There are two types of ion exchange water softeners available today: Upflow water softeners and downflow water softeners. In this guide, we’ll be highlighting the key differences between these softeners and helping you to decide which is best for you.
📖 TL; DR
Upflow water softeners send brine up through the resin tank, while downflow softeners flow from top to bottom. Upflow water softeners perform more efficiently than downflow softeners.
Let’s look at these water softeners in more detail.
Table of Contents
- 📤 What are Upflow Water Softeners?
- 📥 What are Downflow Water Softeners?
- 🆚 Upflow Vs Downflow Water Softener Systems: The Key Differences
- 📑 Pros and Cons of Upflow Vs Downflow Water Softeners
- 📌 Upflow and Downflow Water Softener Comparison
- 🧠 Upflow Vs Downflow Water Softener FAQs
- 🧑⚖️ Upflow Vs Downflow Water Softener: Our Verdict
📤 What are Upflow Water Softeners?
Upflow water softeners send brine up through the resin tank during regeneration. This allows for an even, complete regeneration of the resin bed because the brine solution comes into contact with the resin very quickly, when it is the most effective and at its strongest.
This upward flow of water through the tank also has a “lifting” effect and spreads out the resin bed, so salt from the brine tank can easily be distributed around the resin beads.
📥 What are Downflow Water Softeners?
Downflow water softeners look virtually the same as upflow softeners, and the softening process itself is identical. The big difference is the regeneration process: instead of being sent up through the bottom of the resin tank, the brine solution is pulled down through the top of the tank. Keep in mind that only the bottom two-thirds of the tank contains the resin.
When this happens, the brine solution is first diluted ever so slightly before it reaches the resin, which causes it to be less effective when it eventually reaches the resin bed. This also pushes the resin beads against the bottom of the tank, so salt can’t flow evenly through the entire bed.
During the softening process, a downflow softener sends water through an upper basket and down though the resin, finishing in a lower basket. The water, now fully softened, leaves the tank through a riser tube.
🆚 Upflow Vs Downflow Water Softener Systems: The Key Differences
The four key differences between upflow and downflow water softeners are:
- The direction of flow. Upflow water softeners push brine up through the bottom of the resin bed, so the brine water flows upward towards the top of the tank. Downflow water softeners, on the other hand, send water down through the top of the resin tank, so water flows down towards the bottom of the tank.
- The efficiency of regeneration. The upflow regeneration process is about 5% more efficient than a downflow system. What does this mean? You should be able to save money and salt by using an upflow water softener.
- The thoroughness of brining. Because upflow water softeners more effectively send brine across the entire surface of the resin bed, they offer a more thorough brining process than downflow water softeners.
- The system components. While most components in upflow and downflow systems are the same, an upflow water softener doesn’t need a backwash control valve, while a downflow softener does.
Proportional vs automatic brining. Upflow water softeners are ideal when they’re used for proportional brining – when a measured amount of salt is added based on how much of the resin bed needs to be regenerated. Downflow water softeners are more commonly associated with automatic brining.
📑 Pros and Cons of Upflow Vs Downflow Water Softeners
Now we know the main differences between upflow and downflow water softener systems, let’s look at the pros and cons of each softener type.
👍 Upflow Water Softener Pros
Why is an upflow water softener the best type of water softener to buy? We’ve explained what you need to know in the list below.
More Effective Softening
The design of upflow water softeners causes the resin to swirl in the tank. This allows for a longer contact time between the resin and the hard water, improving the effectiveness of the softening process and producing thoroughly soft water.
Channeling occurs when tunnels or channels are created in the resin, causing inefficient regeneration. Upflow water softeners send water through the resin in a way that fluffs up the beads, preventing the resin from becoming compacted and channels from forming.
Reduced Brine Usage
Upflow water softeners use up to 30% less brine than downflow softeners for regeneration. Less brine used = less brine needed, so you can save money on salt and reduce your maintenance as much as possible.
Low-Cost to Run
Finally, upflow water softeners don’t use electricity to operate, so they’re a low-cost softening system type to run.
👎 Upflow Water Softener Cons
Although upflow water softener systems certainly have more perks than setbacks, there are still a few negative aspects of owning one of these systems.
More Complex Systems
There’s more complicated liquid engineering that goes into the design of an upflow water softener. This can often mean that the system is more likely to develop faults than a more basically-designed downflow softener.
Regeneration Can Take Longer
We don’t want to generalize, here, so this isn’t necessarily a negative trait associated with all upflow water softeners. However, because water has a longer contact time with the resin bed, this could add a couple of minutes to the regeneration process.
Higher Price Point
From our research, we know that upflow water softeners aren’t extortionately expensive. However, they are, on average, more expensive than downflow water softeners. If your budget is tight, those extra pennies could add up.
👍 Downflow Water Softener Pros
Some of the positive aspects of a downflow water softener are:
Downflow water softeners have a simple, easy-to-understand design, and are easier to configure than upflow water softeners. Replacing the parts for this type of system is likely to be easier.
Again, not to generalize too much, but downflow water softener systems are typically more affordable than upflow softeners. Does this mean they’re a better value? No – but they are more appealing to people with smaller budgets.
👎 Downflow Water Softener Cons
The biggest downsides of using a downflow system are:
The brine dilution experienced during the downflow regeneration process causes up to 18% of the brine solution to be lost. This means that the softeners are less efficient than upflow systems.
Downflow water softener systems end up leaking salt down the drain. This sodium discharge has potentially negative environmental implications. Plus, downflow systems use more salt, water, and energy, so they’re not as green as upflow softeners.
Entire Resin Regeneration Required
When the hardness minerals are washed out of the resin in a downflow system, they’re washed through the entire resin bed. The result is that the full bed needs to be regenerated.
Compacted Resin & Less Effective Softening
The way that water flows in a downflow water softener causes the resin bed to become compacted. As a result, the resin can’t be fully utilized during the softening process, resulting in poorer soft water production.
📌 Upflow and Downflow Water Softener Comparison
In this section, we’ve compared downflow and up flow water softeners across three important areas: softening process, cost, and lifespan.
Both downflow and up flow water softener systems use the ion exchange process to produce soft water. This exchanges calcium and magnesium hardness ions for equal amounts sodium ions, effectively, softening water. The only difference in the performance of these systems is the direction of the brine flow (from the brine tank into the resin or mineral tank).
An upflow system has a water flow upward, from the bottom to the top of the tank, while a downflow water softener sends brine water down through the resin beads, from the top to the bottom of the tank.
The initial cost of an upflow water softener system is typically $700-$2,000. Our research has found that the sweet spot for this type of water softener is $1,000-$1,500. Pay any less, and you risk buying a poor-quality system. Pay any more, and you’re not getting the best value for your money
Downflow softeners are slightly more affordable than upflow softeners, starting at $600 and reaching up to $1,500. We’d recommend paying at least $800 for this type of system. Don’t pay any more than $1,500 – if you have this money to spend, you may as well buy an upflow system.
Why are both systems so pricey? A whole house water softener is a big unit, with a long lifespan. Although the initial cost is high, a water softener pays for itself in a matter of years.
The running costs associated with water softeners are for salt, water, and electricity usage.
Most upflow water softeners work without electricity, and their efficient softening and regeneration process means that they don’t waste as much salt and water as a downflow softener. There’s less ion leakage, so you can top up the salt tank less frequently. The average annual running cost of an upflow softener is $72-$110.
Downflow softener systems are less efficient and waste more salt and water than upflow softeners during regeneration. Some of these systems also use electricity, and you’ll need to top up the salt more frequently. The average annual running cost of a downflow softener is $120-$150.
Running costs aren’t only dictated by the type of softener. They also depend on the brand and quality of the salt you use, and whether maintenance or servicing is required, so your own running costs might be higher or lower than these averages.
Both downflow and upflow water softener systems have a lifespan of between 10 and 20 years, depending on component quality and resin crosslink percentage. The resin may last slightly longer in an efficient upflow water softener that only regenerates the portion of resin that has been used.
To get continued access to soft water, you’ll eventually need to replace the resin, or the entire system itself.
🧠 Upflow Vs Downflow Water Softener FAQs
Which is better, downflow or upflow water softener?
An upflow water softener is best because it cleans the resin beads more evenly, when the brine solution is at its strongest.
What are the best upflow water softener brands?
Some of the best upflow water softener brands are SpringWell, SoftPro, Fleck, and AquaOx. One of Fleck’s water softeners, the 5600 SXT, even lets you choose between upflow and downflow performance. You can read our full review on the best upflow water softeners here.
How do you know if a water softener is upflow or downflow?
Check the product’s marketing materials. If it’s upflow, the manufacturer will likely tie this into increased efficiency and money-saving performance. But don’t just assume. If you don’t see the word “upflow”, check the product manual or contact the manufacturer to ask directly.
Which is cheaper: upflow or downflow water softeners?
Downflow water softeners are generally (although not always) more affordable than upflow softeners. However, you get a better value for money with upflow softeners because even if you spend a bit more upfront, you’ll save money on salt and water over the decade or so that the system is in use.
🧑⚖️ Upflow Vs Downflow Water Softener: Our Verdict
If you want to buy a water softener that offers the most efficient performance, an upflow water softener is your answer.
This type of water softener makes better use of salt and water during regeneration. This means that the softener will waste less of these resources, so you’ll save money and require fewer supplies throughout the year.
However, there isn’t a huge difference in efficiency between upflow and downflow water softeners. If you’ve got your eye on a downflow softener, don’t rule it out entirely. Just know that you may end up using a bit more salt and water per year with this type of softener.