Coway AP-2015F(G) Airmega 400 Smart Air Purifier

The dimension of the unit are 14.8 x 14.8 x 22.8 inches. It weigh 31.5 pounds.

Yes, there are several third-party manufacturers. Unfortunately, quality is a gamble. At least with Coway filters you know you're getting a perfect seal and true HEPA instead of HEPA-like.

The Air Mega sucks in some air and blows out some air. If you don't mind your curtains blowing a bit or being sucked towards the unit, then by all means, place it near curtains. If you are worried about heat, it is not hot.

No, there is no ionizer. That is why I purchased it. I own 4 units and happy that it is easy to clean.

Any air purifier works best in a more central location. The key to good filtering is airflow. This particular model (I have 2) draws air in from either side and expels clean air out of the top of the unit. There is no issue placing it up against a far wall, but again placement helps. I'm not sure it would be very good to place it in the corner of a room especially if you put it directly up against a wall because you'd block or diminish 1/2 of the incoming air from being filtered. You'd definitely not want it right up against the wall especially if it was really close because it might lead to premature engine wear if it was working harder to draw in air. Say you have two rooms that you want to filter. It's best to put a smaller filter in each room rather than one large filter centrally located, regardless of what the CFM / SQ FT specs indicate. I've talked to a couple of tech support people at one of the companies and read a bunch of FAQ and that was the big take-away