"Stretch" wrote

Many heat pump setback thermostats lock out strips during the beginning
of setback recovery. On those, recovery takes a LONG time. After a
number of hours, the strips are allowed back on, recovery occurs and
electric bill goes up.

Note that recovery without strips only works in mild weather, so
setback efficiency depends on your climate. It does not work well in
my climate.

I have a 12 year old thermostat (Chronotherm III) that has the adaptive
recovery feature as you suggested. When the system comes on (when coming out
of a setback), it will try to reach the set point without bringing on the
auxilary heat strips. It will only bring them on if it "looks" like it's not
going to meet the set temp at the time set. Seems to work pretty well, but
if it's down in the 'teens, forget it. That's when the gas logs kick in
anyway.....;-]