Came out to perform preventative maintenance on New Carrier system. I did a full inspection of equipment. I inspected the equipment in attic first. System is a 90% high efficiency furnace with a 5 ton AC system. I checked all zones of zoning system, wiring, electrical components, drains, and overall condition. I checked thermostat operations, wiring, amps, capacitor, contactor, compressor, and fan motor. Checked temperatures and pressures of condenser. System is operating properly. Customer explained that in the heat of the day the system won’t always reach desired temperature in home. She explained that it stays fairly comfortable, just not were they would like it. I explained that the builder put a 5 ton system on a 2,900 sqft home, and added spray foam to reduce heat load. By the calculations I did, the system is close to a ton short of air. Which means the 5 ton AC has to work overtime to keep the home at desired temp, and has difficulty doing it when it’s 100 degrees outside.