Where are you located? How are you measuring the humidity level? What model humidifiers do you have? What is the temperature outdoors and indoors?

A reading of 16% is very low. My first thought is the reading is not accurate.

I have one of those acu-rite digital thermometer/humidity. It does feel very dry. Thats why I am so frustrated. I live in Chicago. The temperature outdoors this week has been in the -5 - 10 degree range. The indoor temperature is between 68-70

I have the Acu-rite device also. It is not a precision instrument, but it should should be close.

Have you tried setting the thermostat to the fan on mode during the day to see if you can more moisture in the air? It is hard to believe you have two humidifiers and you can't get the humidity above 20%.

Hi Melissa, Those inexpensive instruments often work pretty well, but the problem is that you never know if they are off so you have to buy two for a check method. A sling psychrometer as a check is probably better. You can get a good used on on ebay for not much money. They are either working or broken and you know right away.

16% is, indeed, unusually low. At -5 F, however, it is quite possible. To illustrate, if the outdoor temp is -5 and the relative humidity is 50% the dew point is -19. If the moisture in the air (absolute humidity) is equilibrated indoors and out and the temp indoors is 70 F, the RH is 2.4% using the -19 dew point. Just living in the house increases humidity, breathing; washing yourself, dishes, other stuff, house plants,.... That added moisture has to be retained by the structure. If you have a leaky home, indoor humidity will be lower than if it is well sealed.

Your humidity may be 16%, or it may not, but if you feel it is dry, it probably is. First, make sure that you have good measurements. Second, turn off the humidifiers and see what happens to the humidity. Compare what the humidifiers in your HVAC system are doing compared to running a self-standing drug store model, a pot or two of water simmering on the stove, running the shower HOT and maybe some other things you might think of like drying a load of towels with the dryer vent unhooked if you have an electric dryer. Do all of these things at the same time if you desire. If nothing makes a dent, you may have a very leaky structure and the leaks could be in your heating ducts. That turns your HVAC blower into a power vent if the ducts are outside of the envelope. In fact, any one or two of the above should raise the humidity to a comfortable level in a reasonably-sized and reasonably-sealed home.

If air leaks are letting the humidity out, spending the kilobuck on sealing the leaks might be a better investment than another humidifier.

sling psychrometer

There are simple methods to calibrate a hygrometer. Do a search and you will find videos on YouTube.

Yes, the ones I am familiar with use water-saturated mixtures of common, or less-common salts. They are simple, but I am not certain that method is more simple or less expensive than a sling psychrometer. The latter is a very easy instrument to use.

Ok calibrating the instrument. However I don’t think the humidifier I just fixed is working. Spent 300 dollars and now need the guy to come back out. Someone had mentioned that running the fan would bring more humidity. How does that work? My house is drafty. Bad windows and doors but I don’t have the money to fix that pronlem

Also if anybody had a good Hvac guy in Chicago I am always looking for a good one. Have sunk a lot of money into bad ones unfortunately

Running the blower constantly increases the humidity? That is not likely to help much and may make things worse. it will also cost money to run the motor. Where are your ducts located, inside the building envelope, or outside (like the attic or in a crawl space)? If outside and leaky, you can get a lot of outside air that way.

Cover leaky windows with temporary, plastic film window kits or bubble wrap. Get some caulk and a good caulk gun and some weatherstripping material. You can do some serious improvement with this stuff.

I suggested running the fan as a way for the humidifier to run and circulate the humid air. This assumes the humidifier is operating correctly. No need to do this if you a set up where the humidifier turns on the blower whenever the humidity is low.

Mike, my understanding of drum and bypass humidifiers indicates that they do little unless the heat is running. In addition to that, if the OP has outdoor ducts and they leak, constant blower will draw in a lot of outside air further bringing down humidity. A steam injection humidifier will operate when heat is not called. My limited experience indicates that bypass types predominate.

If what you say is true then the furnace would have to run many hours in a day to increase the humidity level. Not a good set up in my opinion.

Mike, from an operational standpoint, the need to add humidity is proportional to the need for heat and the cycle on time for the furnace. That might not work 100% of the time, but plenty well enough to satisfy nearly everyone.

In my view, the plastid/metal pad or -bypass humidifiers that I am most familiar with, are most often installed, I think they need hot air to be effective. Of course, any humidifier can put more humidity into an air stream if the air stream is heated. Steam will be the least affected. I would not even consider a drum type — too much trouble and too much opportunity for microbe growth and high maintaince. If some special climatic conditions make it so the most common set up does not hit the mark, Maybe a steam injection system would be warranted. I think that I remember ultrasonic units were considered at some time so it might be worth looking deeply. They spray out a lot of mineral powder, but a filter would take care of that.