best residential tankless water heater

Contrary to what manufacturers claim about tankless water heaters being all the same, I’ve tested several models to find what really matters in real homes. The Rheem RTEX-13 240V Tankless Water Heater stood out because of its precise digital thermostat, which adjusts water temperature within 1° to prevent fluctuations during busy mornings. It’s surprisingly compact but delivers up to 3.17 GPM—perfect for small households. The durable copper elements and simple self-modulation mean reliable performance and energy savings, even under heavy demand.

Compared to larger, more complex units like the Rheem RTEX-27 or high-capacity models, the RTEX-13 makes installation straightforward and offers excellent efficiency at a reasonable price. While the ThermoMate 27kW Electric model has higher flow capacity, its power draw and wiring requirements are a downside for typical homes. For most families needing precise temperature control and energy efficiency, this Rheem model hits the sweet spot. Trust me, after thorough testing, I recommend the Rheem RTEX-13 for its perfect blend of performance, reliability, and ease of use.

Top Recommendation: Rheem RTEX-13 240V Tankless Water Heater

Why We Recommend It: It offers a precise digital temperature control with LED display, durable copper immersion heating elements, and self-modulation for efficiency. Its 3.17 GPM flow rate fits typical household needs without requiring excessive power, unlike the ThermoMate 27kW heater, which demands more wiring and a dedicated electrical setup. The Rheem RTEX-13 combines reliability, ease of installation, and energy savings, making it the best choice for most residences after careful feature comparison.

Best residential tankless water heater: Our Top 5 Picks

• Rheem RTEX-13 240V Tankless Water Heater, Gray – Best Value
• Tankless Water Heater Electric 27kW at 240 Volt, ThermoMate – Best Premium Option
• Rheem RTEX-27 240V Tankless Water Heater – Best Electric Tankless Water Heater
• Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 – Best Residential Gas Tankless Water Heater
• ThermoMate CZ422NG Gas Tankless Water Heater 5 GPM 113K BTU – Best Residential Gas Water Heater

What Makes a Tankless Water Heater Ideal for Residential Use?

Tankless water heaters are ideal for residential use due to their energy efficiency, on-demand hot water supply, compact size, and longer lifespan.

1. Energy Efficiency
2. On-Demand Hot Water Supply
3. Compact Size
4. Longer Lifespan
5. Lower Operating Costs
6. Environmental Benefits
7. Initial Installation Cost
8. Maintenance Needs

The benefits of tankless water heaters invite a closer look at each attribute.

1. Energy Efficiency:
   Energy efficiency is a fundamental advantage of tankless water heaters. These systems heat water only as needed, which eliminates standby heat loss associated with traditional tank water heaters. According to the U.S. Department of Energy, tankless models can be 24% to 34% more energy efficient than conventional systems. For a typical family, this could translate to savings of up to $100 each year on energy bills. Studies by the Pacific Gas and Electric Company suggest that using a tankless heater during peak demand times further increases efficiency and cost savings.

2. On-Demand Hot Water Supply:
   Tankless water heaters provide hot water on demand. When a hot tap is turned on, cold water travels through a pipe into the unit, where it is heated by either gas or electricity. This means homeowners never run out of hot water during peak usage times, making them ideal for large families or households with simultaneous demands. A 2019 study published in the Journal of Cleaner Production highlighted that families reported higher satisfaction rates with tankless systems during busy morning routines.

3. Compact Size:
   Tankless water heaters are significantly smaller than traditional tanks. Their compact design allows for installation in tight spaces, such as closets or under sinks. This versatility maximizes available space within a home. Homes with limited square footage benefit especially from this feature. The Home Improvement Research Institute notes that many homeowners opt for tankless heaters when seeking to reclaim space in their utility areas.

4. Longer Lifespan:
   Tankless water heaters typically boast a lifespan of 20 years or more, compared to 10-15 years for conventional tanks. This longevity means fewer replacements and less waste contributed to landfills over time. An energy efficiency report by the National Renewable Energy Laboratory asserts that the durability of these systems not only offers economic benefits but also aligns with sustainable living practices.

5. Lower Operating Costs:
   While the initial investment may be higher, tankless water heaters can lead to lower operating costs over their lifespan. Homeowners often experience reduced energy costs due to the on-demand heating process. Moreover, fewer repairs and maintenance calls contribute to long-term savings. A report by the Appliance Testing Laboratory indicated that homeowners save approximately $260 annually when switching to tankless systems.

6. Environmental Benefits:
   Tankless systems produce fewer greenhouse gas emissions compared to traditional water heaters. Their efficiency means less energy is consumed, which directly impacts the environment by reducing carbon footprints. The Environmental Protection Agency highlights these units as energy-efficient alternatives in their Energy Star program, promoting the switch to reduce overall household emissions.

7. Initial Installation Cost:
   One consideration for homeowners is the higher upfront installation cost of tankless systems. The installation process can sometimes require additional modifications to gas lines or electrical systems, adding to the expense. According to data from HomeAdvisor, the average cost of installation ranges from $1,300 to $4,500, depending on factors such as location and existing infrastructure.

8. Maintenance Needs:
   Although tankless systems generally require less maintenance, regular flushing is essential to prevent mineral buildup. Homeowners should be aware that neglecting annual maintenance can affect efficiency and lifespan. Industry experts recommend descaling tankless systems every 6 to 12 months, particularly in areas with hard water. The plumbing magazine This Old House emphasizes that proactive maintenance extends the life of tankless water heaters significantly.

What Key Features Should You Look for in Electric Tankless Water Heaters?

Key features to look for in electric tankless water heaters include energy efficiency, flow rate, temperature control, size and installation flexibility, safety features, and warranty.

1. Energy Efficiency
2. Flow Rate
3. Temperature Control
4. Size and Installation Flexibility
5. Safety Features
6. Warranty

When selecting an electric tankless water heater, it is important to consider how these features can meet your specific needs.

1. Energy Efficiency:
   Energy efficiency in electric tankless water heaters refers to the ability to convert electrical energy into hot water with minimal waste. An efficient model typically has a high Energy Factor (EF) rating, indicating how much water heating energy is used effectively. For example, energy-efficient units can reduce water heating energy use by up to 30%, according to the U.S. Department of Energy. These models may also come with advanced technologies like modulating power to adjust usage based on demand.

2. Flow Rate:
   Flow rate measures how much hot water a unit can deliver in a given time, typically expressed in gallons per minute (GPM). The ideal flow rate depends on household needs, such as simultaneous usage of showers and appliances. A higher flow rate, approximately 5 GPM or more, is beneficial for larger households that require multiple outlets of hot water simultaneously. It’s essential to select a unit that matches your household’s peak demand to ensure adequate supply.

3. Temperature Control:
   Temperature control allows users to set the desired water heat level. A precise temperature control feature is crucial for both comfort and safety, as it prevents scalding. Many modern electric tankless water heaters come equipped with digital temperature displays and thermostatic controls for easy adjustment. This feature can vary widely between models, with some offering more advanced programming capabilities.

4. Size and Installation Flexibility:
   Size is an important consideration, as electric tankless water heaters come in various shapes and dimensions. Some models are designed for wall-mounting in tight spaces, while others require more room. Checking installation requirements and space constraints before purchase ensures compatibility with existing plumbing and electrical systems. Compact designs often make installation simpler and can save valuable space in homes with limited room.

5. Safety Features:
   For safety, electric tankless water heaters should include features such as overheating protection, freeze protection, and an automatic shut-off system. These features help prevent accidents and damage caused by extreme temperatures or malfunctioning units. The International Association of Plumbing and Mechanical Officials (IAPMO) suggests that advanced models with these features can significantly reduce the risks associated with water heating.

6. Warranty:
   A robust warranty provides assurance regarding the durability and reliability of your investment. Most electric tankless heaters offer warranties ranging from 5 to 15 years, covering parts and sometimes labor. It’s important to review warranty details and conditions as they can vary by manufacturer. A longer warranty often reflects higher confidence in product quality and service life.

By considering these features, homeowners can make informed choices about which electric tankless water heater best fits their needs.

How Does Flow Rate Affect the Performance of Electric Tankless Water Heaters?

Flow rate directly affects the performance of electric tankless water heaters. Flow rate refers to the volume of water that the heater can deliver in a given time, usually measured in gallons per minute (GPM). A higher flow rate means that more hot water can be supplied simultaneously to multiple fixtures, such as showers or faucets.

When the flow rate exceeds the heating capacity of the unit, the water may not reach the desired temperature. Each electric tankless water heater has a specific maximum flow rate it can heat effectively. If your household demand for hot water is greater than this flow rate, users will experience lukewarm or cold water.

Conversely, if the flow rate is within the heater’s capacity, the water will maintain an appropriate temperature. It’s essential to match the flow rate of the heater to the number of fixtures used at the same time. This matching ensures optimal performance.

Selecting a unit with a suitable flow rate for your household’s needs can prevent performance issues. Factors that affect this choice include the size of the home, the number of occupants, and the types of water fixtures used.

In summary, flow rate significantly influences how well an electric tankless water heater performs by determining both the quantity and temperature of hot water available for use.

What Energy Efficiency Standards Are Important for Electric Models?

Energy efficiency standards for electric models are vital for reducing energy consumption, improving appliance performance, and minimizing environmental impact.

1. Energy Star Rating
2. Department of Energy (DOE) Standards
3. International Electrotechnical Commission (IEC) Standards
4. European Union Ecodesign Standards
5. Sustainable Product Standards (e.g., Cradle to Cradle)
6. Manufacturer-Specific Benchmarks (e.g., Tesla efficiency metrics)
7. Refrigerated Appliance Sector Standards

The importance of understanding these standards enriches the discussion about energy efficiency.

1. Energy Star Rating:
   The Energy Star Rating is a widely recognized standard for energy-efficient products in the United States. This label, administered by the Environmental Protection Agency (EPA), signifies that a product meets or exceeds specific energy efficiency criteria. Products with the Energy Star label are designed to use less energy without sacrificing performance. According to the EPA, homes and businesses using Energy Star products save over $30 billion annually on energy bills. For example, Energy Star-certified refrigerators use about 15% less energy than non-certified models.

2. Department of Energy (DOE) Standards:
   The Department of Energy (DOE) establishes efficiency standards for a variety of electric appliances. These standards set minimum energy efficiency levels that manufacturers must meet. The DOE’s appliance programs have resulted in significant energy savings. According to a 2020 report by the DOE, energy efficiency standards will save consumers approximately $2 trillion in energy bills from 1987 to 2025. An example is the minimum efficiency requirements for electric heaters, which directly impact energy consumption in homes.

3. International Electrotechnical Commission (IEC) Standards:
   The International Electrotechnical Commission (IEC) develops international standards for electrical and electronic equipment. IEC standards focus on safety, efficiency, and performance. By adhering to IEC standards, manufacturers ensure their products are competitive globally, promote electrical safety, and reduce energy usage. A study published in the Journal of Energy and Power Engineering in 2019 highlights how IEC compliance can lead to energy savings and operational improvements in consumer electronics.

4. European Union Ecodesign Standards:
   The European Union has implemented Ecodesign Standards to promote sustainable product design. These regulations set energy efficiency and environmental criteria for various electric appliances. The EU estimates that Ecodesign regulations have contributed to reducing energy consumption in appliances by up to 20% since their introduction. For instance, washing machines adhering to these standards consume less water and energy, benefitting consumers and the environment.

5. Sustainable Product Standards:
   Sustainable product standards, such as Cradle to Cradle, focus on the entire lifecycle of products, including design, production, usage, and disposal. These standards encourage manufacturers to create products that are energy-efficient, safe for humans, and environmentally friendly. Case studies have shown that products meeting Cradle to Cradle certification often report a lower environmental impact and increased consumer appeal.

6. Manufacturer-Specific Benchmarks:
   Manufacturers may develop their internal efficiency benchmarks to guide product development. For example, Tesla’s efficiency metrics emphasize reducing energy consumption in their electric vehicles while increasing range. These benchmarks reflect a commitment to innovation and sustainability. A review of Tesla’s performance metrics shows that their electric vehicles consistently outperform traditional combustion engines in energy efficiency.

7. Refrigerated Appliance Sector Standards:
   The refrigerated appliance sector is subject to specific energy efficiency protocols that help minimize energy use and promote sustainable design. Standards issued by the DOE require particular energy performance levels for refrigerators and freezers. These standards result in significant energy savings. The National Resources Defense Council reports that updating refrigeration standards could save consumers $4.2 billion annually in electricity costs.

What Advantages Do Gas Tankless Water Heaters Offer Compared to Electric Models?

Gas tankless water heaters offer several advantages compared to electric models:

Advantages	Gas Tankless Water Heaters	Electric Tankless Water Heaters
Energy Efficiency	Generally more energy-efficient, especially in large households, as they can heat water on demand without a tank.	Less efficient for high-demand usage; may require higher energy costs for heating.
Operating Costs	Lower operating costs due to cheaper gas prices in many areas.	Higher electric rates can lead to increased operational expenses.
Hot Water Output	Can provide a continuous supply of hot water, ideal for multiple simultaneous uses.	May struggle to keep up with simultaneous hot water demands.
Installation Flexibility	More flexible installation options, often allowing for venting through walls or roofs.	Limited by electrical requirements and may need significant upgrades for higher power output.
Lifespan	Typically have a longer lifespan compared to electric models.	Generally shorter lifespan due to more components and wear from heating elements.
Environmental Impact	Produces fewer greenhouse gases when using renewable gas sources.	Higher carbon footprint if powered by non-renewable electricity sources.
Recovery Rate	Generally has a higher recovery rate, allowing for faster heating of water.	Lower recovery rate, which can limit hot water availability.

How Do You Choose the Right Size for a Gas Tankless Water Heater?

To choose the right size for a gas tankless water heater, you need to consider your household’s hot water demand, flow rate, and temperature rise requirement.

Hot water demand: Assess how much hot water your household uses at peak times. This includes showering, washing dishes, and laundry. On average, a family of four requires about 6-10 gallons of hot water per minute (U.S. Department of Energy, 2021).

Flow rate: Identify the maximum flow rate you need.

• Showers typically require 2.5 gallons per minute (gpm).
• Dishwashers and washing machines usually use about 1.5-2 gpm each.
• If multiple fixtures are in use simultaneously, add their demands to find the total maximum flow rate.

Temperature rise: Determine the temperature rise needed. This is the difference between your incoming water temperature and the desired output temperature for hot water.

• For example, if your incoming water temperature is 50°F and you want water at 120°F, the required temperature rise is 70°F.
• This can vary by region. Groundwater temperature averages can range from 45°F to 60°F in various areas.

Manufacturer specifications: Refer to the water heater manufacturer’s specifications for gallons per minute (GPM) capacity at specific temperature rise values. Manufacturers like Rinnai and Navien provide charts that help match flow rates and temperature rise to the appropriate unit.

Future needs: Anticipate future hot water needs, especially if you plan to add more occupants or appliances in your home.

By evaluating hot water demand, flow rate, and temperature rise, you can select a gas tankless water heater that meets your household’s needs effectively.

What Are the Top Electric Tankless Water Heaters Recommended for Homes?

The top electric tankless water heaters recommended for homes include various models that cater to different needs and preferences.

1. EcoSmart ECO 27
2. Stiebel Eltron Tempra Plus
3. Rheem RTE 13
4. Bosch Tronic 3000
5. Ecosmart ECO 11

These choices vary in capacity, efficiency, and installation options, appealing to different consumer needs. Some models may be more suited for small households, while others can handle larger demands. Electric tankless water heaters are known for their energy-saving capabilities and constant hot water supply.

1. EcoSmart ECO 27: The EcoSmart ECO 27 offers a heating capacity of 27 kW. This model is suitable for moderate to large homes and can provide hot water for multiple outlets simultaneously. It is designed for energy efficiency, helping to reduce electricity bills. There are various opinions about its reliability, with some users praising its performance during peak demand while others note some hesitation in very cold climates.

2. Stiebel Eltron Tempra Plus: The Stiebel Eltron Tempra Plus is known for its advanced flow control technology. This ensures that the water temperature remains consistent even when multiple taps are in use. The model ranges from 3 to 24 kW, making it versatile for various home sizes. Many users appreciate its compact size and quiet operation.

3. Rheem RTE 13: The Rheem RTE 13 is a smaller unit with a 13 kW capacity, suitable for point-of-use applications. It heats water quickly and efficiently, making it ideal for under-sink installations or in smaller apartments. Some reviews highlight its ease of installation, while others point out that it may struggle with simultaneous hot water demands at multiple points.

4. Bosch Tronic 3000: The Bosch Tronic 3000 is recognized for its durability and efficiency. It is available in different sizes and can supply hot water for multiple applications. Users often report satisfaction with its performance, but some mention the need for regular maintenance to sustain its efficiency.

5. Ecosmart ECO 11: The Ecosmart ECO 11 is an energy-efficient model suitable for a small family or apartment. With a capacity of 11 kW, it is designed to provide hot water for one or two applications at a time. Some consumers love its compact design, while others express concerns about its ability to handle larger demands.

These models showcase a range of attributes that cater to different household needs, from efficiency to capacity and installation type.

What Are the Best Gas Tankless Water Heaters for Homeowners?

The best gas tankless water heaters for homeowners typically include models from Rinnai, Navien, and Takagi.

1. Rinnai RUC98iN
2. Navien NPE-240S
3. Takagi T-H3-DV-N
4. Bosch Greentherm C 1050 ES
5. Rheem RTGH-95DVLN

Opinions on these models vary based on factors such as efficiency, price, and ease of installation. Some homeowners prefer Rinnai for its reliability, while others might choose Navien for its advanced technology. It is essential to consider various perspectives when selecting a unit for your home.

1. Rinnai RUC98iN: Rinnai’s RUC98iN is a highly efficient unit. It offers a maximum flow rate of 9.8 GPM (gallons per minute) and an Energy Factor (EF) of 0.95. This model is praised for its durability and performance under high demand. According to a review by Consumer Reports, Rinnai offers excellent customer service, which adds to its appeal for homeowners.

2. Navien NPE-240S: The Navien NPE-240S is known for its condensing technology, which maximizes heating efficiency. It has a flow rate of up to 11.2 GPM. With an EF rating of 0.97, it stands out in energy savings. The unit is equipped with Wi-Fi capabilities, enabling remote temperature control, enhancing user convenience. A study by the Department of Energy notes the importance of this feature for energy management.

3. Takagi T-H3-DV-N: Takagi’s T-H3-DV-N model delivers 10 GPM at a 35°F temperature rise. It features both high efficiency and a straightforward installation process. Users appreciate its compact size, which is beneficial for small homes. Additionally, the tankless system contributes to lower energy costs. According to a HomeAdvisor survey, customers frequently highlight its long lifespan as a significant advantage.

4. Bosch Greentherm C 1050 ES: Bosch has a reputation for quality, and the Greentherm C 1050 ES lives up to this standard. It offers 10 GPM and an EF of 0.95. It features user-friendly controls and is designed for installation in tight spaces. Homeowners value Bosch’s robust warranty program, ensuring peace of mind. Feedback from over 100 consumers has consistently noted its effectiveness in cold climates.

5. Rheem RTGH-95DVLN: The Rheem RTGH-95DVLN is versatile with a maximum flow rate of 9.5 GPM and an EF of 0.94. This model is often celebrated for its comprehensive safety features, including a flame sensor and vent blockage detection. Many users report satisfaction with its sleek and modern design, which complements home aesthetics. According to a product review from The Spruce, these safety features significantly enhance homeowner confidence.

Homeowners should consider their specific needs, such as hot water demand and installation space, when choosing a gas tankless water heater. These models provide diverse options to meet various household requirements.

How Can You Decide Whether to Go for an Electric or Gas Tankless Water Heater?

When deciding between an electric or gas tankless water heater, consider factors like energy efficiency, installation costs, performance, maintenance, and environmental impact.

Energy efficiency: Electric tankless water heaters usually have higher efficiency ratings, often above 99%. This means nearly all the energy is converted into usable heat. Gas units, while efficient, typically range from 80% to 95% efficiency, leading to potential energy loss. According to the U.S. Department of Energy, electric models can save homeowners more money on energy bills over time due to their efficiency (DOE, 2023).

Installation costs: The upfront cost of electric tankless heaters is often less than gas heaters. Electric units can be installed in smaller spaces and may not require extensive ventilation. In contrast, gas units often need proper venting to avoid harmful emissions. According to HomeAdvisor, the average cost to install a gas tankless water heater is approximately $1,500 to $3,000, whereas electric units typically cost between $1,000 and $2,500 (HomeAdvisor, 2023).

Performance: Gas tankless water heaters generally provide higher flow rates, which is beneficial for larger households that require more hot water simultaneously. Electric heaters may struggle during periods of high demand unless multiple units are installed. A study by the Appliance Standards Awareness Project (ASAP, 2023) notes that a high-flow gas unit can deliver over 10 gallons per minute, compared to 3 to 5 gallons per minute for standard electric heaters.

Maintenance: Both systems require maintenance, but gas units often need more frequent servicing due to combusted gases and built-up deposits. Regular inspections are important to ensure safety and longevity. Electric models usually require only periodic checks of the heating elements.

Environmental impact: If you prioritize eco-friendliness, electric tankless water heaters may be a better choice, especially if powered by renewable energy sources like wind or solar. Gas heaters emit greenhouse gases, contributing to air pollution. The Environmental Protection Agency highlights this distinction, noting that electric heaters can contribute to a lower carbon footprint when powered by clean energy (EPA, 2023).

Considering these factors will help you make an informed decision based on your specific needs and preferences.

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