On Thu, 17 Sep 2009 14:01:35 GMT, (GregS)
wrote:

In article , Josh wrote:
On Tue, 15 Sep 2009 19:43:46 GMT, (GregS)
wrote:

I think the mechanical actually actually saves heating costs because
it does not cycle as much buy the fine tune digital will feel a lot
more comfortable and you may not have to set the temperature
as high or low.

Many (most?) digital thermostats attempt to control cycle rates also,
either by a temperature spread setting (mimicking the hysteresis of a
mechanical thermostat), or a predictive cycle count (i.e. let the temp
spread a bit more to get N cycles per hour. That's a setting on
ours)

And some thermostats "lie" to you -- the new Honeywell thermostats
installed with our AC upgrade seem to round the "current" temperature
more generously when it's close to the setpoint (e.g. if setting=73,
anything from say 72.1 to 74.5 is shown as 73, but if I change the
setting to 71, all of a sudden it's really 74 in the room :-) I think
it cuts down on complaints, and truthfully the whole AC system works
so much better than our old one well that I don't care (and I'm
usually very sensitive to small temp diffs).

Thanks for the info.

The only thing missed was a time ON reading. I used to like
it when I had oil heat, and I could compute comsumption at
3/4 gallon per hour.

I was wondering about my air conditioner. Its a 2.5 ton unit.
Seems a bit slower than after installation 3 years ago.
I measured the current draw of only about 6 amps
at 240 vac. Not counting the furnace fan. Its got to
be low, but it works. The air conditioner man said it
should work OK but I'm only putting 1500 watts into it.
Figure at least 2 KW with the furnace fan. So if it runs longer its
not drawing much electricity.

I think something's wrong with your measurements. That would be a
SEER of at least 20 (assumes PF=1). Kinda high, I would think.

I was surprised at the tag to be used with 20 amp breaker.

Assume you're off by a factor of two (the real SEER of 10ish) and a
20A circuit is quite reasonable. That's what I would expect.

My old window unit draw was 23 amps at 240 vac,
and it was just a 2 ton.

That's a SEER of 5.4. Assume a PF of, say .9, and that works out to a
SEER of 6, which isn't unbelievably bad for an old AC unit.