Dear Will:

"Will" wrote in message
...
My vacuum cleaner does not have a HEPA filter and I
would like to get a cleaner that does.

You like the benefit of efficient particle removal of a certain
size (or larger), and you are willing to pay more for the bags,
buy more of them, and change them more frequently.

Can someone who understands the physics of HEPA
filtration help me understand HEPA a bit better please.
Google is not much of a friend for this info!

-----

Is HEPA a registered trademark?

No, but it is a recognized standard acronym.

What technology does a HEPA filter make use of?
Is it nothing much more impressive than a very
fine aperture standard filter?

Correct. Yet there are small modifications that can be made to
the element to extend service life... by a few minutes.

is the HEPA filter on a vacuum cleaner likely to
need replacing more often than non-HEPA on
account of the greater dust it traps?

Not "greater dust". It has a small pore size, and using it means
blocking the small pores will block all flow.

Can a HEPA filter be washed or otherwise
cleaned so that it can be reused?

Possible, but not likely. Water carries contaminants, and these
contaminants scale out and block small pores.

Or is the life of a HEPA filter so long that this
is not a consideration.

Anything one could do to extend bag life, or reduce the number of
bags used per annum would be a sales feature. But then, once you
buy the vacuum cleaner, they have hooked you for replacement
bags. Just like ink jet printers...

Thank you for any info.

You have good links by the others.

David A. Smith