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Difference Between Condensing and Non Condensing Tankless Water Heater

The main difference between condensing and non condensing tankless water heater is condensing tankless water heaters have two heat exchangers, while non-condensing models only have one. The second heat exchanger in condensing models captures and reuses heat from exhaust gases to preheat incoming cold water, making the condensing models more efficient.

Are you tired of that bulky water heater taking up valuable space in your home? Maybe you’re considering switching to a tankless water heater for its efficiency and on-demand hot water. But did you know there are two main types to choose from? In this comprehensive guide, we’ll break down the differences between condensing vs non-condensing tankless water heaters to help you make the best choice for your home. Then consult our list of the top tankless water heaters!

difference between condensing and non condensing tankless water heater

Understanding Tankless Water Heaters

Before we dive into the condensing vs non-condensing debate, let’s quickly recap what tankless water heaters are all about. Unlike traditional tank-type heaters that store and constantly heat a large volume of water, tankless units heat water on demand. This means you get hot water when needed without wasting energy and keep a tank of water hot all day.

Benefits of Tankless Water Heaters

  • Energy efficiency: They only heat water when needed, reducing standby energy losses.
  • Space-saving: Compact design frees up valuable floor space.
  • Longer lifespan: Typically last 20 years or more, compared to 10-15 years for traditional tank heaters.
  • Endless hot water: Provide a continuous hot water supply as long as demand doesn’t exceed capacity.

Condensing Tankless Water Heaters: The Efficiency Champions

Condensing tankless water heaters are the more technologically advanced option, offering higher efficiency and potentially greater long-term savings.

How Condensing Models Work

Condensing tankless water heaters use two heat exchangers to maximize energy efficiency:

  1. Primary heat exchanger: Heats the incoming cold water using the main burner.
  2. Secondary heat exchanger: Captures and utilizes heat from exhaust gases to preheat incoming water.

This process allows condensing models to achieve a Uniform Energy Factor (UEF) of up to 0.96, meaning they convert up to 96% of the fuel they use into heat for your water.

Advantages and Considerations

Condensing models offer higher energy efficiency, lower environmental impact, and higher flow rates. However, they have a higher upfront cost, more complex installation requirements, and need annual maintenance.

Non-Condensing Tankless Water Heaters: The Traditional Choice

Non-condensing tankless water heaters are the more traditional option, offering simplicity and lower upfront costs.

How Non-Condensing Models Work

Non-condensing tankless water heaters use a single heat exchanger to heat water. They expel hot exhaust gases directly through a venting system without capturing additional heat. This simpler design results in a UEF rating of around 0.80.

Advantages and Considerations

Non-condensing units are generally less expensive to purchase and install, offer simpler installation, and require minimal maintenance. However, they have lower energy efficiency, higher exhaust temperatures requiring more expensive venting materials, and potentially higher long-term operating costs.

Comparing Condensing vs Non-Condensing Models

To help you visualize the differences between condensing and non-condensing tankless water heaters, here’s a comparison chart:

FeatureCondensingNon-Condensing
UEF RatingUp to 0.96Around 0.80
Heat ExchangersTwoOne
Exhaust TemperatureLowerHigher
Venting MaterialPVC or PolypropyleneMetal
Initial CostHigherLower
Long-term Operating CostLowerHigher
Installation ComplexityMore ComplexSimpler
Maintenance NeedsAnnualMinimal
Environmental ImpactLowerHigher
Flow RatesHigherLower

Factors to Consider When Choosing

When deciding between condensing and non-condensing tankless water heaters, consider the following factors:

  1. Household size and hot water demand
  2. Climate
  3. Installation location
  4. Budget
  5. Environmental concerns

Use our free, tankless water heater size calculator for a personalized recommendation.

Installation and Maintenance

Installation Considerations

Proper installation is crucial for both types of tankless water heaters. Key points to remember include venting requirements, condensate drainage for condensing units, gas line capacity, and electrical requirements.

Maintenance Tips

Regular maintenance is essential for optimal performance and longevity. This includes annual professional servicing, flushing to prevent mineral buildup, filter cleaning, and regular inspection of venting systems.

Cost Analysis and Environmental Impact

Long-Term Savings

While condensing units have a higher initial cost, they can lead to significant savings over time. On average, a condensing unit might save about $35 annually in energy costs compared to a non-condensing unit.

Environmental Benefits

Condensing units are more eco-friendly due to their higher efficiency and lower emissions. Over a 20-year lifespan, a condensing unit could reduce your household’s carbon footprint by several tons compared to a non-condensing unit.

Making the Right Choice for Your Home

When to Choose a Condensing Tankless Water Heater

  • Larger households with high hot water demand
  • Looking to maximize energy efficiency and reduce utility bills
  • Colder climate
  • Willing to invest more upfront for long-term savings
  • Reducing your environmental impact is a priority

When to Choose a Non-Condensing Tankless Water Heater

  • Smaller household with moderate hot water needs
  • You’re working with a tighter budget
  • In warmer climates where the efficiency difference is less pronounced
  • You prefer a simpler installation process
  • Limited space for installation

Both condensing and non-condensing tankless water heaters offer significant advantages over traditional tank-type heaters. Your choice will depend on your household needs, budget, and long-term energy efficiency goals. By carefully considering the factors outlined in this guide, you’ll be well-equipped to make the best decision for your home’s hot water needs.

FAQ

What is the downside of a tankless water heater?

While tankless water heaters offer many benefits, they do have some drawbacks:

  • Higher upfront cost compared to traditional tank heaters
  • May require upgrades to your home’s electrical or gas system
  • Can struggle to supply hot water to multiple fixtures simultaneously
  • Potential for longer wait times for hot water at fixtures far from the unit

How long do tankless water heaters last?

Tankless water heaters typically have a longer lifespan than traditional tank heaters. On average, a well-maintained tankless water heater can last 20 to 30 years, about twice the lifespan of a conventional tank-type water heater.

What’s the difference between condensing vs non-condensing tankless water heaters?

Condensing tankless water heaters are more energy-efficient than non-condensing models. They use a second heat exchanger to capture and use heat from exhaust gases, achieving efficiency ratings up to 98%. Non-condensing units are simpler and less expensive but have lower efficiency ratings, around 80-85%. Condensing models also allow for less expensive venting materials but require a condensate drain.

Do tankless water heaters really save money?

Yes, tankless water heaters can save money in the long run through reduced energy costs. While they have a higher initial cost, their energy efficiency can lead to 24-34% savings on your water heating bills compared to traditional tank heaters. However, the actual savings will depend on your household’s hot water usage and local energy prices.