Not sure where the Festool 1 micron filtration number
came from? Everything I have read say .3 micron with the Festool Hepa filters…
I have the CT-36 and have been very happy with it. Pricey… Yes. But it’s been worth it…
Only caution……
The “Green Festool” slope is a slippery one…. 
.
Proceed with caution…… after the first purchase… each additional purchase gets just a little bit easier….