallons per minute (GPM), which is enough to handle around four fixtures running at one time. Given showerheads can put out around 2.5 GPM (under 2 GPM for WaterSense showerheads), that gives you quite a bit of headroom even if you have multiple people taking showers at the same time. If you need more, there are higher output models available.
It's also very energy-efficient and comes with a quick flush system that makes it easy to do routine maintenance. You can add Wi-Fi connectivity to keep an eye on how the heater is operating with an additional module sold separately.
Pricing is on the higher side, so this isn't a great option if you need a budget heater or have a very small home with one or two people and don't require much output. However, it's fantastic for most homes that may be running more than a couple of faucets at once. As one verified Amazon reviewer put it, " There is nothing to dislike about this water heater. I absolutely love it. The water gets hot almost immediately. "
- Can run on gas and propane without conversion kit
- Up to 7.1 GPM
- Optional Wi-Fi module
- Super efficient
- No electric option
- Requires conversion kit for outdoor mounting
Another big name in the tankless water heater game, Rheem makes some great models and this one is no exception. This IKONIC series model runs on natural gas and it's perfect for large homes with a lot of water fixtures and household members. There is a propane model available as well , but you can't get both in one unit.
The biggest benefit of this IKONIC model is that it can output up to 11.2 GPM, which is enough to power up to four showers at once. It also has Wi-Fi smart technology built in, giving you access to controls on your phone to change settings and track energy and water usage.
While this isn't a tiny water heater by any means, it is a bit smaller than some others on the market with similar output. It's also very energy efficient if you want to cut your utility bills down a bit. If you live in a warmer climate, there's an optional outdoor conversion kit that allows you to mount this model outside.
This is definitely overkill if you have a relatively small or moderate sized home, but larger families will love the output efficiency. It's also very expensive, so be sure to evaluate what your needs really are before buying.
- Natural gas or propane
- Built-in smart features
- Super efficient
- Optional outdoor mount
- No electric option
- Propane and natural gas are separate models
- More expensive than others in our guide
While it isn't the most robust option on this list, the Stiebel Eltron Tempra 24 Plus is a good value for those who want to save some money while still getting decent output. This is an electric model, so you don't have the capability of using gas or propane as a fuel source. However, it can reach up to 5 GPM in warmer climates, giving you enough got water to run two showers and a sink at once.
If you live in a more moderate climate with cooler groundwater, it's more likely you'll see somewhere between 3.1 and 4 GPM. That's still enough to feed a couple of fixtures with hot water at the same time. Unfortunately, large homes will find this unit lacking, only making it suitable for those with a couple of people who may need hot water simultaneously.
That said, it's an efficient unit that doesn't require any venting. It's also quiet and compact, making it easy to tuck away without taking up too much space. For the money, this is a good pick if you don't need much from your tankless water heater.
- Electric
- Compact and quiet
- Up to 5 GPM in warm climates
- Efficient
- No gas or propane option
- Not great output for more than two fixtures at once
If you live in a small home with only one or two bedrooms, you don't need a ton of waterflow. That means you can go with an efficient model that costs a lot less than others on the market. That's exactly where this EcoSmart tankless water heater falls on the spectrum.
This is an electric heater, so you can't use propane or natural gas with it. However, that allows it to be pretty compact at only 17 x 14 x 3.75 inches. Not only does this save you space in a small home, but it allows you to also use it as a point-of-use heater for a single fixture like a sink or shower.
This model can hit up to 4.3 GPM but only in very warm climates. Expect output to be closer to 2.5 GPM is you live in a moderate climate or around 1.8 GPM with very cold inlet water. That should be enough to run a shower in most climates, though it might struggle more in northern areas with colder inlet water.
The biggest benefit with this EcoSmart model is that it's very cheap compared to larger alternatives. If you live by yourself and only run one or two fixtures at once in a small home, this is a solid pick.
- Electric
- Very efficient
- Can also be used as a point-of-use heater
- Up to 4.3 GPM
- May not be sufficient for running more than two fixtures at once
- No gas or propane option
If you just need a compact water heater for one fixture, this Rheem model is worth a look. Intended as a point-of-use heater, you can install this model right by the fixture that needs it to provide unlimited hot water on tap. The best application is under a sink, but those in warm climates might be able to get away with using it for a single shower.
The Rheem RTEX-08 is rated to provide up to 1.95 GPM of hot water, but that's only in warm climates where your inlet water temperature is between 62 and 77 degrees Fahrenheit, or enough for a shower. For cold climates with inlet temperatures between 37 and 47 degrees Fahrenheit, you're looking at an output of 0.94 GPM, which is just enough to power a single sink. If you're somewhere in between, expect your hot water flow to fall somewhere in between.
This unit is very small, coming in right around 13 x 8 x 4. That makes it easy to hide away out of sight near the fixture you want to use it with. A simple dial controls whether it's on or off and adjusts temperature on a digital display. One Amazon reviewer called it a great product for small areas, stating, "My husband installed this in his separate garage. Works great for cleaning up tools and hands. So much better than always having cold water in the garage."
- Electric
- Very compact
- Good for point-of-use heating
- Efficient
- No gas or propane option
- Only good for one fixture at a time
- May not do well in colder climates
Should you install a tankless water heater yourself or hire a plumber?
A person turns down the temperature on their tankless water heater
In most cases, you should hire a plumber to install your tankless water heater. Depending on the model you get, you may need to adjust your home's plumbing, especially if you're coming from a traditional water heater with a tank. This can be easy to get wrong if you aren't experienced in working with residential plumbing, potentially resulting in costly mistakes. Additionally, some tankless water heaters may require you to have them installed by a professional to take advantage of the warranty. Read the warranty terms carefully to ensure you don't accidentally void it.
That means you'll end up paying more than installing the water heater yourself, but it's worth making sure it's done right. Installing a tankless water heater is one of several great ways to boost your home-energy efficiency and could make up for the cost of installation over the long haul. If you're still mulling it over, read our full guide to choosing the best water heater for more tips.
