Where are you located ? In a dry or humid climate? How big is your house? How tight/leaky is your house and ductwork? In a leaky house, air infiltration could over ride a humidifier. 'We don't find any leaks' is a far cry from a real number, a blower door test is much more informative. Which Honeywell humidifier? A furnace humidifier should be wired to come on with the furnace blower, try running the blower continuously and see if the humidifier runs continuously as well. Also, the house isn't inert, the structure and furnishings take in moisture until they reach an equilibrium with the moisture in the air. There are many things to consider to track this issue down. The good thing is you're not super-dry right now, 24-26% humidity is ok, I'm at 30%.

HVAC guy mentioned coming out and hooking it up to the fan.

With your present up the only time humid air circulate through the house is when the furnace is operating. Your house is very dry so it takes several hours of air circulation to raise the humidity. You should have the humidifier set up to turn the air blower on when it is operating. If you set the humidity at 40% and all the duct work is inside conditioned space you should not have a condensation problem inside the duct work.

In Mich - so it is cold here! I believe it's a Honeywell True Ease HE200. We're in a 2400 sq ft home. So I'm confused. Right now it is wired to come on when the furnace turns on. The HVAC guy said he could rewire it to the fan(?). Is the blower and the fan the same thing? If so, then I guess that means if we have him do that what you said about running the blower/fan would increase the humidity. Quite a bit of static electricity going on so I know it's too low. Everyone I know has their humidity around 30-35%. I figured after over 3 weeks we would have reached our equilibrium!

Yes the blower and the fan are same thing.