Need to know who can evaluate my hvac/ins

[Newhousenightmare]

I am about to close on my home in a couple of days and I am concerned about the HVAC. Here are some of the specs.. total sq ft 2700. The home has spray foam insulation, low- e vinyl windows. I upgraded the hvac to Amana's 18 seer two stage heat pump with the variable speed airhandler. Problem is that the unit ran constantly all day until 9PM. Temp outside was at 105 at the hottest part of the day and when I left at 8 PM it was 99 outside and 78 inside with the t-stat set at 73 all day long. The unit never cycled off nor did it go into low stage. The installer came out this morning and The gauge he had said 67 on it and he brought it down to 54(adding refrigerant). Today it only got up to 98 and the t-stat was set at 76 so I could see if the charge helped. I arrived at 630PM when it was 97 outside and got a little excited to see that the t-stat had reached the set temp and that it was actually running on low. It only ran on low for about 3 min then went back on high stage. I waited and watched the t-stat until 830 and the unit never cycled off. At this point it was only 90 outside and it was having to run constantly to maintain 76 when it was dark outside.

Can anyone tell me who I might have inspect this that knows a lot about green homes and fresh air intakes. I have no idea what to do here and I am not comfortable with the knowledge of a home inspector on this issue. I want someone that is used to working with this type of equipment to inspect my insulation and overall situation.

Thanks

[heatseeker]

What size is the * The higher efficiency units are designed to run longer to minimize start up amperage. It does sound like your unit is undersized being as though you live in texas and it's a 2700 sq. ft. house. And you are bringing in outside air to boot.

[westcanadian01]

The size of the HVAC especially the heating should also be determine by the size of your house, this is to ensure that once you installed your HVAC there is a proper air ventilation in the room. Higher efficiency HVACs may cost higher compared to the average yet the longevity of the use better.