Thread Number: 32963  /  Tag: Recent Vacuum Cleaners from past 20 years
Vacuum Efficiency
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Post# 360461   10/6/2016 at 12:43 (2,729 days old) by wyaple (Pickerington, OH)        

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Ever wondered about how efficient a vacuum is? For example, if a machine can produce 100 CFM at the nozzle (or hose) and uses 10 Amps, that would mean an efficiency of 100/10 or 10 CFM/Amp. How do clean air/dirty air/canister/uprights stack up against each other? Does newer mean better?

NOTE: these tests were performed without bags or filters. Adding fresh cloth bags/water/clean filters don't actually change the results by any significant amount if you were wondering.

From my tests, cyclonic (bagless) and water based machines are the least efficient and old technology dirty air machines are the most efficient. The bagless vacs tend to score around a 6-7, while clean air uprights tend to score around a 9-10. Things really get interesting when looking at dirty air uprights measuring in the 20-30 range.

My 1987 Kirby is the most efficient at 31.5 CFM per Amp used for a nozzle test and my 1997 G5 wins the hose test at 19.4 CFM per Amp.

What do you all think? Does efficiency matter? Should the EU refine their requirements to include efficiency? Maybe it would be like examining the miles per gallon when shopping for cars.

Bill



Post# 360480 , Reply# 1   10/6/2016 at 15:59 (2,729 days old) by sptyks (Skowhegan, Maine)        

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Bill, thank you for doing these tests. As someone who owns 5 Kirby's, I am very surprised at the huge difference between the nozzle tests of the Heritage II and the Sentria II.

 

This is puzzling  because the Sentria II not only has a larger motor, but also has a more streamlined mini emptor than the Heritage II. Another point is that I believe they both use the same fan. Any ideas on why there's such a large difference?

 

~Stan

 

 


Post# 360493 , Reply# 2   10/6/2016 at 17:57 (2,729 days old) by suckolux (Yuba City, CA)        

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Interesting test to see! I know my Kirby and Royal use half the amps sometimes and sure clean faster too! Time running comes into play as well

Post# 360494 , Reply# 3   10/6/2016 at 18:34 (2,729 days old) by wyaple (Pickerington, OH)        
Please remember that these are efficiency tests...

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not absolute value tests.

But thanks for the thumbs up, Stan! Sometimes, I wonder if anybody really cares about measurements rather than simply getting emotional about the vac they "love".

Anyway, with the same fan in the 1987 and 2012 Kirby, you may not be surprised that the airflow is very similar; however, the current they both use is quite different.

The 1987 Heritage II Legend only used 5.17 Amps, while the 2012 Sentria II used 7.46 Amps. These measurements were taken without bags, but under normal load (actually vacuuming medium pile carpet) conditions. That's more than a 2 Amp difference due to the Sentria II having a Tech Drive and a motor that spins a bit faster (higher RPM).

Which one cleans better? The Sentria II of course, but not by much although different brush rolls are available that the Heritage can't use.

Bill


Post# 360501 , Reply# 4   10/6/2016 at 19:43 (2,729 days old) by sptyks (Skowhegan, Maine)        

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Thanks Bill for the quick answer to my question.

 

Your answer makes perfect sense now that I think about it. I knew that the two machines in question had similar airflow but I was totally forgetting about the difference in current draw which is more than 2 amps. 

 

 


Post# 360524 , Reply# 5   10/7/2016 at 10:09 (2,729 days old) by dysonman1 (the county)        

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One of the differences in current draw between the Heritage II and the Sentria II is the fact the self propelled models have to drive the transmission, which put an additional drag on the motor, making it draw more amps.

Post# 360541 , Reply# 6   10/7/2016 at 20:34 (2,728 days old) by moderneezer (Gatineau, Quebec, Canada)        

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I think the EU should consider refining their requirements to include efficiency.

Also, I would like to know what the results would be like for the models that haven't been tested.

Maybe Tacony would design new models that might be more efficient than the Kirby's you tested.


Post# 360619 , Reply# 7   10/9/2016 at 19:23 (2,726 days old) by wyaple (Pickerington, OH)        
Moderneezer

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I'm not sure what you mean by...
"Also, I would like to know what the results would be like for the models that haven't been tested."
To me that means you'd like to see all other machines tested that weren't posted in my results. While I'd love to attempt to test all models, I image I'd be pretty tired after testing for a few years...

"Maybe Tacony would design new models that might be more efficient than the Kirby's you tested."
As my tests easily prove, dirty air machines are the most efficient by a long shot, so unless Tacony decides to make a dirty air model (and maybe they do?), Kirby wins this round.

What I haven't tested yet are battery operated vacs. When I get one, I'll be sure to post all possible results.

Bill



Post# 360644 , Reply# 8   10/10/2016 at 12:45 (2,725 days old) by moderneezer (Gatineau, Quebec, Canada)        

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It would be great if people designing vacuum cleaners could do efficiency tests on the models.

Oh and I didn't see that it was someone other than Dysonman1 who posted this thread.

I still think that vacuum cleaners should be efficient.


Post# 360670 , Reply# 9   10/10/2016 at 23:42 (2,725 days old) by Hutch (Waseca MN)        
efficiency tests

I'm new to the Forum and was just reading your subject material and found it interesting. Just to give you a bit of my background I'm a retired Soldier, I'm also retired off of the railroad as an engineer and I'm currently working building HVAC systems. It appears in the post when you're talking about CFM and the dirty filters or bags have no bearing on it I don't believe that is quite correct. Being as your measuring constant flow if you interrupt the flow with a dirty bag it is going to reduce the flow, we're not talking suction power were talking about air mass moving through a channel. To help put it in perspective I've done some tests myself. The first test that I do on vacuums is a test raw suction by putting a vacuum meter on it. Example Dyson DC41 will pull 28 kPa. Kirby Sentria will pull 14 kPa. Don't get upset with what I just said but keep in mind the Dyson does have double the amps of the Kirby so therefore it should be double the suction So Dyson's statement that the Dyson has twice the suction is correct however there's more to the equation. When you hook up a CFM meter you will find that the Dyson pulls about 50 to 80 CFM on my machine now it is not calibrated but by contrast when I hook up a Kirby Sentria it will pull 200 which tells you that it is got way more air mass moving through it also the Kirby allows you to adjust the head up and down which allows you to use more of the suction. And then I've done test to see which one actually picks up more dirt on the same pattern and path and every time the Kirby does a much better job. By the way I use a Dyson when I vacuum. Now it also holds true for the older Kirby's such as a classic 3 I have one of those and it also does very well it pulls about 120 to 130 CFM on my cfm machine. And just to make it perfectly clear when you're talking suction put your vacuum hose against your hand and let it totally bottom out that's what you're talking about with suction. So in that case yes a dirty filter or a bag makes absolutely no difference because the machine is going to bottom out at its maximum suction rate. If you find it hard to believe take a very small cloth bag and blow through it and it'll be very easy to blow through and I'll take that bag and soak it in water pull it out and blow through it you reduce the CFM. Maximum suction from what I found max kpa is not so important proof of this is when I tested my Ridgid 6.5 horsepower shop vac which has a kPa rating of 15 kPa yet has a CFM flow of 300 to 350 and quite frankly there's not an upright or canister thats going to keep up with it and I think we all know that, so the CFM flow rate is very important. And I also have to tell you I do agree 100% that for amps used the older Kirby's to include the newer Kirby's seem to perform far better then any of the newer Bagless vacuums. Well that's my two cents thanks. Hutch

Post# 360686 , Reply# 10   10/11/2016 at 11:51 (2,724 days old) by sptyks (Skowhegan, Maine)        

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Hutch,

Just to clear up any confusion. I believe Bill said that he performed all tests with no bags or filters installed in any of the machines. He also stated that installing brand new bags and filters did not make any significant difference in the test results. No dirty bags or filters were used in the tests.

 

I'm curious. If the Kirby's clean so much better than the Dyson, then why do you still vacuum with the Dyson?

 

 




This post was last edited 10/11/2016 at 12:30
Post# 360695 , Reply# 11   10/11/2016 at 13:29 (2,724 days old) by wyaple (Pickerington, OH)        
Thanks for you post, with tests!

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Hutch,

Welcome to VL and thanks for posting some of your tests! It’s great to see someone else make objective measurements. Since you have quite a bit packed into your “wall-o-text”, I’d like to break it down somewhat.

“It appears in the post when you're talking about CFM and the dirty filters or bags have no bearing on it I don't believe that is quite correct.”

I’m not sure what you mean by being not correct. My tests were measuring CFM with no bags or filters. When most manufactures publish a specification for airflow (or maximum airflow), this is where they would start. Many canister makers don’t even take into consideration hose/power nozzle tube losses or even motor losses when the motor is placed in the machine body. Take Aerus for example, they claim their top-o-the-line machine has a motor which produces over 505 Airwatts. That can be very misleading because Airwatts is technically a point cherry picked from a graph. It doesn’t easily reveal CFM or water lift to the consumer. As my other posts here on VL have revealed, CFM loss is much less than what you would expect with cloth HEPA bags as the pores usually never clog all that much in regular (non-abusive) use.

“The first test that I do on vacuums is a test raw suction by putting a vacuum meter on it. Example Dyson DC41 will pull 28 kPa. Kirby Sentria will pull 14 kPa. Don't get upset with what I just said but keep in mind the Dyson does have double the amps of the Kirby so therefore it should be double the suction So Dyson's statement that the Dyson has twice the suction is correct however there's more to the equation.”

I know that outside of the U.S., many companies including Dyson post water lift in kPa, but that unit is much more easily understood if converted to inches of water (especially if graphing Airwatts). The conversion rate is 4 inches of water per 1 kPa.

Your DC41 = 28 kPa = 112”
Your Kirby Sentria = 14 kPa = 56”

Claiming a doubling of suction just because the motor draw is double the amps is a completely false statement. That would mean that all motors are essentially of the same performance “slope” and all one would have to do to decide how much power your machine would consume and would be to simply pick an engine off the shelf in the desired power category. Based on what the manufacturer wants, the very same total power usage results in widely varying CFM and water lift capabilities. Remember, motors may have more than one fan and this obviously greatly affect the CFM/water lift curves.

Incidentally, my measurements for my DC14 are 112” at the hose and 120” at the base with or without filters. CFM maxed out at 79 CFM at the hose (no filters) and 75 CFM (with filters). I still think it’s funny that Dyson keeps pushing the “never loses suction” mantra when it’s airflow that matters more. And their vacs definitely lose airflow, even the newer ones without any filters.

“I've done test to see which one actually picks up more dirt on the same pattern and path and every time the Kirby does a much better job. By the way I use a Dyson when I vacuum.”

I’m confused. You’ve seen that a Kirby does a much better job than a Dyson, but you still use a Dyson as your daily driver? While I have only a small collection of vacs and use them all (why have them if you don’t use them), I always make to sure use my Kirbys periodically if not more regularly to get all the dirt possible.

Rigid 6.5 HP shop vac:

Yes, the airflow of that shop vac is tremendous, it could filter the air in a room vary quickly at 300+ CFM!

Do you realize that those HP ratings are completely false? They are literally measured in the first few milliseconds of motor turn on. Steady state power usage of that machine is 12 Amps. 12 Amps at 120 Volts = 1440 Watts = 1.93 HP or about 2 HP. This is approximately the same current usage as the high power 12 Amp rated Dysons. So for the same power usage a Dyson produces 80 CFM-ish and the rigid produces over 300 CFM-ish. Of course, the motors are used differently, but I hope you see my point. Manufacturers pick a motor based on how they want the machine to perform, not just on a power usage slope.

Just for laughs, consider this:

Rigid @ 325 CFM using a real 12 Amps would mean an efficiency rating of 325/12=27.1 CFM per Amp at the hose, which betters just about everything out there I can think of, except maybe another shop-vac.

“And I also have to tell you I do agree 100% that for amps used the older Kirby's to include the newer Kirby's seem to perform far better then any of the newer Bagless vacuums.”

Bagless systems (and water based systems) are very inefficient by design unfortunately. Much of the motor’s CFM is lost by creating dirt tornados and jamming dirt into water. If you measure your Dyson DC41 at the motor base, you’ll find it may produce something like 120-130 CFM. My DC14 produced 128 CFM at the base (before all those 8 cyclones).

I look forward to reading more of your posts that include tests.

Bill


Post# 360696 , Reply# 12   10/11/2016 at 13:55 (2,724 days old) by Hutch (Waseca MN)        
Why dyson

Sptyks, I'm glad you asked the reason being is as for most people I prefer the convenience of not having to deal with a bag. I'm also glad you brought up the point that he stated that he does not use bags when he's doing his test I can guarantee you this, it will definitely skew the results, a good example is when he states that the G5 does better than the sentria that makes sense because the Sentria has a smaller emptor however when you throw the bag on as I've done when I've tested them you'll find Sentria has a higher CFM rate then the G5 if they're both using the same bag ,if the G5 is using a non HEPA filter bag it will win as far as CFM flow rate but not in particulates that it takes out. The test also needs to be performed with the bags zipped up ,if all you have is a vacuum with no bags on it blowing in the breeze You're just testing to see whether or not it works well as a fan. Another point to look at is the fact that the outer bags are made of different materials.So the Sentria has got a smaller Micron that it will trap vs. The G5 which also means that it is more restrictive on air flow no matter how clean it is. One way you could get around that would be to increase the size of the bag thus increasing the surface area allowing more air flow. That's one of the reasons why they had to up the power of the Machine by what is it a half an amp? Don't take it as a personal attack they are still both excellent machines. I'm just trying to pass on some knowledge of how to properly rate CFM. You would not try to rate a Jacks lift capacity with no load would you? Tell you what tonight I will test a Sentria with the bag and without. My prediction is a 20-30% gain. Hutch

Post# 360704 , Reply# 13   10/11/2016 at 14:31 (2,724 days old) by wyaple (Pickerington, OH)        
Please post your Sentria results, Hutch

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Here's mine.

Kirby Sentria II (Measured@Body Low Fan Speed) = 6595 ft/min = 172 CFM = Baird 10.0+ <-- No Bag
Kirby Sentria II (Measured@Body Low Fan Speed) = 6555 ft/min = 171.1 CFM = Baird 10.0+ <-- HEPA Bag

Results: Negligible loss due to a clean cloth HEPA bag at the nozzle end.

Kirby Sentria II (Measured@Hose Low Fan Speed) = 4587 ft/min = 120 CFM = Baird 10.0+ <-- No Bag
Kirby Sentria II (Measured@Hose Low Fan Speed) = 4528 ft/min = 118.2 CFM = Baird 10.0+ <-- HEPA Bag

Results: Negligible loss due to a clean cloth HEPA bag at the hose end.

Bill





Post# 360708 , Reply# 14   10/11/2016 at 14:42 (2,724 days old) by wyaple (Pickerington, OH)        
As I have mentioned previously...

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The vacuum manufacturers normally rate things without loads applied in the production product. Take the fake HP ratings I just proved in the above post. And Aerus measures their motors and posts specs without it mounted in the machine at all!

BTW, I have literally BOATLOADS of tests measuring all kinds of aspects of vacuums. Just search VL for my username and see what you can dig up, you will be surprised.

BUT, I look forward to any tests you care to post, it's great to have someone else motivated enough to put up some numbers.

Bill


Post# 360715 , Reply# 15   10/11/2016 at 15:31 (2,724 days old) by Hutch (Waseca MN)        
Loads

Bill, when I say load I'm not referring to "the machine needs to be sitting over a pile of dirt" I'm simply stating that it needs to be in the exact configuration as it will hit the floor in which is with all bags attached and all hatches closed.
Hutch


Post# 360717 , Reply# 16   10/11/2016 at 16:02 (2,724 days old) by Hutch (Waseca MN)        
Results

Bill, okay here we go the test results. Kirby Sentria testing with the attachment hose hooked to the CFM machine ,bag attached HEPA bag installed. =115 CFM.
Now with the HEPA bag removed and the outer bag unzipped and the hose pulled out the back =138 CFM. And yes it is a Brand New Bag and the outer bag that's on the machine is a brand new clean bag. Keep in mind this is what I do for a living so I'm well aware of how the tests have to be conducted we have where I work a cfm machine that can detect a half CFM change on an 8 foot panel filter. When you conduct your test the machine literally must be clamped down to the test table the hose may not move in any direction whatsoever the only thing that you can open or close and remove is the bag .that's the only way you'll get an accurate reading. Hutch


Post# 360728 , Reply# 17   10/11/2016 at 18:13 (2,724 days old) by wyaple (Pickerington, OH)        
I retested my Sentria II and here's my results

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Tests performed with a freshly laundered bag and new (unused) Kirby cloth HEPA bag. Measurements were taken with the front nozzle removed, but with an adaptor affixed similar to the air intake guard and the motor running at its low speed.

From Nozzle, no inner bag, outer bag unzipped 6851 ft/min = 179 CFM
From Nozzle, no inner bag, outer bag zipped 6811 ft/min = 178 CFM
From Nozzle, inner bag, outer bag unzipped 6792 ft/min = 177 CFM
From Nozzle, inner bag, outer bag zipped 6792 ft/min = 177 CFM

Hutch,

I'm not entirely clear as to what you mean by "with the attachment hose hooked to the CFM machine". Is this the Kirby hose attached so the machine has been converted to run like a canister or is this a testing hose that hooks up to your testing machine? A picture of your testing rig might help to clear things up a bit. I've posted pics of my gear in previous posts. I am very suspicious of a 23 CFM loss with a brand new HEPA bag, that's a major loss in my book.

I'll repost my bag tests from another machine to prove a point:

Hoover Tempo Widepath (No Bag) = 4370 ft/min = 114 CFM
Hoover Tempo Widepath (Hoover Y) = 4291 ft/min = 112 CFM
Hoover Tempo Widepath (Crucial) = 4370 ft/min = 114 CFM

As you can see above, there was zero CFM loss from going from no bag (in a clean air Hoover) to a clean Crucial branded cloth HEPA bag. The fresh paper "Y" bag suffered a 2 CFM loss.

Come to think of it, your results almost seem like the motor may be running at different speeds?

Bill



Post# 360733 , Reply# 18   10/11/2016 at 19:52 (2,724 days old) by Hutch (Waseca MN)        
Results

Bill, I tested all using the attachment hose yes canister mode there is less variables in the seal. Simply putting your hand behind the output 6inches will change the air pressure enough to alter the cfm rate if it is set up correctly. And this mode will run at the highest speed.

Post# 360744 , Reply# 19   10/11/2016 at 21:34 (2,724 days old) by Hutch (Waseca MN)        
6.5 hp

Bill,also in response to your statement on the Rigid shop vac 100% correct. The manufacturer will use any number they think makes them look one up on the others after the same market. Prime example is Dyson's suction statement. Great if you are drawing blood from a steer but makes a small difference in the real world. Hutch

Post# 360745 , Reply# 20   10/11/2016 at 22:08 (2,724 days old) by Hutch (Waseca MN)        

Lastly, as my wife does most of the vacuuming the Dyson is the weapon of choice. However I do ones or twice a month use my 505 or my 512 but I enjoy the classic III best. I refer to it as my house Harley.

Post# 360876 , Reply# 21   10/13/2016 at 19:10 (2,722 days old) by Hutch (Waseca MN)        
General Question

Has anyone on this forum ever went in reverse? meaning that you converted a newer Kirby to a dirty bag set up? I've got a G3 not in use and being as the G3 and the sentria are pretty close in performance I think I'm going to give it a shot anybody have any suggestions what adapter would be needed if there is one for it. Hutch


Post# 360920 , Reply# 22   10/14/2016 at 16:54 (2,721 days old) by sptyks (Skowhegan, Maine)        
There is no way...

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that I know of to convert any G series Kirby to a shakeout bag system. I have never seen a shakeout bag conversion kit for any G series Kirby.

 

However there is a bagless conversion kit to make any G series Kirby into a bagless machine. It includes a plastic canister (Bin) with a filter inside that attaches to the Kirby exhaust port. You only need to remove the bag assembly and attach the canister-bin where the bag was, and you're done. 

 

I must warn you that this bagless conversion has gotten lousy reviews. It seems that the filter clogs quickly and must be cleaned after 30 minutes of use because performance diminishes quickly after that. It is also said that you need a second vacuum cleaner to clean the filter.

 

Here's the link:

 

 captainproducts.com/jrk-66-bagle...

 

Here's the link for Vacuumiand reviews:

 

www.vacuumland.org/cgi-bin/TD/TD-...

 

 

 

 


Post# 360928 , Reply# 23   10/14/2016 at 20:30 (2,721 days old) by Hutch (Waseca MN)        
Bagless

Thanks for the info. I did get a chance to see that some time ago and like you everything I've seen on it had very poor reviews so I really wasn't interested going that route. I do think that it probably would perform very well if it had a dirty bag system on it. I have a friend of mine who's got a nice milling machine maybe we can make a part that would make an adapter for it we'll see thanks again. If we do come up with anything worthwhile I'll post it here. Hutch


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