Ok. I've been looking into this a lil and there are better options than a cr box.
Housefresh has been looking into this and they recommend the nukit tempest or luggable XL or another one - think it was a Canadian brand - as the cheapest total costs over time and lowest sound and most efficient purification. All of those use regular HVAC filters which cuts down on operating cost and are quite big which cuts down electricity and sound.
So recommend getting one of those for long term use, if you have the space for it.