Compatible/Replacement for Honeywell HAC504 Filter A Germ Free Cool Mist Wicking Humidifier Filter. Fits HCM 350, HCM350w, HCM350, Quietcare Tower. Fits HAC 504, 504AW - (Pack of 6)

Good filters

I've used these before so ordered again. Make sure you flip the wick over when you add water to the unit. This will keep the wick from getting too much calcium deposits on the top.

We run our HCM350 humidifier almost 24/7. So I have a lot of experience cleaning and using the machine with filters. This filters hold up just as good, if not better than the others I’ve tried.I use normal unfiltered tap water. Flip the filter every time I refill the tank and soak the filter in cold water if the out layer is feeling dry when refilling.Make sure you clean the actual humidifier with a bleach / water mixture every so often. Keep in mind this machine is in water constantly. If you have mold, you have a dirty machine and it needs some TLC.Clean the actual machine and not just the filter. Scrub down the water tank and bottom tray with the bleach mixture and make sure you rinse all of it out with COLD water.About 3 times a month, I soak the filter in vinegar for 10 mins. Overtime, there will be mineral deposits and discoloration on the filter, thats normal, thats what the filter is actually filtering out of the water!Goodluck, the HCM350 is one of the best humidifiers out there and these filters work phenomenally with the machine. Will definitely buy more.

I have purchased a couple other brands here on Amazon and these Frequent Filter wicking blue filters work the best in my Honeywell humidifier. It’s not the least expensive filter on Amazon but they last longer than those super cheap knockoffs. The blue pre-filter seems to filter out the water more than the regular ones but honestly I can’t tell the difference. The regular white Frequent Filter HAC504 filters work great too and they are slightly less expensive.

Everyone who owns this Honeywell humidifier knows these filters are the worst part of it. If you have hard water, even using filtered water they get crusty with minerals and the water tank takes much longer to empty because the filter stops absorbing water all the way up. I'm now on the third of the four pack, and these just aren't very effective. I replaced the second one early because it wasn't wicking the water up very well, but the brand new third item from the pack has the same issue. I was surprised to see the tank still half-full this morning when it should be nearly empty, and I flipped over the new filter and discovered the water had only wicked about a quarter of the way up. The cost savings aren't worth it.

Great to recieve it on time and in great condition.

They fit correctly and work well.

I was looking for a replacement filter for my Germ Free Humidifier and Thank God I found these. There is no metal in these filters. This is good because all of the other compatible replacement filters had a metal ring in them and they always start to emit a bad odor.The filters are sufficiently thick enough to have a high moisture output but aren’t so thick that they jam up the machine or fall apart. I was using another popular replacement filter brand before these, and those were a super thick filter, but it felt less dense and less rigid -  it ended up falling apart after a week of normal use. I would go with a balanced thickness, which these filters have.Awesome replacement filter - will definitely buy more in a few months.