Dyson DC25 Animal Airflow Losses

[wyaple]

The first two measurements were easy to get, the last one (CFM at the nozzle) required me to build an airflow box. I think this pic should easily illustrate where and by how much CFM is lost in this machine. I think this is typical performance from a cyclonic bag less cleaner.

From the base of the machine through the cyclones, there is a loss of 119-74 = 45 CFM. From the cyclones to the nozzle, there is a loss of 74-57 = 17 CFM.

Total airflow losses from the canister base to the power nozzle (held at a 45 degree angle to the floor) is 119-57 = 62 CFM or about 52% of the original airflow.

Last note: the rug plate opening is VERY small (about 17 square inches), but CFM density is well ABOVE average, about 3.4 CFM/Sq. In. If you ever wondered if this expensive 11 Amp beast was capable of deep cleaning, it certainly is. Airflow density (due to the small nozzle) is on par with the almighty Kirbys.

Bill

 

[kloveland]

It seems like it's losing a good percentage of it's airflow through that complex system of hoses. The Kirby Heritage and Hoover U4007 had better airflow and used less amps. 

 

[wyaple]

Absolutely,

Power usage wise, bag-less machines are the least efficient of the bunch. Most of the airflow gets "used up" in the cyclones.

The only reason the DC25 can deep clean so well is that Dyson realized that about 60 CFM was going to be about it for this design. By shrinking the nozzle size, voila', great CFM density was the result. You can actually hear a Kirby-like air whooshing when transitioning from carpet to bare floors. My DC14 doesn't do that because the airflow density is too low.

Bill

 

[tekjunkie28]

I still will never buy one of these plastic pieces of junk again. I gave one away when I bought the house. None of them can clean well or are well designed. My mom, who takes great care of her stuff, has been through 2 of these.

Thank you for doing the test though!!! Where can I get a cfm meter?

 

[wyaple]

Shae,

Can you tell me what models your Mother had? Also, what types of issues did you experience?

I now have a 2004 DC14 and a 2008 DC25. Both are in great shape and needed minimal parts. The DC14 works OK, but can't deep clean. The DC25 deep cleans VERY well as my tests now prove. From the hoards of negative comments on this website, I had surmised that Dysons were neither reliable nor good cleaners. So far, I have been pleasantly surprised at their reliability and performance, especially the newer ball model.

BUT, I am not the average vacuum cleaner user. I always clean the Dyson's seals and brush roll after each use and usually rinse/dry the filters every month. To show you how badly the DC25 was clogged with cat hair, please see the pic below. I'm sure the former owners threw it out because it lost airflow.

Bill

 

[wyaple]

I Use a GM8901 Anemometer

For my precision measurements and a Baird meter for quick readings. The GM8901 can be purchased on eBay for about $25 USD.

BTW, here's another ridiculous pic of the hair clogged filter.

Bill

 

[suckolux]

I enjoy some of their models, one was a daily driver for 5 years, never had anything break here.