3x4 FEET? Or 3x4 meters. Actually, it doesn't matter. My answer would be no to either. Something that small might look impressive, and they might make big claims, but the reality is that your satisfaction with it's performance is going to be smaller than it's size.

I say this as someone who's been using room air filters for decades for an asthmatic wife. I've tried a bunch of products. The only ones that have come anywhere close to BIFL are the Honeywells that use honking big air filters like those you'd find in a car. Except bigger. Much bigger. They aren't the quietest. They aren't the smallest. But they work, and when the filters get full, you can replace the filters. That can be surprisingly important - the ability to replace the filters. Surprising how many manufacturers products I haven't been able to keep going for the simple reason that I could no longer get an essential part - like a filter that fits.