Written Written This is a very difficult question to answer, and if you bump across an hvac engineer or technician that "knows" the answer, you should be sure he is lying.The air conditioner's monthly (or yearly) total consumption depends on many "irrelevant to the air conditioner" factors like:The weather of every year (mean season temperatures) .  The air conditioner will cost more on "hot years".The user's prefferences (how cool you want your home to be)The total hours of air conditioning times (depends on the resident's life - the cost will be different for a family that both husband and wife work in the morning with kids going to school from a family that the wife doesn't work and the air conditioner runs during morning hours)As a rough estimation, you could use the following formula:air conditioning yearly cost = "air conditioning months" x "air conditioner's total electrical power"  x "4 hours a day of air conditioner running at total power" x "$/kWh electrical cost"but as i mentioned above, this calculation is a very rough estimation and it depends on many factors.