On 1/24/2013 3:32 PM, ps56k wrote:
What with all the various eco topics concerning when and how to run your
heating/cooling,
I have yet to see a home electronic thermostat with the added feature of -
- an elapsed run timer -

ie - how long has the system run since timer reset ?

This would be great to see if setting the temp higher in summer,
or a little lower in winter actually changes anything
while being able to record the amount of time the furnace or A/C runs...



I did the experiment. Put a flapper on a microswitch and stuck it on a
register.
PDA graphs the percentage on-time for each cycle. And keeps a running
average.

http://imageshack.us/photo/my-images...mondisplay.jpg

Most interesting thing I learned is that the house has a very long time
constant.
I turned the thermostat from 65F back to 60F and went to bed. Was in
the low 30's outside. 7 hours later,
the furnace still hadn't come back on. When I added up the run-minutes
to get the house back up to 65F and compared to what it would have used
keeping the place at 65F, the difference was in the noise level.

Another interesting observation is that when I wake up and turn on the
computer, there's an observable drop in furnace output. Kinda interesting
to watch for the first week. After that, not so much.