I've had the same batteries in my 3 thermostats for 6 years with no
problem. Pretty amazing when I think about it. I know they still
work because usually once every year, the float gets stuck in the
condensation pump on one of them and that causes the safety to cut
power to the furnace and the thermostat goes on battery till I fix it
(clean out the algae). I have 3 separate HVAC systems. Wouldn't
screw around if I only had 1.



"George E. Cawthon" wrote in message
...
Work for a battery manufacturer do you. I just replaced my
thermostat battery when a problem with my furnace appeared.
The battery had no affect on the problem and was still
functioning. But it was 28 months old. Replaced the
battery in my battery operated smoke dector last week
thinking the tweet came from it. Nope it was a CO monitor I
forgot about, but left the new battery in the smoke detctor
anyway. The old battery was dated 01/24/01. The previous
battery last well over 2 years also. Several years ago I
started putting a piece of masking tape on all batteries
with the replacement date, so I would have some idea how
long they lasted. Well, know I know. Changing ever year is
a waste of time, and changing every 6 months is a waste of
resources.

If the guy is worried, he should change the batteries in
critical equipment before he leaves. I don't, but then I
check the date on the battery and the operation of the item.

Joe Bobst wrote:

I want my house to be more proofed for things like temporary
power outages,
etc, in case we are not around.

Do what everyone else does with these thermostats - put in new
batteries when
Daylight Saving time rolls around. Why get all worked up about
something that
is your own responsibility? You can get control systems that are
fail-safe and
fool proof, but unless you have a seven figure income they may be
priced beyond
your budget. Odds are your batteries had gone way beyond their
stated effective
life, so if you tend to be forgetful, get the highest quality
replacements on
the market.
Maybe a warning tag on your furnace filter compartment would be
helpful for
next year. HTH

Joe