Humidifiers are used when necessary. They can cause mold. If the duct is flex, cleaning is difficult at best. Cleaning can ruin the inside plastic. All duct should be wrapped. I use a blanket that is 5ft wide and about 60 ft long. I seal all joints.

Is your furnace easily acessible? Most humidifiers I have installed mount on the cold air return plenum and use a bypass duct from the warm side. I like motorized drum humidifiers, plate types waste water. I clean my humidifier twice a month during cold weather, any less than that and you're asking for trouble.

-We feel the home is very dry hence the unfortunate necessity. I can honestly say I've never felt like this before. We wake up with dry throat, dry eyes and lips, etc. It wasn't like that at my folk's home ;)

Plus with all our wood flooring, I think some humidity is needed.

To comment on what's been said so far, thankfully, NONE of the ductwork is flex. It's all that tin/metal tubing. So first, as you described, I would seal all the joints, then wrap them with some sort of radiant heat insulating sheet. (That was what I saw at Lowes.) Any other recommendations on what to wrap them with?

The furnace is pretty accessible. I was actually looking at a Honeywell model and considering mounting it just as you described, with the bypass on the cold air return and warm air unit on the hot air. In fact, I'm gonna take a photo now....

"A" is where I was going to install the drum, "B" is the return where I figured the bypass duct would go and "C" is the furnace. Did I tag that correctly?

Oh, and B is where there was an old humidity humidistat that was removed and simply replaced with duct tape.

I only saw the plate type humidifers at Home Depot. Tell me more about the drum type. And please let me know any recommendations on what models to get. THe home is small, about 1300 squ feet.

Any recommendations on brands, etc?

Here is a link that might be useful: {{gwi:1546402}}

I have a Honeywell model HE 120 drum humidifier installed this past November. It was about $140 at Home Depot.

I would mount the humidifier unit somewhere near point B, probably along the back of the duct. Install your bypass duct and damper somewhere near A. The instructions will tell you the best place to install the new humidistat. Most are designed to just plug in but I wired mine to only get power when the furnace fan operates.

Good luck.

Thanks. I'll be looking for that model. THanks!

I have a 6mo old EWC Auto Flo S2000 residential steam humidifier (110 volt) that I took out of my old house that I was going to try and sell...if you are interested. It mounts in the duct and has a pretty small footprint. It would need a dedicated 120 volt outlet because it works by boiling the water with an electric heating element and it draws 15 amps. But the benefit is that you dont get the white dust from the calcium residue all over your house like you get with a regular humidifer. It is pretty expensive, but I think it was worth it. I got a larger 220 volt steam humifier for the bigger house.

Info:
http://autoflohumidifiers.com/humidifiers/steam-humidifier-S2000-S2020.html

See link below

Here is a link that might be useful: EWC steam humidifier

heres what we use to insulate ducts

Here is a link that might be useful: duct insulation