I plugged my window AC into a "killawatt". It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

On Jul 12, 1:09*pm, kansascats wrote:
I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

Somewhat, but don't forget even if shaded, the air temperature around
the unit is rising even if the unit is not in direct sunlight.

On Jul 12, 2:50*pm, jamesgangnc wrote:
On Jul 12, 2:09*pm, kansascats wrote:

I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

It's been suggested and disproved that shading the outside half of ac
has any notoicable effect. *What you are seeing is the reduced
transfer rate of heat to the atmosphere because of the increased
outside air temp. *This raises the high side pressure and makes the
compressor work harder.

Bottom line it's not the sun beating down on it. *It's the higher air
temp.

You might think shading the unit has no effect, but it does. The
biggest thing is the whole wall in the sun. The brick or siding really
heats up the whole intake area.

You need to shade the whole wall.

Greg

On 7/12/2011 1:09 PM, kansascats wrote:
I plugged my window AC into a "killawatt". It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?


There are a lot of factors that can contribute to increased power
consumption with a dirty coil being one of them but what first came
to me as I read your post was the fact that the voltage in the grid
may be dropping as more and more people run their AC units. When the
voltage drops, the current goes up and the wattage your AC uses may
also go up. Look at the voltage readings when the watts are low and
compare it to the voltage when when the wattage use is higher. One
thing you can do the help your AC unit is the (gently) use your water
hose on a spray setting to wash the outside coil. A power stream will
bend the fins on the condenser so be careful. You can do it while it's
running without a problem as long as you don't direct a direct stream
at the electrical covers through the side vents where you can rinse out
the inside of your window unit.

TDD

On Jul 12, 8:37*pm, Gz wrote:
On Jul 12, 2:50*pm, jamesgangnc wrote:





On Jul 12, 2:09*pm, kansascats wrote:

I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

It's been suggested and disproved that shading the outside half of ac
has any notoicable effect. *What you are seeing is the reduced
transfer rate of heat to the atmosphere because of the increased
outside air temp. *This raises the high side pressure and makes the
compressor work harder.

Bottom line it's not the sun beating down on it. *It's the higher air
temp.

You might think shading the unit has no effect, but it does. The
biggest thing is the whole wall in the sun. The brick or siding really
heats up the whole intake area.

You need to shade the whole wall.

Greg- Hide quoted text -

- Show quoted text -

I suggest you do some more research. Shading the unit makes no
difference. The factor is the ambient air temp around the unit.
Shading the entire area might lower that temp a degree or two from the
nearby air temp in the sun but short of planting trees and waiting 10
years there's no way to do that. And 1 or 2 degrees is not going to
make much difference.

On Jul 13, 7:39*am, jamesgangnc wrote:
On Jul 12, 8:37*pm, Gz wrote:





On Jul 12, 2:50*pm, jamesgangnc wrote:

On Jul 12, 2:09*pm, kansascats wrote:

I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

It's been suggested and disproved that shading the outside half of ac
has any notoicable effect. *What you are seeing is the reduced
transfer rate of heat to the atmosphere because of the increased
outside air temp. *This raises the high side pressure and makes the
compressor work harder.

Bottom line it's not the sun beating down on it. *It's the higher air
temp.

You might think shading the unit has no effect, but it does. The
biggest thing is the whole wall in the sun. The brick or siding really
heats up the whole intake area.

You need to shade the whole wall.

Greg- Hide quoted text -

- Show quoted text -

I suggest you do some more research. *Shading the unit makes no
difference. *The factor is the ambient air temp around the unit.
Shading the entire area might lower that temp a degree or two from the
nearby air temp in the sun but short of planting trees and waiting 10
years there's no way to do that. *And 1 or 2 degrees is not going to
make much difference.- Hide quoted text -

- Show quoted text -

Do you have research that shows direct sun on a window unit has
no effect? If direct sun on a window can add heat to a room, one
would think that same heat applied to both the window and a
window unit AC would have an effect.

I've seen some studies done with CENTRAL AC, where shading
the CONDENSER made no material difference because as you
say, it's the air temp that counts. But I have not seen the same
for window units and for obvious reasons I don't believe the results
for split systems can be applied to self-contained window units.

kansascats wrote:

We are around 97F outside now -- cooling to 78F inside.

Sounds like your A/C unit is too small for the area you are trying to cool.
It shouldn't have to run constantly in order to keep the cooled area at 72.

Jon

On Jul 13, 8:16*am, "Jon Danniken"
wrote:
kansascats wrote:

We are around 97F outside now -- cooling to 78F inside.

Sounds like your A/C unit is too small for the area you are trying to cool.
It shouldn't have to run constantly in order to keep the cooled area at 72.

Jon

A properly sized ac will run pretty much continuously when the temp is
in the high 90s. A larger unit would not run enough during more
moderate outdoor temps resulting in high indoor humidity making it
feel clammy. You want a unit that is just big enough to hande the
area but not bigger. It's perfectly normal to size one such that it
can't keep up when the outdoor temp is unusually high. And the wear
on them is actually less if they run for longer periods rather than
startng and stopping a lot. Startup is hard on the compressors
because they start in a loaded condition, the refrigerant is already
near or above 100 psi when not running.

On Jul 12, 1:09*pm, kansascats wrote:
I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

I would think voltagw is dropping or the compressor is failing, how
old is it

On Jul 13, 8:57*am, ransley wrote:
On Jul 12, 1:09*pm, kansascats wrote:

I plugged my window AC into a "killawatt". *It was running 900 watts,
then the past few days it's been climbing to 1000, then 1100, even
1200 as the day wears on -- and the sun beats down on the unit to the
west side.

Suppose shading this could make a big (300 w) difference?

I would think voltagw is dropping or the compressor is failing, how
old is it

Clearly all of you know nothing about air conditioning. Go ask any
hvac tech about the refrigerant pressures and compressor current draw
as the outside air temp goes from 70 to 100.

Shading the house to reduce the heating effect on the house can make a
difference. Shading the unit will make no appreciable difference. If
you don't believe me go get one of those killawatt meters and try it
yourself.

Watts is a unit of work. If the voltage drops, it should be
same watts, over all.

And the OP is testing at different times of the same day, so
compressor wear is negligible.

I suspect the difference is the outdoor air temp.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"ransley" wrote in message
...
On Jul 12, 1:09 pm, kansascats wrote:
I plugged my window AC into a "killawatt". It was running
900 watts,
then the past few days it's been climbing to 1000, then
1100, even
1200 as the day wears on -- and the sun beats down on the
unit to the
west side.

Suppose shading this could make a big (300 w) difference?

I would think voltagw is dropping or the compressor is
failing, how
old is it

wrote
Do you have research that shows direct sun on a window unit has
no effect? If direct sun on a window can add heat to a room, one
would think that same heat applied to both the window and a
window unit AC would have an effect.

I've seen some studies done with CENTRAL AC, where shading
the CONDENSER made no material difference because as you
say, it's the air temp that counts. But I have not seen the same
for window units and for obvious reasons I don't believe the results
for split systems can be applied to self-contained window units.

Why would it not apply? A window unit is sort of a mini-mini split.
Everything is in one big box instead of split apart by a piece of copper
tubing. The condenser coil is covered with sheet metal and has a fan
blowing on I it, just like a big unit. The fan sucks in air from the side
vent, blows it across the coil.

What may be different is the slinger ring on the fan. That can affect the
operating temperature. If the air is very dry, there will be little
condensate for the fan to sling onto the coil. Does that make a difference
in the readings the OP is getting? I don't really know. Easy enough to
test though, by spraying some water into the vents while it is operating.
It may reduce the pressures in the system and lessen the motor load of the
compressor.

Some other info...

The outdoor air is very humid here.. 20% min to 80s in the AM/PM

The indoor air is quite comfortable to me at 80F -- I'm assuming
because it's pulling so much moisture out of the air. It can keep up
just fine for the 12x24x8H space it's intended to cool. Every once in
awhile I open the door to another 24x24 area and it even does a decent
job of lowering the humidity such that I can do my woodworking over
there. (I really need to poke another one of these in the wall on
that side, but for now it does the job).

When the compressor runs it draws 950 to 1250 watts.
Right now it's about 88F outside and drawing 1017 watts, and climbs up
a bit as it runs during that cycle.
When it was close to 100F, the draw was around 1250

The unit is probably 6 years old.

On Jul 13, 7:26*am, jamesgangnc wrote:
On Jul 13, 8:16*am, "Jon Danniken"

wrote:
kansascats wrote:

We are around 97F outside now -- cooling to 78F inside.

Sounds like your A/C unit is too small for the area you are trying to cool.
It shouldn't have to run constantly in order to keep the cooled area at 72.

Jon

A properly sized ac will run pretty much continuously when the temp is
in the high 90s. *A larger unit would not run enough during more
moderate outdoor temps resulting in high indoor humidity making it
feel clammy. *You want a unit that is just big enough to hande the
area but not bigger. *It's perfectly normal to size one such that it
can't keep up when the outdoor temp is unusually high. *And the wear
on them is actually less if they run for longer periods rather than
startng and stopping a lot. *Startup is hard on the compressors
because they start in a loaded condition, the refrigerant is already
near or above 100 psi when not running.

Insightful reply - thank you. I never thought much about that. Many
talk about being able to cool-down a room quickly, but the logic you
supplied makes sense. Our house central AC does nearly run all the
time when it's in the upper 90s. In fact on some days when the wife
is cooking the temp is a few degrees about the desired temp -- it just
cannot keep up. I replaced the fillter just to be sure, but I think
it's just at it's max for the above average outdoor temp.

On 7/28/2011 1:45 PM, kansascats wrote:
On Jul 13, 7:26 am, wrote:
On Jul 13, 8:16 am, "Jon Danniken"

wrote:
kansascats wrote:

We are around 97F outside now -- cooling to 78F inside.

Sounds like your A/C unit is too small for the area you are trying to cool.
It shouldn't have to run constantly in order to keep the cooled area at 72.

Jon

A properly sized ac will run pretty much continuously when the temp is
in the high 90s. A larger unit would not run enough during more
moderate outdoor temps resulting in high indoor humidity making it
feel clammy. You want a unit that is just big enough to hande the
area but not bigger. It's perfectly normal to size one such that it
can't keep up when the outdoor temp is unusually high. And the wear
on them is actually less if they run for longer periods rather than
startng and stopping a lot. Startup is hard on the compressors
because they start in a loaded condition, the refrigerant is already
near or above 100 psi when not running.

Insightful reply - thank you. I never thought much about that. Many
talk about being able to cool-down a room quickly, but the logic you
supplied makes sense. Our house central AC does nearly run all the
time when it's in the upper 90s. In fact on some days when the wife
is cooking the temp is a few degrees about the desired temp -- it just
cannot keep up. I replaced the fillter just to be sure, but I think
it's just at it's max for the above average outdoor temp.
And, yes it IS normal for the power to change with temperature. Also,
that's what nice about the new 2 stage AC units. I have a 2 stage
central unit and as the temperature doesn't usually get real high at
2500' up in the mountains, it usually only runs on stage 1. So it runs
longer and takes out more humidity. I also have a Honeywell thermostat
that will over run the AC in order to reach a settable humidity level.
It works extremely well. The only time I have seen it go into stage 2
is when you manually set the thermostat to a lower value or the
thermostat changes the temperature due to the program.