Tankless Water Heaters: How to Evaluate and Choose the Right Model

Nov 21, 2023

Tankless water heaters, also known as on-demand water heaters, have gained popularity for their energy efficiency and space-saving design. Unlike traditional water heaters that store and continually heat water, tankless models heat water directly as it flows through the device, providing hot water only when needed. This article will guide homeowners on how to evaluate different tankless water heater models to choose the one that best suits their needs.

Understanding Tankless Water Heaters

Before diving into the evaluation process, it’s essential to understand how tankless water heaters work. These units use high-powered burners to rapidly heat water as it runs through a heat exchanger, delivering hot water directly to your faucets or shower without the need for a storage tank.


  • Energy Efficiency: By heating water on demand, they eliminate the standby energy losses associated with storage water heaters.

  • Space Saving: Their compact size frees up valuable space in your home.

  • Continuous Hot Water: Ideal for families or high-demand usage, as they can provide hot water continuously.


  • Higher Initial Cost: They are generally more expensive to purchase and install compared to traditional models.

  • Variable Flow Rates: The flow rate can be limited, impacting the simultaneous use of multiple hot water appliances.

Evaluating Tankless Water Heater Models

  1. Fuel Type:

    • Electric or Gas: Electric models are easier and cheaper to install but may have higher operational costs depending on electricity prices. Gas models, while more expensive to install, often have lower operational costs but require proper venting.

  2. Flow Rate (GPM):

    • Measured in gallons per minute (GPM), the flow rate determines how much hot water the unit can produce at a time. Consider your peak hot water demand to choose a model with an adequate flow rate.

  3. Energy Efficiency:

    • Look for the Energy Factor (EF) rating. A higher EF means higher efficiency. Gas models typically have EF ratings between 0.82 and 0.94, while electric models can be more efficient.

  4. Size and Installation:

    • Evaluate the physical size and installation requirements. Some models might require additional space or specific venting arrangements, especially gas-powered units.

  5. Temperature Control:

    • Advanced models offer better temperature control and consistency. Consider models with easy-to-use controls for adjusting the output temperature.

  6. Maintenance and Longevity:

    • Regular maintenance, such as de-scaling and filter cleaning, is crucial for longevity. Check the manufacturer's guidelines and consider the ease of maintenance.

  7. Brand Reputation and Warranty:

    • Research different brands for their reliability and customer service. A robust warranty can be a good indicator of the manufacturer's confidence in their product.

  8. Cost of Operation and Savings:

    • Calculate the potential energy savings and compare them against the higher initial cost to determine if a tankless model is a cost-effective choice for your home.


Choosing the right tankless water heater involves balancing factors like fuel type, flow rate, energy efficiency, and cost. While they offer significant advantages in terms of energy efficiency and space-saving, the initial investment and suitability for your home's hot water demands are crucial considerations. Before making a decision, assess your household's hot water usage patterns, consult with a professional for installation requirements, and consider long-term operational costs. With the right model, a tankless water heater can be a valuable addition to your home, providing efficient and reliable hot water for years to come.

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