Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Cutting the pre-filter is a real pain. I am running each I bought w/o the pre-filter. I cannot see that the permanent filter is collecting any dust?
Document: The permanent HEPA filter apparently does nothing. I have run the units without the pre-filter for weeks, and using a powerful flashlight I can see virtually no dust on the permalife filter. I had ionic silent air cleaners, and I am going back to them. Running the fans on 4 of the Hunters raises our electric bill quite a bit, and they are not cleaning anything out of the air.
I bought this air purifier for my living room which is approximately 400 square feet. This air purifier does a pretty good job at knocking down the dust in the air. When I leave it running a few hours, I notice the rooms feels a lot fresher. The permanent filter is nice and isn't a pain to clean. I'd recommend it, since it works without a lot of fuss.
Bought it for use in our den where our dogs create a huge problem with hair and dust. So far so good. The air quality has definitely improved and dust and hair disappearing. Be aware that it has a pre filter and as I haven't had to replace that yet, I am not sure how much of a headache that is going to be. Hopefully none....
I noticed the difference within an hour of plugging this in. I have 4 dogs that all want to be in the house with me. Living in the country I have lots of dust, and with dust allergies, my doctor thought an air purifier might help me. I bought this one because of the permanent filter, small foot print, and replacable prefilter. I have only been using it a couple of weeks, that is why only the 4 star rating.
I've had this for about a year now. It worked great for the first few weeks and I really noticed a difference. Now? Even though I have cleaned the filter, I'm not sure it is even doing anything anymore.Can't seem to find replacement pre-filters for it anymore either.On the plus side, it is quiet, so I don't really care that it is running.
This appears to be a fine, no-frills air purifier that does the job without costing an arm and a leg.I had a Bionaire ULPA filter for many years, but there has been so much construction in my NYC neighborhood of late that I was replacing the main filter (still available online) twice a year. That's about $160 just in main filters a year -- and more in carbon pre-filters.So I was attracted to the claim of a permanent filter on this Hunter.
feet, so we had to use a bigger purifier than many of the residential quality ones on here are rated for. We didn't want to break the bank, and would prefer not to pay $50 for a replacement filter in a few months. With it's permanent filter (and affordable replaceable pre-filters) this one has fit the bill!
Hunter 30793 PermaLife large room Air Purifier with Permanent Filter fell very short of what it was expected to do.It cost me a lot of money & I wish I could return it.A real waste of money.Hunter 30793 PermaLife Large Room Air Purifier with Permanent Filter
Air Purifier works pretty good. I can definitely tell a difference in the air quality since purchasing it. I don't see those little dust particles floating around when the light shines through the house any more. There's dirt all over the filter, so that's less dirt being breathed in. I don't have any allergies, but I was just tired of having to dust constantly and the filter has done its job at changing that.A negative... but not justifiable for a star down.
I use this to lower the amount of dust in my office.Pros: washable filter will save you some serious cash over time, it works pretty well, the v shape fits well in corners.Cons: it is pretty loud when running on high.I have only tried one other air filter, the honeywell desktop model. That one broke down after a year or so. The bearings wore out and it started making strange noises.
Answer: I vacum my original prefilter and I can also use it to size the new roll of pre-filter sheet when I çut it.