Steve B wrote:
"LouB" wrote in message
...
Tony wrote:
Bill wrote:
"Tony" wrote in message
I'm trying to figure the cost of running the central AC in my house.
If your heating is other than electric, then the cost is the difference
in your electric bill from the winter to the summer.

Or if there is a month in the spring when you don't use heating or A/C,
then the difference in the electric bill from that month and a summer
month.

Hint: If you get a couple of window air conditioners and just cool the
room(s) you are using, the cost will be lower. So just cool the living
room during the day and just cool the bedroom at night. If you have 6
kids and 7 bedrooms, then not much savings of course!
That's exactly what I getting at. I'm almost positive it costs less to
run 1 or 2 8,000 BTu window units than the central ac, even if I close
off the rooms not being used.

I suppose if I compared oranges to oranges and converted both central and
window rattler to a basic BTU's/watt that would be very helpful, but I
still need the specs on my compressor.
Have you sought help from your electric company?

Have you looked on your bill and read the $/kwh? Compared the chart for
month to month, and this year vs. last year comparisons?

Yes. But comparing last years to this years has too many variables.

AC, in my estimation, has to do with keeping things cool. Once a room is
cool, it takes less power to keep it cool than to cool it down from warm.

I'm with you there.


With central units, they will do this better than room units that have to
cool a warm room. Up. Down. Up. Down.

No up down up down here. In this 93F weather the little 8000 BTU unit
runs on high 24/7 unless it gets too cool, then I turn it down. Cycling
it makes it less efficient.

But, then, the only way you find out is to install central, and do a post
mortem analysis.

I have central. I believe it costs much more to operate than a window
unit or two, but it's hard to say without the right numbers.

Right now I have one 8000 BTU unit and one fan to circulate the air.
Running it 24/7 30 days would cost me less than $60. It never runs all
night so it's maybe $45-$50 a month to cool 960 sq ft. Forgot the fan
to circulate the air, add about $4. per month.



Sometimes a large central AC won't have to work as hard as several smaller
ones. But then, there's the thing of cooling unused space ......... It's
hard to say.

I always considered "work as hard" an odd expression in this context. I
had a Fedders, maybe 7000 btu run pracically 24/7 each summer for 15
years and it never stopped working. I left it at my old house because
it wasn't nearly as efficient as the newer ones.