My daughter just moved into her first apartment. It has a Lennox E10 unit for heating & AC. The thermostat is a Lux DMH110b non-programmable. It is June in Iowa. Last evening she got back and the temp in the apartment was 74. She turned system on and set to cool to 70. It ran for 7 hours and the temp went UP to 75!

The landlord has had their HVAC contractor look at it 3 times- he says it's fully charged and everything looks good and he can't fix what ain't broke!

Well, I respectfully argue something is wrong. I'm visiting this weekend. What do I look for?

Thermostat may not be the issue or the unit either. How much solar load? Top floor? Ceiling insulation? Trees? What is temp of outlet register air? 74-76 is possibly where it will run when ambient temp is 90+.

If it is not cooling it is broken. How much air is coming out of vents? Could have a dirty indoor coil or the filter could be dirty. What does the outdoor coil look like? Is it clean?