I live in South Florida, have a single level wood home with very good insulation (R30 in attic - not sure about walls). I have a 3 year old
4 ton Trane XL14i with variable speed air handler. The company that installed it showed me the detailed load calculations and it was not just based on square footage. The even accounted for my 9 foot ceilings, and large bay windows so I am pretty sure I have the correct sized unit. All seems fine, but the unit is running about 10 hrs a day now (wife and kids are home during the day). Here are the details at about 2:00pm yesterday.Outside temp = 95 Condenser exit air = 105 Temp at registers inside = 62-64 depending on which one.
I have the thermostat set at 78 and the house pretty much stays at 78 from 12:00 noon - 5:00pm and never gets down to 77 where it would shut off.
register and outside temp is OK.
I changed some dip switches on the air handler so that the max airflow went from 1600 CFM to 1800 CFM and I re-measured the register temps and they were the same 62-64. I then lowered the max CFM to 1400 and the temps went down to 60-62. My question is what is better? Or is it a wash? The factory setting is 1600.