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  #1   Report Post  
tom
 
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Default Efficient use of Air conditioner

Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom
  #2   Report Post  
micheal
 
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"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom


1 - this depends upon the temperature Vs time profile, A and B are good
strategies with certain profiles.
you also need the humidity levels/profile, as air that is cooler but has a
lot of moister causes the AC to run longer to remove the water. If you have
30% humidity, widows open, 80%, windows closed. Look up latent heat.
2.- Method A. Get that superheated air out (140F) and start with 80F


  #3   Report Post  
Pyriform
 
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Default Efficient use of Air conditioner

micheal wrote:
"tom" wrote in message
2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?


2.- Method A. Get that superheated air out (140F) and start with 80F


Modified method A: Start the AC at the same time as you open the
windows. The system will take a few moments to start producing cool air,
so you might as well have it do the pre-cooling in parallel. Won't make
much difference to the energy cost, and the total time to a cool car
will be less.

After you've closed the windows, set the AC to recirculate for a while
until the car has reached a comfortable temperature. Some climate
control systems do this automatically.




  #4   Report Post  
DHatheway
 
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Default Efficient use of Air conditioner

"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom


Method A is probably going to be moer efficient in both cases.

So what? The energy and money you save doing it your way would not offset
the cost of a divorce. Do it your wife's way whenever she's around.


  #5   Report Post  
greywolf42
 
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Default Efficient use of Air conditioner

tom wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?


If there is no wind (or no fan blowing the cool air into your house), then
neither method A nor method B will cool the house down more quickly. This
is because the air return to the AC system is inside the house. The hot air
will not get 'blown out' of the house. And there will be minimal air
exchange through the windows.

As the wind increases, eventually method A will cool the house down more
quickly. However, it will take a good sized wind or big windows to beat the
AC. AC units typically cool the air about 20 degrees F. So the air coming
out of the AC will be at 61 F (starting with 81 F), regardless of where the
thermostat is set.

(Let your wife win on this one.)

If you want to save electricity, buy a window fan.


2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?


Method A here will cool the air inside the car faster. But the main source
of heat in the car is not the air, but the roof, seats, floor, windows and
dashboard. They've all been heated to uncomfortable levels, and the heat
capacity of the air is minimal, compared to the rest.

Once the air has been blown out (which will take about 2 seconds), you can
safely close the windows.

There is no electricity in a car AC system (except in an electric car)...
the AC compressor runs off of an engine belt.

--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}





  #6   Report Post  
Brigitte
 
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"DHatheway" wrote in message
...
"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom


Method A is probably going to be moer efficient in both cases.

So what? The energy and money you save doing it your way would not offset
the cost of a divorce. Do it your wife's way whenever she's around.


So true! Don't waste your time and energy on this trivial crap.

Brigitte


  #7   Report Post  
Joseph Meehan
 
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Default Efficient use of Air conditioner

tom wrote:
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?


There are far too many variables to say one or the other.

I will say the one thing many people miss when they try to figure this
out is the very high cost of removing the moisture that comes in from
outside.

However I do have an answer. Real time test! Try it both ways several
times. See what works best (more comfortable and less run time) Repeat
several times on different days. Keep records and let us know the answer.
(Local weather may provide degree days so you can adjust for different
outside temps to some degree.


2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?


Most cars burn gas not electricity. ;-)

Generally I would guess opening the windows for the first quarter mile
to exchange the hot inside air, then shutting it up. There have been a
number of test that indicate that cars with A/C get better mileage using the
A/C than by opening the windows because of all the wind resistance added by
the open windows.


Thanks!

-Tom



--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math



  #8   Report Post  
 
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Default Efficient use of Air conditioner

Joseph Meehan wrote

...the very high cost of removing the moisture that comes in from outside.


That's a low cost, unless water vapor condenses inside the house.

Nick

  #9   Report Post  
HeatMan
 
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Default Efficient use of Air conditioner


"DHatheway" wrote in message
...
"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom


Method A is probably going to be moer efficient in both cases.

So what? The energy and money you save doing it your way would not offset
the cost of a divorce. Do it your wife's way whenever she's around.


It also has to do with air filtration.


  #10   Report Post  
Doug Kanter
 
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Default Efficient use of Air conditioner

"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:


You must be young. You will soon learn that with regard to climate control,
women are completely out of their minds. There's simply no point in arguing.
If she wants to waste money doing the wrong thing, let her.

In my wing of my office building, there are 3 small offices, one of which is
mine. Three separate tenants, in other words. The thermostat is in the
office next door. Three women work in that office, ranging in age from 30 to
60. At almost any time of year, I couldn't figure out how to dress
comfortably because of the huge temperature swings. It got to the point
where I brought in a recording thermometer that I use around the garden. In
any 8 hour day, the temp would vary as much as 20 degrees. The ladies
thought this was funny. Finally, the landlord put a locked box over the
thermostat and set it for 72. The ladies swore the temp was all over the
place, so the landlord brought in a digital recording thermometer. (Big
office park, well equipped). It showed a temp range of about 2 degrees
either side of 72. End of problem.

Just give up.




  #12   Report Post  
TURTLE
 
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This is Turtle.

Reply split in parts


"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?


What Price do you set on your Happiness ? That will be the Price you'll pay for
having it your way or not choosing Method B.



2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?


What Price do you set on having a enjoyful Drive everywhere you may go ? That
will be the price you will pay for not choosing Method B.


Thanks!

-Tom


Now you have a choice here by Choosing Method B and have a enjoyful life or
Choosing Method A and Paying the Ultimate Price on Happiness the rest of your
life. I even think your going to pay the Ultima price even asking this question.

TURTLE


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.714 / Virus Database: 470 - Release Date: 7/2/2004


  #13   Report Post  
TURTLE
 
Posts: n/a
Default Efficient use of Air conditioner


"HeatMan" wrote in message
nk.net...

"DHatheway" wrote in message
...
"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom


Method A is probably going to be moer efficient in both cases.

So what? The energy and money you save doing it your way would not offset
the cost of a divorce. Do it your wife's way whenever she's around.


It also has to do with air filtration.


This is Turtle.

Would that filter be for the **** coming his way also ?

TURTLE


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.714 / Virus Database: 470 - Release Date: 7/2/2004


  #14   Report Post  
CBHVAC
 
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Default Efficient use of Air conditioner


"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?



PROBABLY B.

What you say? Simple..opening the windows will remove some of the warm air,
but unless you have a whole house fan pulling like hell, you wont be able to
use all that cool air out, and you still have latent heat in the walls,
floors, ceiling...furniture...etc..

But my queston is....why are you allowing your air in the home to reach 81F?
Set your thermostat and forget it...its cheaper that way..



2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's


Again...depends. Personally, my personal work van for example, has these
neat little vents in the taillights...fire the AC up, open they go, and out
goes the hot air....
And even when I was in CA,I didnt worry about that stuff...I just went on
with it...


Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom



  #16   Report Post  
 
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Default Efficient use of Air conditioner

CBHVAC wrote:

"tom" wrote:


1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?


PROBABLY B.

What you say? Simple..opening the windows will remove some of the warm air,
but unless you have a whole house fan pulling like hell, you wont be able to
use all that cool air out, and you still have latent heat in the walls,
floors, ceiling...furniture...etc..


Why latent heat, ie condensation?

But my queston is....why are you allowing your air in the home to reach 81F?
Set your thermostat and forget it...its cheaper that way..


Newton was wrong? :-)

Nick

  #18   Report Post  
tom
 
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Guys, Thanks a million for your answers and advices! It's nothing
about how to save more money. I just meant to remind my wife "hey, I'm
not that stupid, you forgot?" This is kind of once-a-year event. Last
time we argued about the pronunciation of a word. It was 16 months ago
and loser would be slapped (she proposed that) After we looked it up
in our dictionary, she ran away quickly.
  #19   Report Post  
 
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Default Efficient use of Air conditioner

wrote

...the very high cost of removing the moisture that comes in from outside.


That's a low cost, unless water vapor condenses inside the house.


And just why do you think air conditioners have drip pans?


To remove liquid water from walls and furniture? :-)

Nick

  #20   Report Post  
Doug Kanter
 
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"tom" wrote in message
om...
Guys, Thanks a million for your answers and advices! It's nothing
about how to save more money. I just meant to remind my wife "hey, I'm
not that stupid, you forgot?" This is kind of once-a-year event. Last
time we argued about the pronunciation of a word. It was 16 months ago
and loser would be slapped (she proposed that) After we looked it up
in our dictionary, she ran away quickly.


The loser would be slapped? Unless she meant you could spank her, you better
get the hell out of there quick, buddy. Next thing you know, she'll be
proposing dueling with hatchets.




  #24   Report Post  
v
 
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On 20 Jul 2004 07:28:37 -0700, someone wrote:


-Tom


So what will you do with our answers? Do you think you would really
accomplish anything showing them to her? Does what anonymous
strangers say "prove" anything?

Do you really think you can "win" an argument with your spouse?

-v.
  #25   Report Post  
Doug Kanter
 
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Default Efficient use of Air conditioner


"v" wrote in message
...
On 20 Jul 2004 07:28:37 -0700, someone wrote:


-Tom


So what will you do with our answers? Do you think you would really
accomplish anything showing them to her? Does what anonymous
strangers say "prove" anything?

Do you really think you can "win" an argument with your spouse?

-v.


Actually, all these answers might help, but for a sick reason. Some people
insist on seeing things in writing, and they're satisfied even if the
writers are rank amateurs. My ex was that way. Couldn't trust her own
observations.




  #26   Report Post  
Edwin Pawlowski
 
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wrote in message
The best use of a house A/C is to use it with a fan. Nobody
believes me when I say that I cool my house with a 5000 BTU
A/C and two fans.


Add me to the list. Unless you have a very small house and moderate
climate, that small of a unit will do very little. I agree a fan can help
immensely with air circulation, you still need a certain amount of capacity
to move a given heat load.

If you have a two room cabin, OK, if you have a 2,000 sq. ft. Colonial, you
are full of BS.


  #28   Report Post  
 
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In article ,
"Edwin Pawlowski" wrote:

wrote in message
The best use of a house A/C is to use it with a fan. Nobody
believes me when I say that I cool my house with a 5000 BTU
A/C and two fans.


Add me to the list.


Ah, well. :-)

.. Unless you have a very small house and moderate
climate, that small of a unit will do very little.


I think most people would consider the house small. However,
I also know about arranging tree shade, insulation, and do not
need the house to be 65 degrees for comfort. 65 is too cold.
If I can get the house cooled down below 70 at night, I don't need
the A/C to be on at all. I simply shut the windows to keep the
heat out and run a fan for circulation. The house doesn't
get hot until ~17:00. By then it's usually cool enough outside
to cool the house.


...I agree a fan can help
immensely with air circulation, you still need a certain amount of

capacity
to move a given heat load.


Nah. All you have to do is move the hot air into the room that
has the A/C. Voila! Cool house. It helps for that room to have
two doors going into two rooms that eventually connect with each
other. The rooms aren't configured like spokes in a wheel without
a rim.

If you have a two room cabin, OK, if you have a 2,000 sq. ft. Colonial,

you
are full of BS.


The only thing you have to do is cool the one room, then move the cooled
air out and the warmer air in.

/BAH

Subtract a hundred and four for e-mail.
  #29   Report Post  
Richard Henry
 
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wrote in message
...
In article ,
"Edwin Pawlowski" wrote:

wrote in message
The best use of a house A/C is to use it with a fan. Nobody
believes me when I say that I cool my house with a 5000 BTU
A/C and two fans.


Add me to the list.


Ah, well. :-)

.. Unless you have a very small house and moderate
climate, that small of a unit will do very little.


I think most people would consider the house small. However,
I also know about arranging tree shade, insulation, and do not
need the house to be 65 degrees for comfort. 65 is too cold.
If I can get the house cooled down below 70 at night, I don't need
the A/C to be on at all. I simply shut the windows to keep the
heat out and run a fan for circulation. The house doesn't
get hot until ~17:00. By then it's usually cool enough outside
to cool the house.


How do I "arrange tree shade"? Trees in big planters on wheels?

...I agree a fan can help
immensely with air circulation, you still need a certain amount of

capacity
to move a given heat load.


Nah. All you have to do is move the hot air into the room that
has the A/C. Voila! Cool house. It helps for that room to have
two doors going into two rooms that eventually connect with each
other. The rooms aren't configured like spokes in a wheel without
a rim.

If you have a two room cabin, OK, if you have a 2,000 sq. ft. Colonial,

you
are full of BS.


The only thing you have to do is cool the one room, then move the cooled
air out and the warmer air in.


In San Diego, it has been pretty hot, but not too humid, the last few days.
We have survived without A/C by running oscillating fans indoors and seeking
shade/breeze locations outdoors (except for my retaining-wall project, which
is on an unshaded south-facing hill). Upstairs we keep a fan in the
south-facing window and a ceiling fan running all the time in the master
bedroom. My son's room faces east - a window fan turned on after dark makes
that room comparitively frigid.

If things get really bad, we drive down to the grocery store and stand in
front of the meat cooler.



  #30   Report Post  
 
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In article 5TMLc.28901$9I.20458@okepread02,
"Richard Henry" wrote:

wrote in message
...

snip

.. Unless you have a very small house and moderate
climate, that small of a unit will do very little.


I think most people would consider the house small. However,
I also know about arranging tree shade, insulation, and do not
need the house to be 65 degrees for comfort. 65 is too cold.
If I can get the house cooled down below 70 at night, I don't need
the A/C to be on at all. I simply shut the windows to keep the
heat out and run a fan for circulation. The house doesn't
get hot until ~17:00. By then it's usually cool enough outside
to cool the house.


How do I "arrange tree shade"? Trees in big planters on wheels?


You can. Awnings or shutters help. Shutters are neat in that
you can shut out the sunlight and keep the airflow going. Curtains
block air flow. I'd have to see the layout of your yard and
house to tell if growing stuff would help.

snip

The only thing you have to do is cool the one room, then move the cooled
air out and the warmer air in.


In San Diego, it has been pretty hot, but not too humid,
the last few days.
We have survived without A/C by running oscillating
fans indoors and seeking
shade/breeze locations outdoors (except for my
retaining-wall project, which
is on an unshaded south-facing hill).


That wall will absorb and the emit heat. A good thing
in winter, but not desired in summer. Shading it with
plants that deleaf in the winter is one way to arrange
shade.

...Upstairs we keep a fan in the
south-facing window and a ceiling fan running all the time in the master
bedroom. My son's room faces east - a window fan
turned on after dark makes
that room comparitively frigid.


I cool the house down by placing a fan facing out and running
it. If you have an attic fan, then you want to place the
first floor fans facing in but only run them that way when
it's cooler outside than inside. During the heat of the day,
shut the windows or leave a couple strategically placed windows
open a crack for oxygen. Then run fans that circulate the air
inside only, in a down to up direction.


If things get really bad, we drive down to the grocery store and stand in
front of the meat cooler.


I put on my winter woolies before I walk in the grocery store.
It's ****ing freezing in those stores...but not as cold as
the post office. There is no mystery about why those people
go postal; their brains get frozen to the point of no possible
electrical activity. I want to put on a wool face mask when
I walk into those buildings.

/BAH

Subtract a hundred and four for e-mail.


  #31   Report Post  
 
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wrote:

Joseph Meehan wrote


...the very high cost of removing the moisture that comes in from outside.


That's a low cost, unless water vapor condenses inside the house.


We were talking about a) ventilating a house at night vs b) keeping an AC
running. I'm thinking a) is better, as long as we don't have condensation
inside the house.

Take a given volume of air at 90 F and 40%.


Why 90 F and 40%?

How much energy does it take to cool the air to say 72 F?


Depends on the volume :-)

How much energy does it take to cool and condense enough water to get down
to 40% at 72 F?


Why 40%? Standard ASHRAE humans are comfy at 56% and 80.2 F.

...Without running through the math, I would think getting the water vapor
out is the energy expensive part.


Try math! If your 32x32x8' house has 6K Btu/F of fast capacitance and 400
Btu/h-F of thermal conductance, including 200 cfm of air leaks, and it's
78% and 71 F in the morning, and the outdoor temp hits 92 in the afternoon,
with the morning humidity ratio, which is better, a) or b)?

Nick

  #32   Report Post  
tflfb
 
Posts: n/a
Default Efficient use of Air conditioner

Turn on a/c in house and leave it on.

Tom
"tom" wrote in message
om...
Can not convince wife about two things. Just want to bring it here for
a serious judgement:

1. Use Air conditioner for home at night:
Temperature outside = 69F, Temp in home = 81F,
Air conditioner trigger set to 75F

method A. With windows being open - My way
method B. With windows being closed - Wife's way

Question: which one make house temp drop faster and which one costs
less electricity?

2. Use AC for car in a hot summer day
Temperature outside = 80F,
Temp of a car parked in sun for one hour = very hot, don't know
exact temp

After getting into the car
Method A: open windows, drive for a moment then close the windows
and start AC. - mine
Method B: Start AC right away without opening windows. - wife's

Question: which one make car temp drop faster and which one costs
less electricity?

Thanks!

-Tom



  #35   Report Post  
Wayne
 
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Default Efficient use of Air conditioner

wrote in :

In article 5TMLc.28901$9I.20458@okepread02,
"Richard Henry" wrote:

wrote in message
...

snip

.. Unless you have a very small house and moderate
climate, that small of a unit will do very little.

I think most people would consider the house small. However,
I also know about arranging tree shade, insulation, and do not
need the house to be 65 degrees for comfort. 65 is too cold.
If I can get the house cooled down below 70 at night, I don't need
the A/C to be on at all. I simply shut the windows to keep the
heat out and run a fan for circulation. The house doesn't
get hot until ~17:00. By then it's usually cool enough outside
to cool the house.


How do I "arrange tree shade"? Trees in big planters on wheels?


You can. Awnings or shutters help. Shutters are neat in that
you can shut out the sunlight and keep the airflow going. Curtains
block air flow. I'd have to see the layout of your yard and
house to tell if growing stuff would help.

snip


Most of your suggestions are helpful but they are not a solution to the
heat of the desert Southwest. Shade helps, of course, but when the
"cool" night air is 95-100 degrees, the only things that bring relief are
swamp coolers and a/c.


The only thing you have to do is cool the one room, then move the
cooled air out and the warmer air in.


That won't cut it.

In San Diego, it has been pretty hot, but not too humid,
the last few days.
We have survived without A/C by running oscillating
fans indoors and seeking
shade/breeze locations outdoors (except for my
retaining-wall project, which
is on an unshaded south-facing hill).


That wall will absorb and the emit heat. A good thing
in winter, but not desired in summer. Shading it with
plants that deleaf in the winter is one way to arrange
shade.

...Upstairs we keep a fan in the
south-facing window and a ceiling fan running all the time in the
master bedroom. My son's room faces east - a window fan
turned on after dark makes
that room comparitively frigid.


I cool the house down by placing a fan facing out and running
it. If you have an attic fan, then you want to place the
first floor fans facing in but only run them that way when
it's cooler outside than inside. During the heat of the day,
shut the windows or leave a couple strategically placed windows
open a crack for oxygen. Then run fans that circulate the air
inside only, in a down to up direction.


Fans, especially ceiling fans, certainly do help and allow you to
maintain a more evenly distributed temperature. The constant air
movement makes a slightly warmer temperature more tolerable. However, in
hot climates and without a/c, they only blow hot air. That's barely more
tolerable than nothing at all.



If things get really bad, we drive down to the grocery store and stand
in front of the meat cooler.


Now there's an option. I'll take my folding chair!


I put on my winter woolies before I walk in the grocery store.
It's ****ing freezing in those stores...but not as cold as
the post office. There is no mystery about why those people
go postal; their brains get frozen to the point of no possible
electrical activity. I want to put on a wool face mask when
I walk into those buildings.


You clearly don't require as much cooling as some people do. To me, it's
blessed relief to walk into a supercooled office or store.

A 5000 BTU a/c would barely keep a closet cool when the temp outside is
110-112 degrees F.

--
Wayne in Phoenix

If there's a nit to pick, some nitwit will pick it.


  #36   Report Post  
Timm Simpkins
 
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wrote in message
...
wrote:

Joseph Meehan wrote


...the very high cost of removing the moisture that comes in from

outside.

That's a low cost, unless water vapor condenses inside the house.


We were talking about a) ventilating a house at night vs b) keeping an AC
running. I'm thinking a) is better, as long as we don't have condensation
inside the house.

Take a given volume of air at 90 F and 40%.


Why 90 F and 40%?

How much energy does it take to cool the air to say 72 F?


Depends on the volume :-)

How much energy does it take to cool and condense enough water to get

down
to 40% at 72 F?


Why 40%? Standard ASHRAE humans are comfy at 56% and 80.2 F.

...Without running through the math, I would think getting the water

vapor
out is the energy expensive part.


Try math! If your 32x32x8' house has 6K Btu/F of fast capacitance and 400
Btu/h-F of thermal conductance, including 200 cfm of air leaks, and it's
78% and 71 F in the morning, and the outdoor temp hits 92 in the

afternoon,
with the morning humidity ratio, which is better, a) or b)?


If you walk out on your back porch and don't have enough pancakes to build a
fence True or False?

False because bicycles don't have hotdogs with flat sidewalks.


  #37   Report Post  
Timm Simpkins
 
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wrote in message
...
In article ,
"Edwin Pawlowski" wrote:

wrote in message
The best use of a house A/C is to use it with a fan. Nobody
believes me when I say that I cool my house with a 5000 BTU
A/C and two fans.


Add me to the list.


Ah, well. :-)

.. Unless you have a very small house and moderate
climate, that small of a unit will do very little.


I think most people would consider the house small. However,
I also know about arranging tree shade, insulation, and do not
need the house to be 65 degrees for comfort. 65 is too cold.
If I can get the house cooled down below 70 at night, I don't need
the A/C to be on at all. I simply shut the windows to keep the
heat out and run a fan for circulation. The house doesn't
get hot until ~17:00. By then it's usually cool enough outside
to cool the house.


Shutting the windows only works if no direct sunlight never hits the
windows. If it does, the temperature will increase faster inside the house
than it would with the windows open, especially if the floors are concrete.
It also depends on the thermal mass of your insulation. The higher the
thermal mass, the slower the walls are to change temperature. This is
usually a good thing where temperatures change above and below a desirable
temperature from day to night. It causes the temperature to somewhat
regulate inside. That's why underground is at a relatively constant
temperature.



...I agree a fan can help
immensely with air circulation, you still need a certain amount of

capacity
to move a given heat load.


Nah. All you have to do is move the hot air into the room that
has the A/C. Voila! Cool house. It helps for that room to have
two doors going into two rooms that eventually connect with each
other. The rooms aren't configured like spokes in a wheel without
a rim.

If you have a two room cabin, OK, if you have a 2,000 sq. ft. Colonial,

you
are full of BS.


The only thing you have to do is cool the one room, then move the cooled
air out and the warmer air in.

/BAH

Subtract a hundred and four for e-mail.



  #38   Report Post  
 
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In sci.physics wrote:
wrote:


Joseph Meehan wrote


...the very high cost of removing the moisture that comes in from outside.


That's a low cost, unless water vapor condenses inside the house.


We were talking about a) ventilating a house at night vs b) keeping an AC
running. I'm thinking a) is better, as long as we don't have condensation
inside the house.


Actually, it was the cost of getting water vapor out of the house that is
in contention.

Take a given volume of air at 90 F and 40%.


Why 90 F and 40%?


Because that's what it was when I wrote it.

It is called a sample problem.

How much energy does it take to cool the air to say 72 F?


Depends on the volume :-)


The volume was "given".

How much energy does it take to cool and condense enough water to get down
to 40% at 72 F?


Why 40%? Standard ASHRAE humans are comfy at 56% and 80.2 F.


It is a sample problem.

ASHRAE humans may be comfy at that, but over 40% is NOT comfy for me.

...Without running through the math, I would think getting the water vapor
out is the energy expensive part.


Try math! If your 32x32x8' house has 6K Btu/F of fast capacitance and 400
Btu/h-F of thermal conductance, including 200 cfm of air leaks, and it's
78% and 71 F in the morning, and the outdoor temp hits 92 in the afternoon,
with the morning humidity ratio, which is better, a) or b)?


If it got to 78%, I would move elsewhere.

--
Jim Pennino

Remove -spam-sux to reply.
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pjm@see_my_sig_for_address.com
 
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On Thu, 22 Jul 2004 13:06:54 -0600, "Timm Simpkins"
wrote:


wrote in message


If you walk out on your back porch and don't have enough pancakes to build a
fence True or False?

False because bicycles don't have hotdogs with flat sidewalks.


Nick's does - he built it himself. Damned thing won't roll,
but it's very efficient......





Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

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