Medium-pressure UV (MPUV) has been a common choice for chloramine control in indoor commercial pools since the 1990s, but it carries a high cost of ownership. When you compare AOP vs UV, Clear Comfort’s Advanced Oxidation Process (AOP) controls chloramines at about half the purchase price, installs in about an hour with no added plumbing, uses 90% less electricity, and reduces chemical consumption by 30%-50%. UV, by contrast, can increase chlorine use by 20%.
Sustainability is a focus for industries throughout the economy. Businesses want to reduce costs while continuing to improve their processes, and with inflation raising the cost of energy, chemicals and labor, aquatic facility operators are taking a closer look at operating expenses. This guide breaks down the full cost of owning medium-pressure UV, explains how AOP works, and compares the two side by side so you can decide what fits your facility.
What Are Chloramines, and Why Do Indoor Pools Use UV?
Chloramines, also known as combined chlorine, are the main irritant to swimmers’ skin, eyes and lungs. The “chlorine smell” at an indoor pool, along with corrosion of the HVAC system, dehumidifier and anything made of metal, comes from volatile organic compounds (VOCs) that off-gas from the pool.
Commercial pools, especially indoor pools, often rely on medium-pressure ultraviolet (MPUV) to keep chloramines under control. MPUV was first used for chloramine control in Europe and arrived in North America in the 1990s, where it quickly proved effective. A large percentage of indoor pools use, or have used, MPUV. Most facilities that no longer run UV stopped because of its high cost of ownership.
What Does Medium-Pressure UV Cost to Own?
The cost of owning MPUV comes from four places: purchase and installation, electricity, added chemical consumption, and annual maintenance.
Purchase and Installation
Buying and installing a UV pool system can cost $30,000 to $80,000 for small to large pools. Installation requires a 100% bypass (three valves, two tees and two elbows), and two technicians for two days is a reasonable labor estimate. UV also requires three-phase electrical power and a high-amperage circuit breaker. Filter rooms rarely have space to spare, so the footprint of the UV bypass adds to the cost of new construction or takes up critical space in an existing facility.
Electricity
MPUV is electrically inefficient. Less than 20% of the energy it consumes is emitted in the UVC range (100nm-280nm), the wavelengths used to break down chloramines. Each UV system costs $2,000 to $12,000 a year in electricity, depending on pool size.
Chemical Consumption
UV degrades chlorine, which is the same reason outdoor pools use cyanuric acid to protect chlorine from the sun. Chlorine use can increase 20% after adding MPUV, and more powerful systems (above 100 mJ/cm²) can increase chemical consumption even more.
Annual Maintenance
MPUV has numerous points of annual inspection and repair. A typical service includes:
- Closing the three bypass valves and draining the UV bypass.
- Disassembling the UV chamber and removing the quartz lamps, which contain mercury.
- Removing the hollow quartz sleeves, which isolate the lamps from the water, and cleaning them by hand.
- Replacing the wiper O-ring and inspecting the automatic internal wiper carriage assembly (picture a windshield wiper without the wiper fluid), then replacing any worn parts.
- Inspecting all of the chamber’s O-rings and replacing them as needed.
Those are the major service points, and there are more. A set of lamps can cost $1,000-$2,000 or more, and quartz sleeves run hundreds of dollars each. Quartz blocks more light and becomes more brittle over time, so sleeves should be replaced every 2-3 years. Labor is typically outsourced to a certified technician at a few hundred dollars an hour, and each UV system needs 3-4 hours.
How Should Old UV Lamps Be Disposed Of?
Expired UV lamps contain a significant amount of mercury and should be disposed of legally, not dumped in the regular trash. The safe approach is to treat old mercury lamps as hazardous universal waste and recycle them through a qualified lamp recycler. The EPA’s universal waste rules cover mercury vapor lamps, and many states add their own requirements, so check your state’s rules before disposing of lamps.
What Is AOP (Advanced Oxidation Process)?
AOP uses hydroxyl radicals (•OH) to oxidize organics and the unhealthy by-products of chlorination, and it is also a proven secondary sanitizer. In pools, AOP oxidizes organics before they can form chloramines and destroys the chloramines that do form. The result is 30%-50% less chemical consumption and a much better swimming experience.
Hydroxyl radicals are the most prevalent oxidizer in our atmosphere, and there are billions of them around you when you’re outside. They are a more powerful oxidizer than ozone (O3), but they aren’t harmful to humans the way ozone is, because they react a million times faster, essentially instantly.
Where Did Clear Comfort AOP Come From?
Clear Comfort AOP is a supplemental technology originally developed to address Legionella bacteria in hospital cooling towers. The U.S. Department of Energy studied seven alternative water treatment (AWT) technologies for cooling tower water, and Clear Comfort’s AOP technology performed best. The final report, published under Clear Comfort’s former name, Silver Bullet, concluded:
“This AWT technology met all the predetermined success criteria for water savings, reduction in chemical costs, water chemistry, cost-effectiveness & ease of installation at the test location.”
“The AOP system needed no regular maintenance or monitoring.”
“Biofilm was seen before the installation of AOP but not after.”
“The hydroxyl radicals and other oxidants help to oxidize minerals and contaminants, killing bacteria, reducing biofilm, and inhibiting scale and corrosion.”
AOP vs UV: How Do They Compare?
Compared with medium-pressure UV, AOP costs about half as much to buy and 90%-95% less to install, uses 90% less electricity, and reduces chemical use by 30%-50% instead of increasing it.
| Medium-Pressure UV | Clear Comfort AOP | |
| Purchase and installation | $30,000 to $80,000 for small to large pools | About half the purchase price and 90%-95% less installation cost |
| Installation | 100% bypass, two technicians for about two days, three-phase power | About one hour of labor, no additional plumbing |
| Annual electricity | $2,000 to $12,000 per system | 90% less (about 1/10th the electricity) |
| Chemical use | Chlorine use can increase 20% | 30%-50% fewer chemicals consumed |
| Chloramine control | Frees the organic, which can form a chloramine again | Destroys organics and chloramines |
| Annual service labor | 3-4 hours, typically outsourced | Minutes of simplified labor by onsite staff |
| Cabinet weight | Smaller cabinets weigh hundreds of pounds | 95 lbs maximum for the largest cabinet |
Here’s how AOP and medium-pressure UV compare on cost, maintenance and water quality:
- Purchase price. AOP costs about half as much as UV, which needs heavy, expensive electronics to draw thousands of watts.
- Installation. UV requires a 100% bypass and about two days of work, while AOP installs in about an hour with no added plumbing, for 90%-95% lower installation costs.
- Electricity. AOP uses about 90% less electricity than UV, which can save thousands of dollars a year and may qualify for utility rebates.
- Chemical use. UV degrades chlorine and can raise chemical use, while AOP reduces it by 30%-50%.
- How organics are treated. UV separates organics from chloramines so they can re-form later, while AOP oxidizes them completely.
- Annual maintenance. UV service takes 3-4 hours and is usually outsourced, while AOP needs a few minutes from onsite staff.
- TDS buildup. Using fewer chemicals slows the rise in total dissolved solids, which saves water at facilities that drain and refill for high TDS.
- pH and LSI. AOP keeps pH and LSI more stable, so there are fewer water quality issues to manage.
- Disinfection by-products. AOP reduces unhealthy chlorine by-products beyond chloramines, as shown in the YMCA DBP reduction case study.
- Water and air quality. AOP improves water clarity, feel and air quality for patrons and staff.
Can You Get a Rebate for Switching from UV to AOP?
Often, yes. Because AOP uses 90% less electricity than MPUV, many electricity providers offer custom rebates for switching to Clear Comfort. We can help you find out whether a program exists in your area, determine the rebate amount, and supply the calculations needed for the application. Keep in mind:
- Many rebates require approval before the switch is made.
- The application takes about an hour to fill out and submit, and approval may take a few weeks.
- Once approved, the work usually has to be completed within a few months, often six (programs vary).
Can AOP and UV Work Together?
Yes. If you want to keep your UV system, adding AOP helps it perform better in two ways.
AOP Improves UV Transmittance (UVT)
AOP improves the UVT, or transmittance, of the water, so UV light penetrates better and works more effectively. UVT has a dramatic effect on UV performance. Compared with ultra-clean deionized water (100% UVT):
- 90% UVT reduces UV penetration by 36%.
- 80% UVT reduces UV penetration by 57%.
- 70% UVT reduces UV penetration by 69%.
UV standards in our industry assume a UVT of 94%. Pools, spas and splash pads with high levels of organics or turbidity likely have a UVT well below that. You can test UVT easily with a handheld spectrophotometer.
AOP Reduces Quartz Sleeve Fouling
AOP reduces the organics and metals responsible for fouling on the surface of UV quartz sleeves. Calcium carbonate, iron and manganese, aeration, UV’s high lamp temperature, and scratches from automatic wipers on the sleeve surface all increase the rate of fouling, as research on UV sleeve fouling has shown. Fouling increasingly blocks UV light from reaching the water. When these conditions are present, fouling happens fast, and the light reaching the water drops within weeks instead of months.
What If Your UV System Is Broken?
If your UV system needs costly repairs, it’s a good time to try AOP. Clear Comfort offers a 90-day money-back guarantee: if AOP doesn’t outperform your UV, you can get your money back and fix the UV.
Which Facilities Have Switched from UV to AOP?
Clear Comfort has ten commercial video testimonials from facilities that have used, or use, both UV and AOP, available on YouTube and on our website. Our Google reviews detail our technical support, timely customer service and exceptional water quality. Here are two facilities that switched from UV:
- Aquatics Facility Story: Dan, City of Tempe
- Aquatics Facility Story: Josh, City of Albuquerque, which switched 2,500,000 gallons across eight pools from UV to AOP
Frequently Asked Questions About AOP vs UV
Is AOP Better Than UV for Chloramine Control?
For most indoor commercial pools, AOP controls chloramines at a lower total cost. It destroys organics and chloramines, where UV only frees the organic from the chloramine, and it uses 90% less electricity while reducing chemical use by 30%-50%.
Does UV Increase Chlorine Use?
Yes. UV degrades chlorine, and chlorine use can increase 20% after adding MPUV. Systems above 100 mJ/cm² can increase consumption even more.
How Long Does AOP Take to Install?
About one hour of labor, with no additional plumbing and no 100% bypass. A typical MPUV installation takes two technicians about two days.
How Much Does It Cost to Run Medium-Pressure UV?
Each MPUV system costs $2,000 to $12,000 a year in electricity, depending on pool size, plus 3-4 hours of outsourced service labor and replacement lamps and sleeves. AOP uses about 1/10th the electricity.
Can I Keep My UV System and Add AOP?
Yes. AOP improves UV transmittance and reduces quartz sleeve fouling, which helps an existing UV system perform better.
See If AOP Is Right for Your Facility
Clear Comfort AOP is an effective, affordable way to control chloramines. UV comes with higher costs and limits on what it can do for water chemistry, while AOP, as an oxidizer, improves water chemistry in ways UV can’t.
We’re happy to walk your team through a quick but comprehensive webinar review: 25 minutes followed by Q&A. We can also help you apply for a custom rebate to switch from MPUV to AOP. Contact us to schedule a meeting, and feel free to reach out with any comments or questions.
Tom Schaefer
Technical Sales Director
