Comparing Condensing vs. Non-Condensing Tankless Water Heaters

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 buy a tankless water heater.

Key Differences in Operation

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.

Fundamental Design

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

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

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. 

Price Comparison

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

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.

Life Span

Both condensing and non-condensing water heaters have a life span 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.

Pros and Cons Summary

A tankless water heater is no small investment. It's important to know all of the benefits and disadvantages of both tankless water heater types to make the most informed decision. Here are the pros and cons of tankless water heaters by type.

Condensing Water Heater Pros:

• More energy efficient

• Savings on your electric bills

Condensing Water Heater Cons:

• Higher upfront cost

• More maintenance

• Larger size 

Non-condensing Water Heater Pros:

• Lower upfront cost

• Less maintenance

• Smaller size 

Non-condensing Water Heater Cons:

• Less energy efficient

• Higher electric bills 

How to Determine Which Is Right for Your Home?

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?

Should You Contact a Pro to Install a Water Heater?

So you've made up your mind about which tankless water heater you want. But before you roll up your sleeves to install a water heater yourself, know that this installation is not an easy DIY project. To correctly install a water heater, consider contacting a tankless water heater installer near you. 

Questions to Ask a Water Heater Installation Pro

When you decide to replace your conventional water heater with a tankless water heater, we suggest getting quotes from multiple water heater installation pros in your area. Fielding multiple quotes can help you choose a contractor with the most competitive pricing, the timeline that best suits your needs, and/or the customer reviews that give you the most confidence in their abilities.

As you procure these quotes, it’s important to ask the water heater pros some questions to help you make your decision. You’ll also want to ask additional questions before, during, and after the installation to ensure you know what to expect and how to maintain your new water heater system.

Here are some questions to consider:

• Is your company licensed and insured to perform this type of service? Is the contractor who will do the actual work licensed and installed?

• Does a tankless water heater make sense for my home? Do you recommend a condensing or a non-condensing tankless water heater, and why? What size do you recommend for my home?

• Does your work come with any labor guarantees? Does the water heater you’re installing come with any warranties?

• How soon can your company begin the installation, and how long will it take?

• Do I need to obtain a permit for this water heater installation? Is that something your company handles, and is the cost built into your estimate already?

• Is there anything I need to do to prepare for the installation?

• Does the model of water heater we’re installing qualify for any federal or state tax credits?

• How do I maintain the tankless water heater? Can you walk me through the various tankless water heater components, how they work, and how I can care for them? Are there certain tasks I, as a homeowner, shouldn’t do myself? Does your company offer routine water heater maintenance services?