For decades, there was really only one style of heat exchanger for tankless water heaters. But within the past several years, stainless steel heat exchangers have risen in popularity, and with good reason, for the most part. But what are the downsides?
After spending over 15 years installing tankless water heaters, we’ve seen the industry and technology evolve. While copper heat exchangers are still an easy recommendation for many homeowners, some people want the latest and greatest. But as with anything, stainless steel heat exchangers aren’t perfect.
In this article, we’ll run through what stainless steel heat exchangers do and don’t do well, so you can make a more informed decision about what style tankless water heater is best for your home.
Before we jump in, let’s get an overview of the pros and cons of a stainless steel heat exchanger.
The pros of a stainless steel heat exchanger include:
- Warranty
- Longevity
- Hard water resistance
- Efficiency
Conversely, the cons of a stainless steel heat exchanger include:
- Doesn’t heat up as quickly as copper
- False sense of security
- Price
Let’s run through each pro and con, so you get get the full picture.
Pros of Stainless Steel Heat Exchangers
Warranty
A standard tankless water heater is 12 to 15 years, but models with a stainless steel heat exchanger crush those terms. Most stainless steel core tankless water heaters carry a warranty of 15 to 25 years, ensuring your investment is safe for much longer than the norm.
Like anything in the tankless water heater world, warranty terms will vary based on the model. While some brands and models reach the maximum 25-year term, others may not. But now you know what the pinnacle of a tankless water heater warranty looks like.
Longevity
Going hand-in-hand with warranty terms is the tankless water heater’s longevity in terms of lifespan. Stainless steel heat exchangers are proven to outlast copper core tankless water heaters.
A major reason for this disparity is that copper corrodes more easily than stainless steel. The faster corrosion rate means fewer years of service, potentially more breakdowns, and a harder time finding replacement units for older models.
But there’s another specific reason stainless steel heat exchangers can outlast copper ones so easily.
Hard Water Resistance
There are countless counties across the country that have hard water. Many people only think of the visible impacts of hard water, like weaker nails, damaged hair, or streaky dishes, but hard water also impacts your plumbing system. Your tankless water heater is also included in the laundry list of affected items.
Stainless steel heat exchangers boast the benefit of being more resistant to the pitfalls of hard water. This means more time in service and fewer breakdowns. But this sense of security can backfire, as we’ll talk about in the cons section.
Efficiency
Switching gears into another huge win for stainless steel tankless heat exchangers, let’s look at efficiency. Stainless steel core tankless water heaters are the cream of the crop when it comes to efficiency.
Because many stainless steel core models are their manufacturer's top performers in terms of efficiency, they also qualify for the maximum California rebates and federal tax credits. So, on top of getting some money back in your pocket from the government, you’ll also save on your monthly bills to a small degree.
With all of the bright spots of stainless steel heat exchangers taken care of, let’s take a look at the issues that might give you pause during your decision-making so you can temper expectations.
Cons of Stainless Steel Heat Exchangers
Copper Heats Quicker
Despite being the new kid on the block, stainless steel heat exchangers don’t completely outpace their predecessors. One pitfall of stainless steel heat exchangers is that they’re not as conductive as copper core models.
Copper heats faster than stainless steel and, therefore, transfers heat better. This means your water heats up faster with a copper heat exchanger. You’d notice this disparity in the additional few seconds it takes the water from your tap to get up to temperature.
This pitfall isn’t the biggest letdown, but it can make a difference for people who want to squeeze out every ounce of performance for their dollar. But there are still issues that can lead to larger problems in the long run.
False Sense of Security
We mentioned in the pros section that stainless steel water heaters’ resistance to hard water can cause a false sense of security. Because you can get away with improper maintenance, like skipping a yearly check-up or skimping out on water treatment, for a period of time, many homeowners forget that they still need to take care of their tankless water heater.
Going a year without proper maintenance or negating water treatment can cause your tankless water heater to break down. Despite being more durable than a copper core model, you still need to practice proper maintenance to ensure your tankless water heater stays under warranty and is in working condition.
Higher Price
Like anything new and shiny, you’ll have to pay more if you want the latest and greatest technology. Stainless steel heat exchangers are no different in this department. On average, you’re looking at a premium of about $500 to $1,000 over a copper core model.
You can look to the longer lifespan and warranty terms as justification for the price hike. While it may not be the biggest jump, that extra $500 to $1,000 could be money in your pocket or go toward other costs like venting and piping.
Is a Stainless Steel Heat Exchanger Right for You?
We touched on the pros and cons of stainless steel water heaters to give you some insight into what the big deal is with the latest and greatest in tankless water heater technology. From here, you’ll be able to make a more informed decision while you shop around for the right tankless water heater for your home.
We’ve been around the block about a thousand times, and one thing we can say is that stainless steel heat exchangers are a viable upgrade when it comes to tankless water heaters. While they may not be the ideal choice for every homeowner for a variety of reasons, they still present a certain level of value that is rare to come by in any home appliance.
Whether you’re looking for a stainless steel or copper heat exchanger, give us a call at (310) 853- 8690 to schedule a consultation. You can also visit us online at our Tankless Water Heater Page to learn more about our services or book an appointment there instead.
Before you call in, it’s also worth getting a handle on how much a tankless water heater costs and how certain brands like Navien and Noritz stack up. If you need a more direct comparison, get up to speed on the differences between popular brands Rheem and Noritz.
