Over the years I have tried multiple models of high end humidifiers (Venta, Honeywell, Vornado) and have followed the cleaning/ filter changing instructions diligently. Within a short while it seems the humidifiers emit a moldy or mildewy smell. I can’t tell exactly what we’re breathing but it’s just not fresh. Is this safe? Is it par for the course and worth the benefit of more humid air in the winter? Now we have a little one and certainly don’t want to be putting pollutants in our home.
We have been telling customers for years to get rid of their central humidifier systems. What happens is the moisture that is supposed to be getting into your rooms is getting stuck in the ductwork with all of the dust that collects. This mixture is a perfect breeding ground for mold. That is where the smell is coming from. Clean your ducts, check to make sure they are sealed at all of the seams and connections, then install a high efficiency air cleaning system, like the Electro Breeze Duct Mount UV kit at http://www.allergy-relief-air-purifier.com/air-conditioning-filters.html This is the same system used in casinos for smoke and odor control. The electronic filter is 97% efficient down to 0.3 microns (so you won’t have to clean your ducts again) and incorporates an ultra-violet light to kill mold and viruses (that keeps your A/C coils clean).
As far as humidity in your home, just get more portables and fill them with filtered water from the grocery store (about $0.28 per gallon). Distribute the portables around the house as necessary to keep your indoor humidity about 40-50%. The Electro Breeze and the portables will give you the best indoor air quality for your home. I hope this helps.
Let the humidifier dry out every so often. Water will get a stagnant smell to it eventually. As long as the water you’re using in the humidifier is clean, it’s fine. You can try using the cleaning tabs for a camelback or something. You can get them at any sports store or bike shop. They clean things you drink out of. If that doesn’t work for you, just stop using them.