Window AC placement, which is more efficient?


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Old 05-01-09, 10:53 PM
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Window AC placement, which is more efficient?

I attached a rough diagram of my living area and where the window AC is currently installed. It's a Sharp 10,500 BTU unit.




It's a long open space which makes it somewhat inefficient for cooling.

What we usually do is let that one big AC cool that entire area but I'm wondering if it would be better to buy two separate ~6,000 BTU units and place one by the living room window and one by the dining area. It takes a little while longer to get the dining area cooler. Would this be more efficient? Also, would the power consumption be much greater if I split the duties to two Air Conditioners?



The current Sharp unit is old and will be replaced. Interestingly, I bought one of those Kill-A-Watt meters and plugged the Sharp AC into it in. On high the Sharp was clocking in at around 600W. Now my brother gave me his used Samsung 12,400 BTU unit. I plugged it into the Kill-A-Watt meter briefly and I was getting a reading of 170W on high??? Can that be right?

Samsung SEER 9.8 12,500 btu
Sharp SEER (?) 10,500 btu
 
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Old 05-02-09, 12:16 PM
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Sure, wattage could be different due to age/efficiency, state of wear...
You could add a 1/2 ton unit in the dining area which would cool faster. Then the existing unit would run less. You'd try to synchronize the stats, and leave the smaller fan running, at least during the hottest time of the day for even temps.
Or you could install 2 6-8,000 btu units; new models would have a higher efficiency than the older unit. But go by the SEER rating, you get what you pay for...
Another approach is to run a 208/240 line and put a 1 ton or a little larger in one of the dining area windows. Then there would be a straight shot down the length of the whole room. The 240v unit would spin the meter 1/2 as fast, because it would draw 1/2 the amperage; which is what spins the meter.
Tom Beer 4U2
 
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Old 05-02-09, 04:40 PM
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wow, that is very helpful although i'm having some trouble following along.

When you say 1/2 ton you man add a very small 1,000 btu unit in the dining area? and leave a large one, like the samsung 12,000 btu in the living room area?

what is a 208/240 line? can you explain that a little bit further or maybe a link where i can read up on it? drawing less amperage, saving some energy costs would be fantastic.

i agree, you get what you pay for and i would buy the highest SEER i could find.
 
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Old 05-02-09, 04:47 PM
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AC is measured in BTU's 12,000 BTU's equals 1 Ton of cooling capacity so 6,000 BTU's equals 1/2 Ton
 
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Old 05-03-09, 01:50 PM
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Originally Posted by nocarsgo
what is a 208/240 line? can you explain that a little bit further or maybe a link where i can read up on it?
You will have one voltage or the other. Nothing you can do about it. Residences will have (to the best of my knowledge)240. 208 can be found in commercial settings where they are transformered off a 440 set-up there.

I work in a commercial building where there only is 440, 208, 177 and 120. No 240. Venders that come there that want 240 hookups are always concerned that 208 will wreck their motors or elements, until we reassure them that it will not.

For further, probably more detailed and scholarly discussion on this - you could ask about this question of yours in our very own electrical forum here. It's probably also come up before, also.
 
 

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