"What can I do to get this system to cool the house during the day short of rehauling the whole thing?"

- Do you have supply or return lines in the attic? If so, they could be drawing hot attic air into the system if there is a leaking return line in the attic, or you could be losing conditioned air if there is a supply line leaking in the attic.

- Check/add more attic insulation to the attic. Anything you can do to reduce heat transfer from the attic to the conditioned space is a plus.

- Keep blinds/curtains closed during the day.

- Make sure that your filter and evap coil (inside) are clean.

Go to the condenser out side next to the house. There are two copper lines exiting the back of the condenser. One line will be larger than the other and be covered with a foam insulation. The insulated line is the suction line, returning refrigerant from the cooling coil. This line should be cool to the touch and sweating if there is a lot of humidity in the air. The smaller, non insulated line is the liquid line, refrigerant from the condenser to the cooling coil, and should be slightly warm to the touch. If it's hot, your condenser needs cleaning.

Previous recommendations also apply about insulation, closed blinds, filters etc. this system is approaching the end of it's useful life, 15 to 20 years. It may just be shot!!

Air flow does not change with age unless some one has added on to the house or made duct modifications without good advise. Another place to check is your blower. make sure the vanes are not clogged with dust & crud. This system worked at one time otherwise someone would have done something long before you moved in.

Good luck

A lot of good advice in this thread.

Take the temp split of the outdoor condenser coil air discharge Vs surrounding air.

What SEER Rating is the unit?
Eighteen years old, probably a Ten 10-SEER.
The condenser split should be over 20-F depending on the % Relative Humidity & Airflow CFM.

Get a low cost Indoor Thermometer with a humidity Meter at a True Value or Ace Hardware store.

Find out if it has a TXV Expansion Device or a piston fixed orifice metering device.

Probably a fixed orifice, however, it is important to know which it is & if properly sized for the condenser tonnage.

Make certain the Return Air is NOT drawing Hot Air from the Attic! That should show up on the outdoor condenser's air temp split. udarrell _ 2007

Here is a link that might be useful: udarrell.com

Thanks for all the input. The condenser is ~5 years old and the evap coil was replaced at some point. The air coming from the registers was 62*, with the air in the return line at the coils 81*. I suppose this leads me to the point of the system seems to work, but the house just heats up too much? When we had the home inspection done, it was a comfortable constant 76* and there was a 20* drop at the registers then. It was the same outside temp then as it is now, what could have changed??? Aside from that the thing I noticed was that the return air vents for the 1st floor are all in the floor, and the return on the 2nd floor is in the wall at floor level in the hallway (so no return air from the attic). Could this affect the air circulation? I don't know much about this and I'm just a little frustrated that I can't get a well cooled house. Hopefully when we move some furniture in it will help maintain some lower temps. Thanks again for your time.

you are there painting, how many windows do you hav eopen? how often are you going in and out leaving the doors open?

have you changed the filter lately? people moving out, and you doing work inside will stir up a lot of dust. the filters may just be clogged.

no windows open, low odor paint. The doors are not open except coming in to work then 3hrs later to leave. No one other than us coming in and out. I changed the filter right off the bat b/c it was very clogged.