Well, it does work downstairs but not upstairs. the system runs 24/7 and the temperature hovers around the low 80s when the outside temperature is in the 90s. The filters are clean and the system has been pressure washed to remove any dirt.
The house, located in s.e. pa, has a geothermal system with the airhandlers for the 2nd floor in the attic. the units themselves are in an insulated "room" in the attic. on a recent inspection, the hvac contractor found that the coil on the airhandler had "iced up". one thing that the hvac guys did is to SLOW DOWN the fan speed so that the air flowed across the coil more slowly (i think i have this right). The duct work in the attic is insulated with foam insulation.
the HVAC contractor, a good guy, is trying to figure out a fix for this. the steps he recommends:
1. change the attic insulation to R-38 from R-30. The sizing of the system was made assuming R-38 but the wrong insulation was put in the attic by the builder.
2. add an attic fan to move some of the very hot (130 degrees+ on days when the o/s temp is in the 90s) out of the attic. the roof has roof vents but the upper ones are not at the very peak of the roof, they are down the roof by about 20% of the roof (in other words, off about 20% from the top of the roof).
a. do insulation changes often make a dramatic change in the efficiency of the system?
b. i am reluctant to put another hole in my roof or add another mechanical system that could fail in terms of an attic fan of some sort. is such a device likely to reduce the high temperature that much and should i truly be concerned about having another mechanical device?
c. i am not on any sort of witch hunt but i do want this system to work well. if i wanted to seek a thoughtful, unbiased opinion and evaluation of the system, where would i go? an energy consultant? another hvac person? i worry that my hvac people (like i said, i like them and they are good people and i believe competent) may not be able to step back and evaluate the system with a critical eye.
thank you all for your input.