It is 100 degrees outside, my 4 ton packaged heat pump unit is set at 75 degrees it will not cool the house to that temp, the filter changed, brand new unit, it is 85 degrees in the house. I can feel the air coming out through the vents just not as strong. Is there some tips I can use to help my unit cool more efficiently? It does get cool after the sun goes down

What part the world do you live in? Sure it gets cooler as the sun goes down!

My best guess is your unit cannot keep up the demand you are putting on it, so and my best guess is, another unit with more BUTs.

In most areas on the north american continent, including Canada, where my sled dogs are hot too, we just dig ourselves in and hope for the best possible cooling temp because it will cost me an arm and a leg to cool my 1100 sq ft home, with a lot of trees around.

Get an assessment of your needs right now for your air condition needs. I have, maybe one hour when I come home at five and am uncomfortable, then I turn it off and open the windows.

If your unit can't pull below 85 you have a real problem. I live in 115 degree days and 90 degree nights. If new find out what the deal is.

Insulation can get pulled into the squirrl cage blower wheel. Return flex ducts can collapse - all restricting airflow.

Find out what is going on - that is definitely unaccepatable unless you live in a glass house that is 3000 sq ft (undersized unit)

Check for a duct leak as well you can do the old door trick (http://phxheatpump.blogspot.com/2012/02/how-do-i-know-i-have-duct-leak-old-door.html)but probably you would have it in the supply side