Air watts bagged vs bagless vacuums

[Mike81]

Have anyone noticed that bagged vacuums have more suction power compared to the bagless vacuums?
For example:
Bagless: Dyson DC39 280aw and DC54 300aw.
Bagged: Electrolux UltraOne 460aw and Miele S8330 380aw.
My daily vacuum (Bagless Electrolux UltraPerformer) has 330aw and my parents (my old vac) Philips PerformerPro 500aw.

My opinion is that 300aw is more than enough vacuum to have.
Opinions?

 

[sebo_fan]

Air watts should never be trusted. They are not measured properly in my experience and its a fad term that Dyson invented to promote his bagless vacs on the NLOS/No loss of suction claims.

The Air Watts may be higher than those listed with Dyson vacs but the bags do start to weaken suction and usually most brands indicate that the air watts has been measured using a fresh, new dust bag on board OR tested at the opening of the hose.

I once found an interesting video on You Tube explaining the truth behind Air watts. A lot of the info is true in the video though.

 

[Mike81]

Yes most bags lose suction, but there are some high quality fabric bags that can be filled almost full before suction decreases. Those bags are just quite expensive.
Excellent link and helpful!
Dyson is proven to have true no loss of suction cyclone technology.
I linked the video of vacuum cleaner measured (at the hose end) air watts. Tests was done by Finnish consumer reports.
Loss of suction was also measured and yes, Dyson didn't lose suction. But some bagged vacuums didn't either.

http://https//www.youtube.com/watch?v=W6xgQKYo1ro

 

[sensotronic]

I'm not sure if Dyson invented the term air watts as I have Hoover brochures dating from 1983 that specify the air watts of cleaners.

I seem to remember the first generations of Sensotronics had 250 air watts generated by a 1000 watt motor.

 

[Mike81]

250 aw is very good from the 1000w motor and more impressive from the 32 year old vacuum.
I have been reading those consumer reports tests and bagless models have less suction and more noise in every test where bagless and bagged are in the same test.

 

[oliveoiltinfoil]

Sebo bags, especially there latest ones which are much better made than previous ones, you can fill right to the top without any noticeable loss of suction power and those bags work out at around £1 each, or a box of 8 for around £9. Not expensive at all really.

Sebo seem to measure their suction power in litres of air per second, both the Felix and Felix eco rated exactly the same at 80 l/s.

 

[Mike81]

You are right. It's incredible how full you can fill quality bag without losing the suction.
My experience limits to the Electrolux S-Bags (Ultra Long Performance 5 liter). Also Philips uses S-Bags in their full size models. Those really can be filled almost full before suction starts to noticeably drop.
S-Bags cost around 3€ each. Not the cheapest, but one bag last roughly one month.

I have seen some information about litres per second, but I don't remember the figures.

I found this very informative video about differences between bagless and bagged vacuums.


http://https//www.youtube.com/watch?v=dSS-sZlEJdM

 

[sptyks]

Air Watts...

Are pretty much useless method of measuring vacuum cleaner performance.


 


The only reliable methods of measuring a vacuum cleaner's performance is airflow in Cubic feet/minute (CFM) or Liters/second and Inches of water for suction.


 


Air Watts are not accurate because the formula for calculation includes the wattage of the motor which can vary greatly in efficiency.  Example: a 1200 watt Dyson motor may be more or less efficient than a 1200 watt Sebo motor.

 

[Mike81]

Very interesting to hear.
I have seen some info about airflow liters/second and suction kpa. Not many manufacturers show those figures.
I found info about my past two vacuums

Philips PerformerPro: Airflow 51 l/s Vacuum 36 kPa
Electrolux UltraOne: Airflow 140 cfm Vacuum ??

Hard to say much about those. But now when EU has new standards vacuums have totally different rating system.
Sample picture shows how it's now.

 

[sebo_fan]

Air watts before Dyson? I stand corrected.

So, are Hoover to blame for misleading customers regarding air watts? Seems likely when the dust bag progressively clogs up and cuts the suction, despite most Sensotronic models feature variable power to compensate.

I have an Electrolx Excelio which uses an Electrolux S-Class bag as standard. Yes, it is highly efficient on filtration but I haven't noticed much of a diference between these bags and Miele's IntensiveClean or indeed the later HyClean bags.

Tne New EU labels aren't much help IMHO. Check other threads regarding the labels - they are always producing interesting discussions on here. I can't abide the new labels and don't agree with most of them featured on the vacuums I've bought so far this year that has come with the labels.

 

[Mike81]

I don't comment who first came up with the airwatts. For me airwatts has been some hint how powerfull the suction/airflow is. Other figures are usually not informed by the manufacturers.

These EU labels are misleading. For me those labels are useless what it comes to the cleaning performance. I will anyway use my Miele powerhead with my future canister vacs. So if I don't know anything but cleaning performance with standard nozzle. Well it makes choosing my future vacuums confusing.
So if I want to know how powerful the vacuum in the store actually is I have to take my turbo head with me, connect it to the vacuum and try to listen how fast it spins LOL.
My video shows how fast it spins with the 500 aw and 350 aw vac.

 

[Reflector]

Going by the first formula found here:
http://en.wikipedia.org/wiki/Airwatt
And a secondary formula which I found:
"(Air Flow (in CFM) x Vacuum (in inches of water lift))/8.5 = Air Watts"

A Sebo X4 has:
107CFM and 92.5" of water lift.

Which gives me 1120 airwatts, alternative formula gives 1123 airwatts.

A Sebo C3.1 has:
170CFM and 90.0" of water lift.

Which gives me a circuit breaker (To US standards) tripping 1795 airwatts, alternative formula gives me 1800 airwatts.

For reference:
The X4 has a 1300W motor that incurs a power penality for driving the brush assembly, the C3.1 has a 1250W motor with all the power going for suction.

Last time I checked, when I had my HEPA filter and clean, new synthetic bag in the X4 I had significantly more airflow going through the hose than my C3.1 with a paper bag and the well used S-class filter it has. I don't have a setup or gauge to measure water lift.

My airwatts must be some kind of imperial airwatts, given they're effectively double, triple or quadruple the numbers I see on the internet.

Oh wait, they're just full of phooey and I can't find flow or vacuum pressure specs. Instead I get something as worthless as seeing "5 (peak) horsepower" on a Shopvac, which implies it can pull 3.7kW through US wiring. At least they have the decency to include flow rates and "sealed pressure" (water lift) on their pages, next to "peak air watts."

 

[Mike81]

I guess those manufacturers ratings about cfm are misleading:
http://store.abcvacs.com/whatisairflow.html
"For instance a very popular canister the MIELE claims to have 140 cfm, WOW! but guess what that rating is taken before the motor is installed in the unit in an unrestricted environment, NO filters, NO bags, No 9 foot hose and wands, nothing. After restricted by the bag and filter and being 9 feet from the power source, The actual CFM of said unit as measured at the end of the hose is about 65 cfm"

For example Sebo D4: Airflow (motor rating) 120 CFM Water Lift (motor rating)95 in.
http://www.sebo.us/canister-vacuums/airbelt-d4/airbelt-d4-premium-best-canister-vacuum-cleaner.aspx

This is getting to be quite difficult to figure out real ratings.
Manufacturers ratings about air watts seems to be closest to the truth according to the Finnish Consumer Reports measurements.

 

[panofan]

airwatts

Reflector - there is a bit more to the calculation - airwatts is based on the CFM & suction (water lift) taken at the same time at the same orifice.

The ratings you typically see are max cfm and max lift - which are at opposite sides of the spectrum - e.g. max cfm is fully open at the motor at 2" where you typically have 0" lift. Full lift is sealed - 0" orifice - thus no cfm, but lots of inches of water.

Real power is in between. Eg. for a central vac motor, you can find the actual corresponding performance: http://dev.ametekfsm.com/Bulletins/116119-00.pdf

Keep in mind - even if you find the similar details for your own motor, you need to look at effective orifice -- i.e. let's say you managed to MacGyver this motor into your vacuum - and you had a 1.25" wand - you wouldn't see the performance at 1.25" - the filters, bag / cyclone, neck of the hose, the hose itself all add friction - your effective orifice would be at a smaller opening size.

 

[Mike81]

Lots of information thanks.
I have some knowledge about the airflow. If airpath is complex, small diameter, long and with sharp bends that is what kills it. Suction isn't so sensitive to those, but it also suffers.
For example bagless vacuum cleaner with complex cyclone system have less airflow/suction than bagged ones. Bagged has much more simple airpath because it goes straight through the bag to the motor.
Dirty air vacuums like Kirby or Royal have the best airflow because the fan is attached straight to the nozzle and has 2" opening. But if you connect hose to the Kirby it kills the good airflow.

This video is very informative and explains about the airflow.

 

[Reflector]

Apologizes on the hastiness and wrongful information on my part. I thought the AW formula was utilized using the maximum airflow and vacuum pressure and not when airflow or suction is held constant via diameter restriction and when the other variable is measured and used in the formula.

 

[Mike81]

Not a problem.
I used this site to calculate cfm to Philips PerformerPro which has 517 aw measured (at the hose end) by consumer reports and 51 liters per seconds airflow.
Result 51 L/S = 108.06 cfm. This should be quite realistic.
http://www.engineering.com/calculators/airflow.htm