I have an 1800sf home in Colorado with a 2TON A/C. It was installed last year and already had a tune-up at the beginning of the summer season.

The system works great when OD temps are below 95. Above that the system will maintain a set temp but will not follow the setback schedule I have programmed on the thermostat (VisionPro Model.)

#1.) I am considering having an energy audit done and I am looking for a qualified person south of the Denver Metro. Does anyone know of someone? I see that Xcel energy does them, but I am not sure if they are as thorough as one I could have done by a contractor.

#2.) I am interested in doing some home improvements that would reduce the load on the A/C so I can utilize a setback of about 4 degrees during the day. (I want to be at 74 when unoccupied and 70 when occupied.) Generally outside humidity is 15% and indoor is around 35-38%, so I am not concerned about RH, just dropping that temp.
I have some issues I am sure contribute to the Load, but want to know where to start, you know...the biggest bang for my buck. I have multiple plastic dome skylights I am getting a quote on having replaced, I also have single pane windows with storm windows that I am considering replacing. The insulation in the attic covers up to the top of the joists, but I do not know the exact R Value.

If I cannot do both at once, would it be better to replace the plastic dome skylights or my windows? Is this something the energy audit will tell me?

Thanks for any advice, you all were very helpful with the install and related questions.