Dust Sensors Found Lacking

A frequent contributor wrote;

Yesterday I went over to what is likely the best air and water purification store in Toronto (Elma Water).

We pulled out the .3 micron particle tester and found an ambient level of 350000 particles. We then tested 3 units at the air output: IQAir HPplus = 0, Winix 9000 = 15000, sharp fpp60cx = 12500 ).

Seeing that the Winix and the Sharp were comparable in terms of cleaning efficiency of ultrafines, I then moved on to test the Winix dust sensor: at what ambient dust level would the unit be turning on purification in auto mode?

I wanted to answer the question as to how useful the dust sensors really are.

We turned on the Winix at an ambient 350000 pm .3 level in auto mode and it registered a dust level that put it in its lowest auto setting (green). the machine ran for about 5 minutes.

When the ambient level went down to about 250000 it turned itself off.

Well this was the end of my imaginary deference to dust sensors: if other companies have similar norms set for auto-mode then it is useless: it seems to me that 250000 ultrafine particulates as a norm is far too high.

I am now satisfied that my sharp unit put on high or medium during my time at home is the ONLY WAY to ensure clean air.

I don’t imagine that the sharp sensitivity switches bring the maximum dust levels for auto mode down that much either.

In any case, my whining over the Sharp Plasmacluster fpp series' seemingly insane absence of a dust sensor is over.

I wonder what the Rabbit Air's and Sharp's maximum dust level's in auto mode are.

If they are similarly poor you may have to retract your webpage's statement: "This group is gaining market share, and my admiration, as time goes by. Automated, sensor driven air cleaners are the way of the future."

Ed's Reply

Hey Contributor;

Outstanding field work, Dude!

You have discovered a secret, part of the reason so many builders are leaving a sensor or two off in the downturn of 2009.

Good particle counters cost big bucks, starting around $USD 2k. And even there you get .3 micron and up sensitivity.

IQAir has informed me that to add a sensor commensurate with their product quality would price the product beyond reach.

Machines selling in the low $100's have shipped with dust sensors - obviously these are very cheap. Some Panasonic, Hamilton Beach, and Neoair models come to mind.

Odor sensors, which can sniff subtle scents and activate the machine, are a better marketing twist.

Despite the disappointment from Winix 9000, and suspicion cast on competitors, I stand by my statement.

First, that Asian builders are gaining market share is not in dispute.

Second, sensors will come down in price as performance improves and production numbers rise. Economies of scale will kick in.

The recent addition of an entire product line by top engineering competitor BlueAir, the Blueair E-series, indicates this process is slowly happening.

The automated BlueAirs carry a $150 price premium over manually switched cousins. We will see how the premium segment reacts to Blueair's decision.

Thanks for the quality contribution,

Ed