Thanks for the answer!

I have only had my Resmed S9 since early June. Even though both the manual and my RT say to change every 6 months, I changed the filter after 90 days. I have 2 dogs and there is a lot of hair and dust floating around this house!

Yes, I know that the original Resmed filters feel the same on both sides. I was asking about the filters not made by Resmed---the ones sold by cpap.com ---- which I am using now.

I recently bought a package of the cpap.com generic filters for the Resmed S9. I have noticed that one side is smooth and the other side is a bit more textured. What side should be facing in towards the machine?

Thanks!

I have been on cpap now since May, 2009. Up until now, I have been reading this site everyday and using the wonderful advice to help me get through this very difficult first year. Without the support of all of you more experienced cpap folks, I don't think I would have made it. It was so good to dis...