Your air conditioner's main job is to remove heat from the home.  Many homes have installed window screens to reduce the amount of searing heat brought into the home from the Arizona sun. While this greatly reduces the "solar gain", the home tends to be dark as a result of the screens, as such, lights are turned on throughout the home. 

Lights produce heat, and a lot of it.  If you can tolerate the pain, try touching your standard, or CFL (compact florescent light) 5 minutes after you turn them on. They are very effective heaters. Your air conditioner must remove that heat as well.  Don't heat your home while you are cooling it.

LED's provide excellent light, use little energy, produce very little heat, and last longer than traditional or CFL bulbs. LED's are the best option available.  

Your air conditioner and heater need unimpeded airflow to do their job properly.  When it comes to HVAC (Heating, Venting, Air Conditioning), airflow is king!

Air conditioners need 400 cubic feet of air per minute for each ton of air conditioning.  Lower airflow will reduce capacity, damage equipment, and cause it to struggle on the hottest days.  Also, low airflow will cause your system to use much more electricity to do the same job. 

Your furnace operates under the same principle. As your furnace produces heat, airflow moves the heat into the home, rather then escaping up the flue.  This wastes energy and robs you of comfort.

NCI studies show that over 80% of home heating and cooling systems do not meet minimum airflow standards.  Causes include; leaky duct, improperly sized equipment, and poorly designed duct systems. 

3 Simple solutions to improve airflow:

1. Change your air-filter regulary
2. Clean vents and registers to ensure that air flows properly
3. Open your registers - When we close registers in un-used areas of the home, we diminish total airflow.  Thus reducing efficiency and capacity of the system.