Photocalytic Air Purifier: Sun Pure

Photocatalytic air purifier details will take you directly to the PCO page. A quick summary; PCO is a technology of the future, with great potential and a few unanswered questions. I like it, but have waited to buy and test a PCO air cleaner. At $1000, I will keep waiting.

The Sunpure SP-20C has a Titanium Dioxide PCO grid, activated by ultraviolet light (UV). The company claims that this air purifier converts a long list of toxic volatile organic compounds, even carbon monoxide and nitrous oxide, to carbon dioxide and water. Solvents, hair spray, tobacco smoke, and ozone are on the list. (All these should be manually removed from your airspace, rather than relying on an air purifier.)

These results have been verified by outside labs. Microorganisms, including viruses so small no filter could retain them, are claimed to be inactivated. The efficiency of the PCO process is unimpaired by time, nothing wears out except the UV light.

If all this is true, we have a breakthrough. So why does the company rely on deliberately vague marketing tactics, which cast a shadow of doubt on their sunshine machine?

A single low-pressure 8 watt UV mercury lamp, stashed safely inside the chamber, provides germicidal UV dosage at 32 microwatts per second/cm2 (30 per Clarifier's engineer). This is average power as a germicidal UV air purifier, and Ultra Pure has declined to offer data on the specific frequencies emitted.

PCO generally uses a broader band of frequencies than the focused 254 nm best suited for germicidal applications. Many cheaper UV air purifying devices use poorly focused frequencies, but they start in the low $100's.

Sun Pure Ozone and Negative Ions?

The company's video asserts that the Sun Pure air purifier is ozone free, but the ozone synonym "activated oxygen" is used also. Like everything else about this air purifier, hard data is missing on the ozone issue.

References are also made to negative ions created by the UV light. This is a new one on me. Again there are no ion density figures, but I expect the numbers would be small. This looks like an attempt to jump on the ionic air purifiers bandwagon without actually including a negative ionizer.

SunPure is Automated

This might just be the most fully automated room air cleaner I have seen. I love microprocessor based computerized controls, and this purifier has them. 4 modes of operation and 7 room sizes allow 28 different power settings. Chemical and particulate sensors control airflow and alert the user to airborne contaminant levels via red, yellow, and green LED displays.

This will be a must for air purification equipment in the future: why pay to clean air which is already pure? Air purifier maintenance and operational costs can be much lower if the machine can adjust itself to impurities in the air automatically.

Without the assurance that air quality is acceptable, we cannot tell when it is safe to turn down a loud air purification device.

Sun pure has also added a unique automation feature. Infrared motion detectors turn down the power when there is less movement in the room. Since much particulate becomes airborne as a result of foot traffic or drafts, turning the airspeed down in an empty room seems desirable. However, this feature conflicts with the noise snowball problem I discusss in Quiet Air Purifier.

When a room is inhabited, the air purifier will get louder, causing the TV to get turned up, the kids to play louder..... Of course, users can manually adjust the speed anytime they like.

The filter monitor is not a pressure sensor, but a timer as found on cheaper air cleaners. The company's silence on actual sound levels forces us to rely again on the Clarifier engineer, who measured a Sun Pure at 68d(B)A@225cfm on high, and 58d(B)A on low. Pretty loud on low. For comparison, good bedroom noise levels are below 35d(B)A.

Maintenance and Warranty

Maintenance costs are low with annual replacement of the ultraviolet lamp and the filter every other year. This yields about $50 to $70 in yearly maintenance, very frugal. Sunpure has the lowest filter cost to original purchase price ratio of any air cleaning device I have seen. This will offset a portion of the steep initial purchase price over the life of the air purifier.

The company, headquartered in Corona, California, is called Ultra-Sun Technologies. Ultra Sun's president, Robin Scott, is active in the air purification engineering industry, a promoter of this exciting PCO technology.

The motor has double sealed ball bearings claimed to have a design life of 15 years, but is warranted for only 2 years. Too short for a machine that costs more than IQAirs and Blueairs, which are guaranteed much longer.

Measuring 21.5" wide by 18.9" high and 8.0"deep, the Sun Pure air purifier weighs 23 pounds. This is light and compact enough to be moved up and down stairs.

Conclusions: Sun Pure SP-20C

Ultra-Sun has put out a good effort, packaging PCO in a compact, attractive, air purification package. However, the price is out of reach of most consumers, and less expensive PCO is available. I suggest the company target upscale customers with high-road marketing strategies such as are used by IQAir, Blueair, NQ Clarifier, and others in the premium allergy-shop air purification market.

These companies publish elaborate technical data to substantiate claims and never use "activated oxygen" type terminology. Customers should not have to search dealer (in this case a competing builder) websites to find hard data on airflow, noise, and other details.

Air purifier consumers in the over $700 per room category will not be fooled by sunshine marketing flair.

Despite the above, I rate the Sun Pure a respectable 81, above many.

Air-Purifier-Power Rating Criteria

Each of ten factors gets up to 10 points, 100 is perfect and very unlikely.

1. First do no harm; minimal out gassing, no ozone.

Score: 8 of 10, ambiguous on ozone issue, slight odors are reported with new filters.

2. Serious gas and odor removal is a requirement if health benefits are expected: Units with real carbon VOC capability rank higher.

Score: 10 of 10, even if claims are inflated, PCO actively gets after chemicals/odors.

3. Quality construction; case, gaskets, seals, and precision fitting eliminate bypassing and assure high efficiency at filtering sub-micron particles.

Score: 7 of 10, design too loose for price.

4. The design maximizes the lifespan of each filter stage by allowing independent filter replacement. Ideally this is combined with electronic filter monitoring.

Score: 10 of 10,

5. Air cleaner has long filter life, low maintenance requirements and operating costs.

Score: 10 of 10, as cheap to maintain as many non-UV purifiers.

6. Purifier produces low noise levels and meaningful air flow rates relative to noise.

Score: 6 of 10, a bit loud, based on the limited data available.

7. Manufacturer has a track record, with many units in the field and a reputation for supporting what they sell. Warranty period and average service life are long.

Score: 7 of 10, low market penetration, 2-year warranty short for premium price range.

8. Purifier is a value in terms of price/performance ratio. Every price range should be included, “models above $1,200 are best”, while true, is not useful to most consumers.

Score: 5 of 10, very high priced.

9. No dirt; unit and manufacturer should be devoid of class-action suits, high returns, recalls, consumer complaints, and legitimate negative consumer reviews.

Score: 8 of 10, low information but no dirt on Ultra-Pure.

10. Unit is stylish, portable, comfortable, and convenient for consumer use.

Score: 10 of 10, no remote, beautiful automated interface.

Air-Purifier-Power Numeric Rating; 81, respectable

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