I have a single wide moble home with an addition, it has 100 amp service. I had a two and a half ton air conditioner and heat pump installed a few years ago. It has never cooled my home and I have had a numer of service people check it and they either add freon or take it out saying there is too much. No one can find out why it doesn't cool.

Could you tell me if I need a 200 amp service to make it cool better as it does have cool air?

The size service will not cause an air conditioner to work better or worse. A service not large for an air conditioner enough would cause electrical problems.

I will copy this question over at the Heating and Air Conditioning forum, perhsp someone can help you with an apparent problem with your central air, or more seems like a problem with your AC tech.

2.5 tons is probably too large for the home, but that's an efficiency issue and not a cooling issue.

I'd bet that there is a single return that is blocked or has a clogged air filter.

If there are multiple returns, their should be an upper and a lower one in most of the rooms. The upper return is open to return hot air to the AC in summer and the lower return is open to return cold air to the furnace in winter.