Kirby Vacuum Dirt Meter Pad Myths 

Already there are propaganda videos desperately attempting to refute the basic high-school-level science shown here that exposes the weaknesses of poor machines out there. Look out for dodgy propaganda sources that pack in three dirt meter pads instead of 1, artificially blocking the dirt meter and reducing the Kirby's already paltry suction, and making its performance even worse. That's also stupid because it implies they think Kirby should be making their pads three times thicker, and that these people don't seem to understand how these pads work. They're supposd to be porous to allow air through with minimum resistance, but also net particles. Even if you used 1 pad like any sensible person would and as I myself used, using only sand, as is often seen, is absurd and unrepresentative of natural household dust. Nothing in these propaganda videos actually directly explains any of the empirical observations and measurements made under the honest conditions I tested-they evade that responsibility because you can't argue against facts. Look out for the deceivers who peddle nonsense and don't like when these facts expose the weaknesses of inferior products and design. It's a tribalistic reaction.

Using ohms law, a formula for direct current electricity, as a parallel for fluid dynamics is barbaric at best.

So why does a Kirby leave the wood floor under my carpet clean, while everything else leaves a ton of dust under the carpet?

I agree with what you're saying but if the airflow is so much higher to begin with, the question is how much does the resistance drop the airflow? It could be that it still has more airflow at the cleaner head

But the best vacuum is the vacuum that gets used… so if the enthusiastic peeps use it everyday…

I know for a fact that when the dirt meter is on and the zip brush is on the zip brush, it only runs half the speed

I'd like to get with you and develop a more accurate air flow testing method that's repeatable. As a mechanical engineer who designs industrial systems including fans, compressors, and pumps, it always bothers me how the Kirby fans love to state air flow, but they only test airflow at a single point; that is open head unrestricted air flow. What I'd like to see is a curve produced just like you'd buy any fan, compressor or pump. When you buy one of those pieces of equipment, you buy them based on the pressure (head) vs flow. In the case of a vacuum cleaner, it would be vacuum/lift vs flow. you NEVER buy a fan or pump based on run-out (unloaded), since that's not the operating condition. In doing so would give you flow at the operating point. I've see the Kirby fans say, "130 cfm air flow", but then see it only has 25 inches W.C. of lift. That results in a super flat curve with not much slope to it. What that means is small changes in suction restriction results in wild swings in airflow. We system engineers specifically avoid selecting equipment with low slope curves, as it makes the system difficult to control and guarantee performance. Case in point, a Kirby has 130 cfm at the head unloaded, but that number falls to 70 with a hose attached. Just the restriction of an open hose almost cut the cfm in half. That puts the Dyson with greater airflow at the hose than the Kirby. Dysons have a lower open unrestricted airflow, but they are able to generate about 110 inches W.C. of suction. That results in a nice, steep usable curve where changes in flow restriction do not result in drastic changes in flow. At only about 10 inches W.C. of suction the Dyson curve intersects the Kirby curve and anything above about 10 inches W.C., the Dyson has more airflow. I'd like to do 2 tests: 1) Make a test box with an air valve so we could test at varying amounts of restriction to generate an suction lift vs flow curve. We test open flow, then start closing the valve down incrementally to gather data all the way up to completely shut off (no air flow). With this data, you can overlay the curves of different machines to see where suction and flow intersect to tell the tale of performance. 2) Drill and tap a test port in the cleaner head to measure suction while in use. We could easily 3D print a test tube with port to install between the head and wand, but the Kirby aluminum head would need drilled and tapped. With suction pressure only, you can determine airflow from the previous test above. Do hard floors, low pile carpet, medium pile carpet, and shag. Measure the suction pressure in the head for actual airflow during use. Again, compare that to one another for performance. It will really tell the tale of performance of airflow in actual use, where the Kirby's airflow drops like a stone with increased suction pressure.

You didn't test the kirby bag against the dirt meter

This is actually the reverse of what I thought, I came here thinking the dirt meter improved performance than the normal bag being that its used to doop people in thinking their house is dirty.

I have a Kirby, bought it used because no sane person would buy a new one. I also have the Dyson V10. The only time the Kirby gets use is if there is a spill of something and the Dyson's filter is drying out after being rinsed.

All you mid level vacuum sales people are the same. Spray wd40 in an old kirby bearing when one comes in your shop, then sell the customer a sebo or something when they come back in 6 months

Great factual video as always👍, my grandparents sent me a 1980s kirby. It stinks to all mighty and is in pretty poor shape. Sad in a closet filled with stinky dog dirt for 20+ years🤢🤮, it needs about $300 of repairs, which I'm unwilling to 💵 in 🗑 for it.