Lucille: my brother had those hepa filters for every room also. He insisted I get them for Mom when she came to live with us in 2002. I did. She cleaned the one in her room all the time and it was always black. I don't know what that says about my house. it is an 1890 home but it has storm windows on all windows and good new a/c-heater system. We change filters and they are always awful. Momma is gone and so are the hepa filters. I couldn't keep up with that and the sound of them humming made me a little "nuts" :) I have dust on all surfaces so not much help to you I guess. I have a vacuum that has a canister and a removable filter to wash. I empty it and wash and dry and go over everything again. Change a/c-heat filters ...still there is dust. If you have allergies I don't know how you stand it. Guess it depends on what part of the country you are in. I sympathize for sure. Have you looked into a better a/c-heater system with built-in cleaners ? c

I have a high-end HEPA air filter for when a smoking relative visits, and it is not hard to use up the filter just with regular invisible housedust and cigarette smoke. They work, and work well, for my purposes -- but I can't imagine the expense of trying to filter construction dust around the clock - the replacement filters are quite pricy (like $179), and you'd be replacing it every other day or so. I think the best use of HEPA technology is for more silent pollutants like pet dander, cigarette smoke, etc. Drywall dust will clog any filter within an hour, especially a fine one like HEPA. You might do better to specifically let your GC know about your dust concerns, and have them set up plastic barriers to the rest of the house, etc -- they can get fairly high-tech these days, with zippers and fans and whatnot. Good luck!

I have to have air filters in my home for health reasons. I have 3 Austin Air filters, and 2 Rabbit Air filters. Their are things you should look for. Look for CADR-( clean air delivery rate) that is how much filtered air the machine produces. Their is also an ACPH( air changes per hour) people with asthma and allergies need at least 4 acph. Also look for a TRUE HEPA not a Hepa type. 2 very different filter types, a Hepa type doesn't filter out the small particles that a true Hepa does. You want to look at filter replacement cost because ALL true Hepas require filter replacement. Their are no permanent true Hepa filters. Also look for ozone information. filters that produce ozone are harmful, and must be avoided. Some people care about how much electricity their machines run, since for the most part filters are run 24/7. And noise. Some people want ultra quite filters, that produce zero noise. Which isn't super realistic it is blowing air after all. You must think about where you will put it. My filters require X amount of space on each side to function properly. My Austin airs have 15 pounds of activated carbon in the filter to also absorb odors and some chemicals.The filters are a bit more expense then my other filters at $214, but last for 5 years. They are more basic-turn the knob to one of the three settings, and thats all. Basic, but very effective. To change the filter you turn the machine upside own, unscrew the bottom, and pull out the old filter and add a new one. The maintenance is vacuuming the sides of machine, and wiping it down it it's dirty. I also have Rabbit Air filters. These have much more settings. I bought the style that mounts on the wall, which would be excellent for children's rooms, so they are up and out of the way. It come with a remote too. The filters are replaced once a year for about $85. This doesn't have the 15 pounds of activated carbon, but does have a small amount of charcoal to help with odors. They have a decal on the front so they actually appear to be art work hanging on the wall, which is very nice. My rabbits in auto mode will automatically go into sleep mode when the lights in the room are dimmed or turned off. The filter is still running on the lowest setting and I almost can't hear it, and the lights turn off as well. The filter change is easy. Remove cover, and change filters. The maintenance is cleaning filter quality sensors, cleaning top vent, cleaning light on front panel, and wiping down if dirty or dusty, and vacuuming the prefilter once a month. It isn't too bad or too much of a time suck. Before buying I recommend reading an owner's manual online. It might open your eyes to thing you hadn't thought about. I also recommend getting a machine that filters a much larger room than your daughter's room, this ensures she is getting good clean air and a higher acph rating, which is very important for asthma and allergy sufferers. I did a lot of reading before I bought my machines, and I would say both are great, and I would buy them again without a second thought. That's all that I got at the top of my head, so I hope that helps. Good luck to you and your daughter, Harlow

Choose the add ons that are important to you and then pick the cheapest way to get those options. HEPA is great for filtering the air, but the charcoal filter is better at reducing pet odors which is why most pet models dont come with hepa filters.