I live in a 2 bedroom, 2 bath duplex that is over at least 1100 sq. ft. The problem that I am having is during the summer months, I have my thermostat set at 76 degrees during the day and every room in the duplex gets cooled properly... except for the living room. It is the only room in the place that doesn't get near as cold as the others. Sometimes it gets so warm that I start to sweat and I am forced to turn on my fan just to get what cold air is entering the living room to circulate. I don't believe it is a dirty filter, because even with a new filter installed, it still doesn't quite get cooled as well as all the other rooms and I would think if it had anything to do with the system itself, it would affect the entire house and not just one room. Any tips or advice on what the problem might be or how I could correct it would be appreciated.

You did not mention any windows or which direction that room faced. In South Florida I had a livingroom with lots of windows that faced East and South. That room got hot and so did my bedroom which faced West and had lots of windows. The only thing that worked for me was putting window tint on the windows. That made the rooms much cooler and I also used heavy white insulated drapes which helped.

Are you getting enough air blown into the room by the a/c?

Circulation is key here. As twink sugested, sun shining in windows etc, will cuase a room to be warmer than others. Also the size of the room and how many registers it has plays a big part. If you have a ceiling fan, use it. The more you can circulate the air, the better the room will cool. Another thing is location of the thermostat. If the thermostat is in an area near a supply register, it will sense the temperature in that area, cuasing the thermostat to shut the system off before the living room has a chance to cool. You can try closing some for the registers in the rooms that get nice and cool. Just close them enough to where you get a little more airflo out of the registers in the living room. This is a simple way of "balancing" the systems airflo. Hope this helps, but its definitely hard to trouble shoot these problems without seeing the system and layout first hand..

well the problem with the duplex I live in is that it was built with single pane windows, so I know that has a lot to do with it. My living room has two of these windows, side by side, that are roughly 4 ft tall and 2.5 ft wide each. There are two registers in the room, both of them underneath the windows. The dimensions of the room are roughly 14.5 ft x 16 ft. with an 8 ft. ceiling, which comes out to around 1,856 cu. ft. give or take a few (if my math is correct). I have been thinking of buying the plastic wrap material (don't know the actual name) from Lowe's or Home Depot that you can put over your windows to help "seal" them and to help keep a little more air from getting out and coming in through the cracks. Seeing as how these single pane windows are pretty old, from the looks of them, I would think they have a few, maybe a lot, of leaks around the frames and the windows themselves. What are your takes on the plastic window wrap?

Are you able to check the duct work and make sure there are no leaks maybe blowing your much needed cool under the building instead of your room,,

Well I decided to switch my air filter yesterday to see if that might have anything to do with it. I was originally using the one month air filters at first, but switch to the 3 month "Purafilter" brand. Seeing as how that filter gets clogged up so easily, I think it might have been strangling my system. I went and got another 1 month filter yesterday and installed it and so far it seems to be cooling better in the living room, but it is only 83 degrees outside right now, so I won't know for sure if it is cooling better until it reaches the high 90's. With that said... if it was, in fact, the type of air filter all along, would a clogged up filter cause just one room to not cool properly? Or would it cause ALL the rooms to not cool properly?

Try caulking around the windows inside AND outside and using the drapes I suggested.

I have permanently sealed all my windows inside and outside, have heavy wooden shutters on the bottom and the top on allmy house windows. The heavy shutters in the closed position really reflect the sun and heat in the summer and the cold in the winter. But seeing shutters are a bit pricey a solution would not suggest it for you unless you own the place and not rent.

Also, try getting a good washable HEPA filter and use that. I bought one off EBAY custom sized and that lets MORE air through system than the throwaways ever did and also the Pureafilter did. That small change in itself helped out my system immensely. Bought it awhile ago but I'm sure you can find something similar. No, this is not one of those turquoise colored mesh wash filters you can buy at Walmart or Lowe's. This is a professional washable HEPA filter. Costs me around $60 but well worth it to contain all the dust, dirt, smoke, etc.

Here is a link to show you what kind of product I am talking about. I didn't buy my filter from them but they have something very similar

http://www.riteair.com/t-boair.aspx?...FQEKKgod4nfVXQ

Wow... did not know they even made non-powered, washable filters. The only ones I knew of were the "stick and twig" 1 month, the "Purafilter" type 3 month, and the electro-static filters that you have to wire into the system for power. I'm going to have to check them out. It seems as though the filter had a lot to do with the problem because today it reached around 90 degrees and the living room stayed relatively cool. The only reason I ruled out the filter at first was because I thought a clogged filter would affect the entire house and not just one room. Thanks for the advice on the filter. If anyone else reads this and has any more suggestions, feel free to leave them because I can use all the advice I can get to keep my electric bill down.