Product review (5 stars): I was really disappointed. However I was able to find the HDC-12 ...
I live in the Midwest, and during the winter the air here gets really dry.  I picked up a consol humidifier a few years back from a big chain home improvement store.  I was figuring I could also get the filters from the store in the years to come.  The following year when I went in to get filters for it, they were no where to be found.  I was really disappointed.  However I was able to find the HDC-12 type filters on Amazon and purchase them that way.  They were even cheaper than anything in the store.  I use water treatment in my humidifier too, and with that I can make one set of filters last the whole winter season (usually anyway, I do check to make sure they have not turned completely crusty).  I found these filters purchased on Amazon to be the same quality as what I originally purchased in store.  To me they make a world of difference.  Without a humidifier I wake up with sore throats and sinus problems all winter.  Running the humidifier solves all these problems.  I highly recommend if you live in an areas were you have to run the furnace extensively in the winter.