Installing natural gas furnace (Carrier Infinity...

Carrier Infinity 96... Carrier's MVP furnace.
variable speed blower - quiet and reliable.
circuit board controls humidifier power (24VAC),
whether it be a "Carrier" or "AprilAire" brand

Carrier furnaces have a humidifier "tab" on their boards,
eliminating the need for a secondary power source.
The humidifier low voltage power is controlled
by the circuit board on the furnace. It will not
"run all the time."

This depends on what humidifier you are getting.
The "basic" comes with a cheap humidistat which can
can be used to control the humidity.
OR
You can have a Carrier Thermidistat installed,
which comes with an outdoor sensor to control the humidifier
without the need for a seperate humidistat. The same holds
true if a Carrier Infinity Control is installed.
OR
You can have either a Carrier or an AprilAire humidifier that
has an outdoor sensor included with a special humidistat that
controls the humidity more "smartly" in your home.

Hot water works best for evaporative-type humidifiers,
no matter what "brand name" they are.
Since this allows for better and quicker humidification,
it reduces the amount of water required to add humidity
in your home (less drains out since more is added to the air).
This reduces your water bill.

you're welcome.

peace,
-Gate