On Thu, 12 May 2005 01:08:45 GMT, jay wrote:
I recently installed a Honewell programmable thermostat. The manual says
"model number CT3500/CT3595". While this device seems to keep the house at
the target temperature, I find it odd that it can turns on when the
temperatue is already stated as being the target temperature. Note: I have
"Smart Response" DISABLED.

It is because the indicated temperature leans somewhat towards the set
temperature if it is within a couple of degrees. Notice that when you
change the setting by one degree, it indicates that set point, even though
the actual temperature does not change that fast.

However, it has adaptive anticipation that usually controls termperature
within less than 1 actual degree. So it does maintain better comfort than
cruder thermostats that go one degree from set point before they turn on
and a degree the other side of set point before they shut off (2 degree
spread plus overshoot).

I was very satisfied with the CT3500 for my steam heat. The only reason I
changed that out to CT3600 (7 day vs. 5-1-1) was to monitor boiler run
time (current day, previous day, and total), so I can tell how effective
setback is. Either was better than a RobertShaw, which was +-1 degree
with no anticipator (2 degree spread plus 1-2 degree overshoot).