Im pretty confident that the AC is not the issue. It was replaced with
a new unit inside and out (new digital thermostat as well). The house
stays cold, unusually cold. I dont understand why my electric bill is
more now with a new AC unit set on 80 and feeling like 50, than it was
with the old one set on 60 and the house staying at a temp of 80-85.

dpb wrote:
Kravynn wrote:
I am renting a house. It is a block house built in the mid-late 50s.
...
landlord to get a new AC unit. I was anxious to see my "new" electric
bill, only to be devastated when it came in at $465! I started turning
off my water heater during the day, desperate to save money. I keep
the AC set at about 80-82, and it stays pretty cold in the house. This
leads me to believe that the thermostat may not be working properly. At
any rate, another month has passed and this bill came in at right
around $400. My brother is an electrician, he said I probably need to
have the breaker box updated, to much power running off a 150 amp main.
I know that there have been 2 rooms and an AC unit added to the house
since it was built. I would appreciate any suggestions, ideas,
input....My electric bill is more than my rent at this point. I'm a
single mom and I'm in a state of panic.

All other posts (so far) reasonable suggestions altho ditching the new
central A/C for a window unit seems extreme before finding out more...

I'll second the thought that the service panel isn't the cause of the
high usage (and a high bill implies high consumption).

There is one possibility not mentioned so far although I suspect it
won't turn out to be the primary culprit but that is it is possible for
a meter to go out of calibration. The utility company will check them
on request.

I suspect Bob nailed the primary culprit--given it's a 50's block house
in FL, one would suspect it has very little if any insulation and quite
possibly a lot of leaky (as in air flow) windows and doors, air
infiltration around electrical outlets, etc. -- iow, the house is
probably just not at all energy efficient. Your local utility company
may also still have consumer energy-efficiency teams that will do
inspections for no or little charge to point out specific areas that
can be easily fixed. The "feels warm" test on the ceiling someone else
mentioned is a real good clue that you have a problem.

Another mentioned that the landlord almost certainly replaced the old
unit w/ another as cheaply as possible means the efficiency may not be
much, if any, higher than the unit it replaced, only that it has a full
charge so will actually cool. Some old wall thermostats are
notoriously inaccurate to begin with and only get worse w/ age--if a
new thermostat wasn't installed w/ the new AC it's quite possible it is
off by several degrees. The old one here has a seemingly variable
amount of hysteresis, particularly on the "off" side--it can sometimes
seem to be 3 to 4 degrees below the setpoint before it actually shuts
off. Checking actual temperatures w/ a good thermometer to see where
it really is is a good idea. You also might experiment to see if you
leave the fan running that you could set the thermostat several degrees
warmer and still be reasonably comfortable, as well.

In the end, if you discover (as I suspect) that the above factors are
all true in greater or lesser degree and the landlord isn't willing to
improve the house (and it's highly unlikely he'll want to put in yet
another, more expensive, A/C anytime _real_ soon ), your best
alternative at that point may be to try to find a more energy-efficient
place to live.