A Whole house humidifier would typically be installed in the return air plenum. The bypass type has a duct running from the supply plenum to the humidifier. In your situation if you can mount a humidifer on the return at the furnace, the Aprilaire 400 model would be a better choice at 0.7 GPH. Dan Martyn Here is a link that might be useful: AprilAire Model 400

Typical console humidifiers (drum style) can require a lot of care to keep them free of microbe growth. If you are willing to add bacteriostatic chemical to the reservoir, not as much is required. Otherwise, i'd say that the reservoir and pads need to be cleaned and disinfected daily. Hardly anyone has the patience to do that. Think about it, you have a porous surface at room temperature 24/7. It is not unlike a wet towel with one end in a bucket and the other suspended above 24/7. What is going to happen? With a duct mounted model in a force hot air heating system, the most common type, bypass humidifiers (AKA drip, AKA flow through) require only monthly to annual service and it is not difficult for a somewhat skilled homeowner. There is little to no chance of excessive microbe growth if maintained properly. I'd avoid the drum style there too due to high maintenance demands. The best systems, if money is not a problem, are steam injectors, but they are relatively costly to install and run. You really want to make sure that your home is well sealed as a first step. Look up what humidity levels can be maintained in colder weather. If you are hovering at 0 F, you may not be able to go above 25% without condensation on your windows. With even lower temperatures, you are limited to even lower humidity. You have to adjust your settings according to outdoor temps. Don't buy one with unrealistic expectations because of that limitation.

My climate is similar to yours, and I could not LIVE without my whole-home humidifier. It is by Aprilaire. If you don't have one, then, as you mentioned, your wood floors and cabinetry will suffer. More importantly, you will also personally have dry skin and nasal passages. You will get a spark every time you touch something, including your pets. Regarding Mishmosh's comment of only increasing the humidity a little, you do not want too much humidity in your house in winter. That would cause severe condensation issues with your windows. On the Houzz Windows forum, this winter condensation issue comes up all the time. Here is a link to one thread, but there are many. You want a humidifier that will make your home's indoor winter humidity about 30%. Your concerns about mold are unfounded; you will not get mold at 30%. In my home, in winter, if I didn't have a humidifier, my indoor humidity would be 10-15% which is very uncomfortable to live with. You will definitely benefit by spending the money to add a whole house humidifier. https://www.gardenweb.com/discussions/5556880/massive-condensation-on-windows

I had the Honeywell equivalent to that. Very finicky units. Need to dial in the water supply to the evap pad VERY carefully, and check for the drain line being clear at all times. If your water has iron or is hard then the pad's lifetime will be severely shortened. You might be better off with a steam humidifier which goes into the supply duct. Expensive + maintenance. Watch your humidity level in winter if cold so that your window sills do not dissolve.