[Vicegrip]

in line uses its own fan to move the air. bypass needs two holes and uses the furnace air blower for movement.

in line the easy one to install only one somewhat good sized rectangular hole, one water in one drain out and 24 volt power from plug in trans. the fan motor will (not might, will) fail after some time but that might be years "April aire" is not a bad unit at all uses an easy to get evap pad and is easy to install. Just cut a hole using the template and some tin snips, mount the unit, (to the furnace, you pervert) hook up the sensor, water, drain and power then read the instructions to tune the water flow.

The more humidity the air has the warmer it will feel at a given dry bulb temp. Dry air feels colder than properly humidified air. Too much moisture and the air will feel clammy and the windows and walls will sweat.

[Eli]

THanks for the advice. From what I gathered so far, on and off the board, a professionally installed central unit will run me anywhere from $400 to sky is the limit. I will look into hooking one up myself in the near future.
For now, I picked up two honeywell units (one for each floor), which will keep the kids (and myself) from waking up at night complaining about dry sinuses...

[William Miller]

I have an in-line unit made by carrier. It has an aluminum pad that goes bad after time. If not checked it will clog up and leak on the basement floor. (Simple to change the pad and has a clear drip tube so you can see immediatly if it's working)
I imagine some of the longevity depends on your water and how it reacts to the pad material.
I have mine tapped into the hot water. (IMHO it helps some)
I think there are also different ways to hook up the control wire. (I think mine was initall set up to run with the fan but I think I moved it over to only come on with heat.)

With a heat pump humidity becomes very important since the outlet temp is so low. With the humidifier working you won't feel as much need to raise the thermostat. As everyone also said good for the woodwork and the sinuses. It will also help you figure out how good your multipane windows are. Single pane will sweat. Will also cut down on static electricity

If you have the space next to the duct they really arn't that hard to install after the fact.

If the furnace is an unconditioned area like the attic there are other considerations.

[Eli]

Bill...I goofed on your address. Just got the CD back with a big stamp "RETURN TO SENDER" could you PM me your address again? I'll overnight it this time around so you'll at least have it this year

Thanks!

[William Miller]

Eli, you have mail!
Thanks!

[Don Wohlfarth]

I've been in the HVAC service and repair business for ~40 yrs.
Aprilaire is pretty much the standard for whole house humidifiers. A/A had the patent on the design and that has expired. There are several humidifiers that have copied the design including Carrier and Honeywell and those are good units as well.
These 3 units are fresh water humidifiers, whatever water is not evaporated goes down the drain. This carries away the salt deposits, calcium, minerals, etc. When the unit cycles off they are dry. For mold to grow you need a water source.
Whole house humidifiers operate in a hostile environment, it's warm, humid, and no sunlight to purify anything. Humidifiers with anytype of reservoir should be avoided or cleaned regularly(once or twice a month).
All humidifiers require some maintenance. Fresh water ones require the least.