wyaple
Well-known member
In this latest round of tests, I wanted to answer two questions:
1) How much performance do you lose by re-using a cloth HEPA bag and
2) How much performance do you lose by completely filling a cloth HEPA bag.
My test machines of choice (all in mint and/or fully restored condition) were a 1980 Lux 1401-B, a 1987 Kirby Heritage II Legend and a 2012 Hoover Temp Widepath. My cloth HEPA bags of choice were the Perfect for the Lux, the OEM Kirby white cloth for the Heritage and the Crucial white bags for the Hoover.
Airflow measuring devices were the ubiquitous Baird airflow meter and a GM8901 anemometer.
Results:
The Hoover Tempo Widepath experienced a 3 CFM loss when re-using a bag and a 15 CFM loss when the bag was full. These measurements were taken at the body, not the hose end.
The Kirby Heritage II Legend experienced a 10 CFM loss when re-using a bag and a 17 CFM loss when the bag was ¾ full. As it took me several months to accumulate enough dirt for this test, I was unable to completely fill the Kirby’s bag. These measurements were taken at the body, not the hose end.
The Electrolux Olympia One experienced a 7 CFM loss at the hose end when the bag was full. I did not attempt to re-use the Perfect bag this time around.
Comments:
I found out that turning a cloth HEPA bag inside out and blowing all the dust and debris out was a very messy undertaking and I wouldn’t normally recommend it. But with airflow losses in the 3-6% (3-10 CFM) range, I have enough proof that the pores in high quality cloth bags aren’t permanently clogged—at least with my house dirt, which includes some dog hair.
I definitely was surprised that ¾ to completely full bags still only lost 7-14% (8-17 CFM). The mighty Lux 1401-B still had 79 CFM at the hose end (that’s just about what new Rainbow’s start with). Even though the eject mechanism still works in the 36-year-old beast, a full HEPA cloth bag wouldn’t trigger it, but a full 4-ply paper bag will.
Enjoy!
Bill
1) How much performance do you lose by re-using a cloth HEPA bag and
2) How much performance do you lose by completely filling a cloth HEPA bag.
My test machines of choice (all in mint and/or fully restored condition) were a 1980 Lux 1401-B, a 1987 Kirby Heritage II Legend and a 2012 Hoover Temp Widepath. My cloth HEPA bags of choice were the Perfect for the Lux, the OEM Kirby white cloth for the Heritage and the Crucial white bags for the Hoover.
Airflow measuring devices were the ubiquitous Baird airflow meter and a GM8901 anemometer.
Results:
The Hoover Tempo Widepath experienced a 3 CFM loss when re-using a bag and a 15 CFM loss when the bag was full. These measurements were taken at the body, not the hose end.
The Kirby Heritage II Legend experienced a 10 CFM loss when re-using a bag and a 17 CFM loss when the bag was ¾ full. As it took me several months to accumulate enough dirt for this test, I was unable to completely fill the Kirby’s bag. These measurements were taken at the body, not the hose end.
The Electrolux Olympia One experienced a 7 CFM loss at the hose end when the bag was full. I did not attempt to re-use the Perfect bag this time around.
Comments:
I found out that turning a cloth HEPA bag inside out and blowing all the dust and debris out was a very messy undertaking and I wouldn’t normally recommend it. But with airflow losses in the 3-6% (3-10 CFM) range, I have enough proof that the pores in high quality cloth bags aren’t permanently clogged—at least with my house dirt, which includes some dog hair.
I definitely was surprised that ¾ to completely full bags still only lost 7-14% (8-17 CFM). The mighty Lux 1401-B still had 79 CFM at the hose end (that’s just about what new Rainbow’s start with). Even though the eject mechanism still works in the 36-year-old beast, a full HEPA cloth bag wouldn’t trigger it, but a full 4-ply paper bag will.
Enjoy!
Bill
