"Ken" wrote in message
My question is this: I can understand the impact of the stairway on
cooling the upstairs, but why did the heating of the upstairs respond
poorly as well? I feel I am overlooking something simple, since I know it
DOES impact it by the results I achieved.

A lot depends on the air currents too. If you have heat pouring into the
rooms and nothing hitting the thermostat, it will be very slow to respond.
You can also get cold air currents going by the thermostat and down the
stairs too.

Light a candle and stand in the stair well. Move the candle from floor to
ceiling and watch the flame. You'll suddenly understand a lot.

Ed