Choosing a humidifier can actually be a bit complicated because every home is different.  Typically an old home that has leakage due to old windows and doors, lack of wall and attic insulation or maybe in an area with heavy winds and where humidity levels are ranging from 25-35% is where humidifiers are needed.  Some homes are harder than others to raise humidity levels.

Some models we offer are:

Drum Style:

Not as popular and require more up keep.  You may also get water leakage due to floats.

Fan assisted flow through:

Works the same way as a flow-through model but has a fan built in the humidifier to push a larger volume of air across the pad to help raise humidity

Flow Through:

When humidistat calls, furnace is in heat mode and water trickles down a pad and the bypass damper captures the moisture and pushed it into the home.

Canister style:

Much more costly but when needed it will do what it needs to