If I use my airco at night and set the temperature at let's say at 27 degrees, why if it is OUTSIDE colder than 27 degrees the aircon will not use the air from outside to cool your room?

 

Understand we need to 'modify' the airco as it can't use air from outside now but it would save a lot of energy I think...

 

 

 

Because it is designed to intake air from the inside.  Imagine if there was an outside air intake:  that would need another hole in the wall and another place for bugs to enter, notwithstanding that the outside air temperature is usually warmer than the conditioned inside.

Opening the window would achieve a similar effect at a lower cost.

 

56 minutes ago, bankruatsteve said:

Because it is designed to intake air from the inside.  Imagine if there was an outside air intake:  that would need another hole in the wall and another place for bugs to enter, notwithstanding that the outside air temperature is usually warmer than the conditioned inside.

An 'extra' hole in your wall - if it saves energy - should not be a problem I think.

 

I noticed the opposite (depends on where you live in thailand of course) - many time it's colder outside my house than inside BUT the problem is that the walls of my house are so ^&%$* hot because of the sun that I need an aircon to lower the temp in my room while the outside air is cold enough ....

37 minutes ago, Crossy said:

Opening the window would achieve a similar effect at a lower cost.

 

Agree, but I have mosquito windows and curtains in front of my windows (because of the street lights) so I need 'forced' cooling, if I open my window nothing will happen in my room...

8 minutes ago, Cloggie said:

An 'extra' hole in your wall - if it saves energy - should not be a problem I think.

 

I noticed the opposite (depends on where you live in thailand of course) - many time it's colder outside my house than inside BUT the problem is that the walls of my house are so ^&%$* hot because of the sun that I need an aircon to lower the temp in my room while the outside air is cold enough ....

That's why most (?) new homes will use the ALC blocks as they do not absorb heat from the sun.  Shading from trees and/or painting with a premium grade paint will help but you might be surprised at the cool air that will dump in even with the drapes.  It would also help to set up an exhaust fan somewhere else (even a normal fan set in an open window) which will draw in the outside air.  

good drapes and a solid front door have lowered our internal temp quite a bit. However, my study, which gets the sun all day on the outside walls, is a nightmare to cool.  Takes two air cons at high setting to make any impact. 

29 minutes ago, bankruatsteve said:

It would also help to set up an exhaust fan somewhere else (even a normal fan set in an open window) which will draw in the outside air.  

Beat me to it, cheap and simple solution.

 

There are aircons that can take outside air, but they tend to be those awful window units.

 

If you can shade your outside walls (plants, trees) that can make a massive difference.

 

1 hour ago, Crossy said:

There are aircons that can take outside air, but they tend to be those awful window units.

back in the 70s "National" (Panasonic) produced split units which had the option to suck about 10-15% of the fan capacity from outside. disadvantage was no possibility to shut off as is the case with wall/window units.

1 hour ago, Cloggie said:

An 'extra' hole in your wall - if it saves energy - should not be a problem I think.

 

I noticed the opposite (depends on where you live in thailand of course) - many time it's colder outside my house than inside BUT the problem is that the walls of my house are so ^&%$* hot because of the sun that I need an aircon to lower the temp in my room while the outside air is cold enough ....

you need to install a "whole-house-fan". use the search function, several threads exist. our home is cooled down and aired (with few exceptions) every day by a huge fan running from 0500 till 0700.

besides the big fan i installed in all rooms small manually operated exhaust fans.

 

2 hours ago, Cloggie said:

Agree, but I have mosquito windows and curtains in front of my windows (because of the street lights) so I need 'forced' cooling, if I open my window nothing will happen in my room...

take it from me and he who knows        it will work

4 hours ago, Cloggie said:

why if it is OUTSIDE colder than 27 degrees the aircon will not use the air from outside to cool your room?

Are we talking 'centralized HVAC' (air exchange) or 'AirCon' (heat exchange/dehumidifier).

I see these as two very different things.

 

 

 

Example, last night temperature in my room 30 degrees, temperature outside 25 degrees. Opened the windows for a couple of hours (with mosquito windows closed) no result, still 30 degrees so had the switch the airco on again.

On 10/29/2017 at 7:58 PM, RichCor said:

Are we talking 'centralized HVAC' (air exchange) or 'AirCon' (heat exchange/dehumidifier).

I see these as two very different things.

 

 

 

I am talking about a room air-conditioner - Mitsubishi SRK19CES and a SRK25CES

On 10/29/2017 at 6:21 PM, Naam said:

you need to install a "whole-house-fan". use the search function, several threads exist. our home is cooled down and aired (with few exceptions) every day by a huge fan running from 0500 till 0700.

besides the big fan i installed in all rooms small manually operated exhaust fans.

 

If I ever build my own house, I will certainly have a look at this a 'whole-house-fan' - but a bit difficult if you rent.....

17 minutes ago, Cloggie said:

Example, last night temperature in my room 30 degrees, temperature outside 25 degrees. Opened the windows for a couple of hours (with mosquito windows closed) no result, still 30 degrees so had the switch the airco on again.

If you haven't tried already... open a window in a different room and keep your bedroom door open.

On 10/29/2017 at 6:41 PM, Lamkyong said:

take it from me and he who knows        it will work

Cloggie is right. it does NOT work. period!

22 hours ago, Cloggie said:

Example, last night temperature in my room 30 degrees, temperature outside 25 degrees. Opened the windows for a couple of hours (with mosquito windows closed) no result, still 30 degrees so had the switch the airco on again.

 

As you have curtains that is not surprising. You need a free flow of air and, preferably, a cross-flow of air. In my condo I can open two doors and close two mosquito screens and get a strong cross-flow of air (sometimes more like a gale than a flow). At times when the outside temperature is low (ie like the last couple of days, or in Jan/Feb) this can be more than adequate and the aircon is not needed.

 

Another solution, much cheaper than the whole-house ventilation system suggested, would be to place a stand fan by one open window in order to increase the exchange of air with outside.

 

Of course a whole-house forced ventilation system is very nice if you care to pay for it.

>> Another solution, much cheaper than the whole-house ventilation system suggested, would be to place a stand fan by one open window in order to increase the exchange of air with outside.

 

Will try that tonight, never thought about that!

3 minutes ago, Cloggie said:

>> Another solution, much cheaper than the whole-house ventilation system suggested, would be to place a stand fan by one open window in order to increase the exchange of air with outside.

 

Will try that tonight, never thought about that!

 

In Europe, before I put air-con in, we had just one very tall narrow window in each bedroom. I found that putting a stand-fan near the bottom of the window, blowing inwards, did the trick. The hotter air at the top of the room would naturally leave via the top of the window.

If you have two windows and can get a cross-flow going then it will work better and you should just make sure that your fan is blowing in the natural wind direction, of course.

 

Mosquito screens will obviously reduce the effectiveness of this somewhat, but it should still do the trick.

in California we had a neighbor with a hot, stuffy little studio apartment and he arranged a large fan in a window in exhaust position (suction from the room) and it did the trick, very comfortable...

 

but that was in southern California where the air is dry...most of the function of AC in subtropical climates is humidity control and to exhaust humid inside air to replace with humid outside air with a fan might not be as effective even if the outside air is at a lower temperature...

 

rather than languish in the oppressive local ambient conditions I put on the AC and switch on the ceiling fan to circulate the colder air and then get under the duvet and zzzzz...