Tankless water heaters are popular among homeowners looking for a cost-effective and efficient way to heat their home’s water. Tankless water heaters provide an endless supply of hot water without the need to store and heat a large water tank.
In this article, I’ll help you understand the key features to look for in a tankless water heater and compare the top models on the market. From energy efficiency to family size, I’ll help you make an informed decision when it comes to choosing the best tankless water heater for your home.
Tankless water heaters offer a variety of benefits, including:
- Endless Hot Water – You can heat water on demand, which means you’ll never run out of hot water. This is great for large households.
- Lower Energy Bills – Tankless water heaters are incredibly energy-efficient. They use up to 50% less energy than traditional tank-style water heaters, which means lower energy bills for you.
- Longer Lifespan – Tankless water heaters can last up to 20 years, which is nearly double the lifespan of traditional tank-style water heaters.
- Smaller Footprint – They are much smaller than traditional tank-style water heaters. This means they can fit in tight spaces and don’t take up as much room in your home.
- Safe & Reliable – Tankless water heaters are much safer than traditional water heaters, as they don’t store hot water and therefore don’t present the risk of scalding. They are also equipped with advanced safety features, such as built-in temperature sensors, that help keep your family safe.
- Eco-Friendly – They don’t require large amounts of energy to heat water and can help you reduce your carbon footprint.
This is a question homeowners face when considering a tankless water heater installation, and the answer is not always straightforward. The size of the water heater you need will depend on a few factors, including the size of your home, the number of bathrooms, and the number of people living in your home.
Generally, for a single bathroom, a small tankless water heater like a 5-gallon unit will be sufficient. However, if you have more than one, you’ll need an 8-9 GPM for two bathrooms, and for 3 or more bathrooms a 10-11 gallon tankless water heater might be necessary.
From size and fuel type to energy efficiency and safety, here are some of the key factors you should consider when selecting a tankless water heater.
Tankless water heaters come in a variety of sizes, from small models that are suitable for single-person homes to larger models that can accommodate multiple people. Choosing the right size heater for your home is important, as it will determine how much hot water you can get at one time. If you have a family of 4-5 people, a 10-11 GPM tankless water heater may be the best option.
Tankless water heaters come in two main types: electric and gas. Electric models are more energy-efficient than gas models, but they can be more expensive to install and maintain. Gas models are cheaper upfront, but they can be less efficient and more expensive to operate. Depending on your home’s fuel type and availability, you’ll need to decide which type is best for you.
One of the main benefits of tankless water heaters is their energy efficiency. Many models are rated to be up to 40 percent more efficient than traditional storage tank water heaters. When shopping for a tankless water heater, you should look for models with an Energy Star rating, which indicates that it meets or exceeds the federal government’s energy efficiency standards.
Tankless water heaters require professional installation, and the cost of installation can vary depending on the model you choose. Generally, installation is more expensive with tankless models than with traditional water tanks. Make sure to factor in installation costs when deciding which tankless model is right for you.
The cost of a tankless water heater will vary depending on the size and model you choose. Tankless models are more expensive than traditional water tanks. However, depending on your needs and the amount of hot water you use, the cost of a tankless water heater can be worth it if you’re looking for long-term savings.
Safety is another important factor to consider when selecting a tankless water heater. The model should be certified by a recognized safety laboratory, such as Underwriters Laboratories (UL). This will ensure that it meets the highest safety standards. Additionally, it’s important to check the manufacturer’s instructions for use and maintenance to ensure that it is properly installed and operated correctly.
#1. Best Overall: Rinnai RU199iN Condensing Tankless Water Heater
- Endless Hot Water: Our tankless hot water heaters offer unlimited whole-home hot water flow and come equipped with Circ-Logic for pairing with an external pump to reduce wait time for hot water via scheduled or on-demand recirculation
- Energy and Space Efficient: The tankless design of this small hot water heater saves on space and conserves energy as it heats only when necessary
- Optimal Water Pressure: With a hot water flow rate of up to 11 GPM, this tankless water heater provides a powerful, constant stream that can accommodate up to 7 appliances at once
- Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to locate a qualified technician in your area to install your water heater; We do not recommend installing a water heater without a technician
- Guaranteed to Last: 15-, 5-, and 1-year residential for heat exchanger, labor, and parts, respectively; Wifi monitoring available with Controlr module (not included)
- Capacity: Up to 11 GPM
- Power Source: Gas Powered
- Efficiency Rating: 96%
- Installation Type: Indoor (Wall Mounted)
- Dimensions: 22.05 L x 14.76 W x 33.86 H inches
Enjoy an amazing hot water rate of up to 11 gallons per minute with the Rinnai RU199iN Tankless Water Heater. This natural gas heater enables homeowners to enjoy an efficient tankless water heating option without the complicated installation process.
You can enjoy a steady supply of hot water with no waiting around. Its Circ-Logic Instant Heating technology offers continuous hot water on demand without allocating space for storage tanks as it only activates when necessary.
It offers increased efficiency to your home by supplying hot water to up to 7 appliances. A reliable and economical choice, this product is designed for indoor use only.
- Optimal water flow of 11 GPM
- Instant heating technology
- Easy to install
- Compact and durable
#2. Best Budget: EcoSmart ECO 27 Tankless Water Heater
- Endless on-Demand Hot Water; Consistent hot water when you need it that never runs out; Continuously monitored water temperature and controlled flow rates ensure efficiency and consistent performance within 1 degree of selected temperature
- Save Space; EcoSmart tankless electric water heaters are 90% smaller than traditional tank heaters; may be installed on wall or at point of use; Dimensions 17 x 17 x 3.75 inches
- Save Energy; EcoSmart tankless electric water heaters are 99% thermal energy efficient; Only heats water when called unlike a tank heater that maintains water temperature even when not being used. Save up to 50% in water heating costs according to the Department of Energy
- EcoSmart ECO 27 Sizing; Refer to the sizing map. Requires 3x40 AMP Double Pole Breaker, 27-kilowatt tankless electric water heater ideal for providing hot water for whole home applications; provides between 2.7 and 6.5 gallons-per-minute depending on the inlet water temperature; refer to the sizing guide to select the proper solution
- Warranty and Certifications; Limited Lifetime Warranty on electronics, exchanger and element; UL-499 certified; ETL Listed
- Capacity: 3 GPM
- Power Source: Corded Electric
- Efficiency Rating: 99.8%
- Dimensions: 17 L x 3.5 W x 17 H inches
With the EcoSmart Tankless Water Heater, you can save both time and money. Its 6.5 gallons per minute output ensures that you never run out of hot water even during peak usage periods. Plus, its energy efficiency reduces your monthly utility costs with no need to waste excess energy heating large bulky tanks of stored water. Enjoy maximum savings while reducing your environmental impact at the same time!
ECO 27 Tankless Water Heater ensures a safe and enjoyable hot water experience with its high-performing 27kW of power, which has been certified by the reputable Water Quality Association. Consumers can rest assured knowing this certification promises peak performance in terms of health standards and quality control.
- Excellent efficiency rating
- WQA & NSF certified
- 90% smaller than traditional tank heaters
- The heater must be installed by a licensed electrician and/or plumber for warranty claims
#3. Best Portable: Hike Crew Propane Water Heater
- PORTABLE OUTDOOR WATER HEATER – Innovative System Runs on Propane Gas Tank to Heat Water for Showering, Washing Dishes, Cleaning Hands & Other Tasks
- COMFORTABLE CAMPSITE SHOWERS – Includes Water Temperature Control Knob, Hand Faucet/Spigot & Shower Head Attachment w/  Adjustable Spray Patterns
- PUMP & HEAT ON-THE-GO – Connect AC/DC Adapter to Outlet or 12V Cigarette Lighter to Car for Instant Hot Water; Perfect for Camping, Fishing, Hiking & Hunting
- AUTOMATIC SAFETY SHUTOFF – Smart Technology Turns Off the Gas Burner When Water Reaches 142-149 °F; Water Flow Sensor & Fuse & Tilt Protection for Added Safety
- CONVENIENT COMPACT DESIGN – Travel Friendly Heater Arrives With Adapters, Hoses, Attachments & Accessories in a Handy Carry Bag [Propane Not Included]
- Capacity: 1 GPM
- Power Source: Propane Gas
- Power Input: 42,000 BTUs
- Dimensions: 9.65 L x 12.2 W x 11.8 H inches
The Hike Crew Propane Water Heater is the perfect solution for campers and adventurers who don’t want to waste time heating water. It’s designed with portability in mind, so you can easily store it without taking up too much space.
It offers a powerful 2.2L per minute flow with 12V/5A DC input voltage for convenience and ease of use. The water heater features digital panel control and spray pattern control, giving you all the precision you need. You can easily adjust the temperature via the digital panel to ensure your water is always at just the right level of hotness.
Spray pattern control allows each nozzle on the heater to have its own individual flow rate and give exact amounts of water according to your needs.
- Convenient & compact design
- Auto safety shutoff
- Adjustable spray patterns
- Suitable for light-duty use only
#4. Best Electric: Stiebel Eltron Tankless Heater
- On-demand, continuous and unlimited supply of hot water
- Sleek design saves space and no venting required
- Electronic switch activated for virtually silent operation. Phase- single 60 Hz. Voltage- 208 V. Wattage- 27 kW
- Copper sheathed heating element housed in copper cylinder
- 7 Years leakage and 3 years parts complete warranty
- Capacity: 7.5 GPM
- Power Source: Electric
- Power Input: 92,000 BTUs
- Dimensions: 4.63 L x 16.63 W x 14.5 H inches
With Stiebel Eltron’s Tankless Heater, you’ll never have to worry about running out of hot water ever again. With an impressive 7.5 GPM, you can be sure that it’ll meet all of your hot water needs quickly and efficiently — without any exhaust or venting required!
The copper cylinder construction not only makes sure that heat is efficiently dispersed throughout your space, but it also runs virtually silently when in operation. Forget about hearing clunky and loud rattles each time you turn on the heater.
- 99% energy efficiency rating
- Silent Operation
- Convenient digital display
- Requires a 3-phase electric system
#5. Best for Outdoor: Rinnai V53DeN Natural Gas Tankless Water Heater
- Endless Hot Water: Our tankless hot water heaters let you enjoy unlimited hot water flow throughout the house with a compact and durable design that fits your home and lifestyle
- Energy and Space Efficient Tankless Gas Water Heater: This small hot water heater conserves energy, only heating when necessary; Enhanced scale detection lessens possibility of serious, long-term damage to unit
- Optimal Water Pressure: This tankless water heater offers a high-performance hot water flow rate up to 5.3 GPM for a powerful, constant stream that serves up to 4 appliances at once
- Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to locate a qualified technician in your area to install your tankless water heater; We do not recommend installing a water heater without a technician
- Guaranteed to Last: 10-, 5-, and 1-year residential factory warranty for heat exchanger, labor, and parts, respectively
- Capacity: 5.3 GPM
- Power Source: Gas
- Dimensions: 7.9 L x 14 W x 21.8 H inches
This Natural Gas Tankless Water Heater provides high-efficiency operation in even the most extreme outdoor conditions, delivering up to 5.3 GPM of hot water with no excess waste of electricity or resources. With its impressive energy savings and easy installation, you’ll enjoy peace of mind knowing your home is well taken care of – outdoors and in!
It offers the ultimate convenience with its Circ-Logic technology and supports up to three different appliances at the same time. Perfect for smaller to medium-sized homes thanks to its compact, space-saving design and efficient performance.
- Space-saving design
- Optimal water pressure
- Cric-logic technology
- Venting is very expensive
Here are some tips to help you maintain your tankless water heater and extend its life:
- Check the water pressure: Tankless water heaters require a minimum water pressure of 45 psi to work properly. Low water pressure can cause a decrease in water temperature, as well as cause damage to the water heater. Check the pressure periodically to make sure it is adequate.
- Flush the tankless water heater: Flushing your tankless water heater removes sediment and other debris that can build up over time. Flushing the water heater once or twice a year can help keep it running efficiently and extend its life.
- Inspect the venting: The venting on a tankless water heater needs to be inspected regularly to make sure it is free from blockages. Blockages can cause inadequate ventilation, which can lead to the system not working properly.
- Clean the air filter: Tankless water heaters have an air filter that needs to be changed regularly. This helps to keep the system running efficiently and prevents dust and dirt from entering the system.
- Inspect the burner: Make sure the burner is free from any dirt or debris that can restrict the flow of gas. If the burner needs to be cleaned, do so carefully.
The Rinnai RU199iN is an excellent choice for those looking for a reliable, efficient, and cost-effective tankless water heater. Its high-efficiency rating and convenience make it the perfect choice for any home. Moreover, its advanced technology and durability make it a great long-term investment. For these reasons, I highly recommend the Rinnai RU199iN as the best tankless water heater on the market.
A good Energy Factor Rating for a water heater is generally considered to be above 0.70, as this indicates an efficient appliance in terms of energy usage. A higher rating implies that the appliance has a lower operational cost with regard to fuel consumption and is likely to provide greater savings on utility bills.
Additionally, a high Energy Factor Rating implies lesser environmental impact due to decreased energy consumption and reduced greenhouse gas emission as compared to appliances with lower ratings.
Tankless water heaters, while advantageous in many respects, do have a notable downside. The primary downside of a tankless water heater is its inability to keep up with multiple, simultaneous hot-water demands. With most tankless water heaters, only one hot water fixture can be in use at a time; if more than one fixture is running concurrently, the demand for hot water may exceed the heater’s capacity and result in insufficient hot water pressure or temperature.
It is recommended that tankless water heaters be drained at least once every 6 months in order to ensure optimal performance and lifespan. This will help to avoid the buildup of sediment and other impurities that can impede the efficiency of the heater. Furthermore, regular draining can reduce the risk of corrosion, which may lead to operational malfunction or failure.