Condensing vs. Non-Condensing Tankless Water Heaters: What’s the Difference?

 If you’re ready to swap out a conventional water heater, choosing a tankless water heater is a solid investment. According to Energy Saver, tankless water heaters are 8% to 34% more energy efficient, depending on your water consumption and the type of tankless water heater you choose. 

To help you decide, we’ve rounded up condensing vs. non-condensing tankless water heaters to show several key differences worth considering before you hire a local water heater pro to install a tankless water heater.

What Are the Differences Between Condensing and Non-Condensing Tankless Water Heaters?

While both condensing and non-condensing tankless water heaters produce hot water on demand, several differences could make either one the best tankless water heater for your home, depending on the circumstances. Let's break down these differences to help you decide which water heater is right for your home.

Design Differences

As the name suggests, a condensing tankless water heater uses condensation as part of the heating process. This water heater has an extra heat exchanger to recycle heat and continuously heat cold water, and provide hot water to your home. 

Unlike condensing tankless water heaters, non-condensing water heaters lack that extra heat exchanger. This means that heat is not recycled. Instead, any heat leaves the unit through a ventilation system, which releases the gases outside your home. 

Energy Consumption Differences

Since condensing tankless water heaters recycle and reuse heat produced through combustion, they’re far more energy-efficient than non-condensing tankless water heaters. With a non-condensing water heater, a large amount of the energy generated to produce the heat goes to waste without that secondary recovery.

Size Differences

The size of your water heater plays a role in determining whether you can even have that water heater in your home in the first place. Condensing tankless water heaters take up more room than non-condensing tankless water heaters due to their additional heat exchangers. This could be an issue for smaller homes or homes that don't have enough space to accommodate a larger unit. 

Cost Differences 

Tankless water heaters cost anywhere between $1,400 and $3,825 on average. Since condensing tankless water heaters contain an extra mechanism for recycling heat, they tend to cost more than non-condensing tankless water heaters. 

At the same time, condensing tankless water heaters consume less energy, so you will save some money on the cost of your electric bills. These savings help offset the upfront cost of your condensing tankless water heater in the long run. 

You also need to factor in the cost of installing the venting unit for a non-condensing tankless water heater. The venting uniting costs more than ventilation for a condensing tankless water heater due to the condensing tankless water heater’s cooler exhaust gas.

Maintenance Differences

Tankless water heaters don't generally require much maintenance. Still, it's important to keep in mind that condensing tankless water heaters require more maintenance because they have that extra heat exchanger and a more complicated design. Non-condensing tankless water heaters don't need a drain, but condensing tankless water heaters do need you to know how to drain a water heater to remove excess condensation. On average, the cost to flush a water heater runs $150 to $250 for tankless units.

 Lifespan Differences

Both condensing and non-condensing water heaters have a lifespan of 15 to 20 years. To ensure your water heater lasts as long as possible, perform proper maintenance and have a professional inspect and service it annually.

Should You Get a Condensing or Non-Condensing Tankless Water Heater?

Every home is different, making it a little tricky to know which tankless water heater is the best fit for your home. To determine which tankless water heater is best for your house, ask yourself the following questions: 

• What is your budget?

• How important to you is maximizing energy efficiency and energy savings?

• Are you prepared to maintain and drain a condensing tankless water heater?

• How much space does your home have to accommodate a tankless water heater?