Cooling the house: a how-to
Step 1: Stop heating the house
Anything that produces heat creates extra heat for the Air Conditioner to deal with.
-Replace any light bulbs you cannot hol in your hand with LED. Those florescent pigtail light bulbs need to go too.
-Close ALL window shades or curtains as much as possible without needing to turn on lights.
-Power-off computer monitors. Off-off. Standby mode still generates heat!
-apply heat reflective film on the windows facing South and West.
-Make sure your attic ventilation actually works. A hot attic creates a hot ceiling or the 2nd floor.
Step 2: Force the hottest air to get cooled (central HVAC)
Heat rises. Cool air fall. My furnace (with AC cooling coils) is in the basement and it has to suck hot air from the ceiling of the 2nd floor to the basement for maximum cooling.
-Close the air vents in the basement. It will get cooled regardless because.. Cool air falls.
-Remove air vent covers on the 2nd floor. Vent covers restrict air flow and cool air created in the basement has to travel the furthest to reach the 2nd floor.
-Partially or fully close air return vents on the first floor and basement. Heat rises and if the blower in the basement sucks cool-ish air from the those floors and very little of the really hot air on the second floor gets sucked down.
-Make sure air return vents on the second floor air near the ceiling. Hot air rises so it's at the ceiling. For those worrying about what happens during winter, you are fine. All new homes with a second floor have their air returns near or at the ceiling on the second floor.
-For bungalows (homes with no second floor), consider moving air return vents from the floor to the ceiling on south facing rooms or any room that is always hotter than the rest.