Air Conditioner Costs
Air Conditioning Operating Cost Guide
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500 kWh used per season x $0.25 = $125.00 - that's your electricity cost to run the air conditioner for a season.

How Much Does It Cost Per Hour to Run An Air Conditioning System

This is an even simpler calculation. Using as an example information from our example air conditioner's data tag,

((5000 BTUh) / (10 SEER)) = 500 Wh

500 Wh x $0.25 = $0.12 per hour to run our air conditioner.

Other Equations Using SEER Ratings

We can also write the SEER equation shown above as:

SEER = BTUs / Watt-hours
where "watt-hours" = (number of hours of system operation) x (watts used per hour)

For more definitions of heating and air conditioning terms see SEER RATINGS & OTHER DEFINITIONS.

Questions & Answers about the Operating Cost & Energy Consumption of Air Conditioners & Heat Pumps

Question: How Can I Reduce the Operating Cost and Energy Consumption of my Air Conditioning & Heat Pump System?

As we discussed at Questions & Answers about the Energy Star Program's SEER and EER definitions and equipment ratings,

Answer: List of Air Conditioning & Heat Pump System Steps or Installation Details that Save on Operating Cost

According to SoCalEdison's "Comprehensive Packaged Air Conditioning Systems", Residential and commercial air conditioning is responsible for the largest share of peak demand in California, contributing approximately 33% of peak demand. [3] [4]

Saving money on central or even portable air conditioners and heat pumps starts by buying equipment with a high SEER (Seasonal Energy Efficiency Ratio (SEER)) rating. But as SoCalEd points out [4], the purchase of high efficiency (high SEER) HVAC equipment captures only a small part of the total savings in air conditioning or heat pump costs that could be saved by other installation and maintenance steps that we outline here [quoted, paraphrased, and expanded from [4]]:

Proper Sizing of the Air Conditioner. Supporting proper sizing in residential and commercial units can yield savings. Contractors frequently install oversized systems to avoid potential comfort and call back risks. See COOLING CAPACITY, RATED, and also, because an oversized air conditioner is likely to fail to adequately dehumidify building air, also see A/C Not Dehumidifying.

[Air Conditioner & Heat Pump] Refrigerant Charge and [compressor/condenser] Airflow. Between half and three-quarters of all packaged air conditioning units suffer from incorrect charge and low airflow. For both new and existing equipment, ensuring the proper refrigerant charge and airflow can increase efficiency. [5] See REFRIGERANTS and see REFRIGERANT LEAK DETECTION where we describe types of A/C refrigeration system leaks, where they occur, and how they damage the system. Also see REFRIGERANT LEAK REPAIR. [We {DF] speculate that this problem may be more severe for residential air conditioners and heat pumps than for those commercial units whose design includes a refrigerant receiver.]

[HVAC Air] Duct Sealing. Ensuring tight ducts in residential and commercial installations yields 10- 18% energy savings.6 The peak load reduction can be higher, yielding a demand savings of 25%.[4 and citations therein]

See our articles on air duct leaks:
  LEAKY DUCT CONNECTIONS
    Leaky or Missing Air Ducts
    Hidden Missing Air Conditioner Duct
    Duct Retrofit Leaks
    Rooftop Duct Leaks
    RETURN DUCT AIR LEAKS
    SUPPLY DUCT AIR LEAKS

In our [DF] OPINION in addition to sealing duct leaks, better attention to balancing the quantity of return air available to the air handler with the supply duct and register system is needed at many buildings. See INCREASING RETURN AIR

In our [DF] OPINION, the most basic homeowner maintenance task that can reduce air conditioning and heat pump operating tasks is to be sure that air filters are in place, properly selected, sized, installed, not leaky, and that the filters are changed on a regular schedule. See Dirty Air Filter Problems and see AIR FILTERS for HVAC SYSTEMS for details. Also see our suggestions at AIR FILTERING STRATEGIES.

HVAC Economizers. Research shows that the majority of [HVAC] economizers do not function as intended. Use of the Whole Building Diagnostician tool in new and existing buildings in California has confirmed that problems with outside air economizers are endemic. The potential savings from fixing a malfunctioning economizer are approximately 10 – 15% of total packaged air conditioning load. In addition, enabling damper function is a prerequisite for further savings from demand controlled ventilation. [4 and accompanying citation]

Definition of Economizer for HVAC systems: economizers are devices designed to reduce the operating cost (and energy used) in mechanical systems, principally by re-using heat (or cooling) already produced within the system. Examples of economizer designs in HVAC systems include details that may be found both at the ductwork / air handling system (this is the common use of "economizers on HVAC systems) and also right inside of the compressor/condenser unit (a technical use of HVAC economizer heat exchange theory):

• Air-to-air heat exchangers that heat incoming fresh air (makeup air) being introduced into the duct system during the heating season by using the heat from combustion exhaust or other sources.
• Refrigerant tubing co-soldering of the high pressure (high temperature or "high side") refrigerant piping alongside of low pressure (low temperature or "low side") tubing at certain locations in the air conditioning or heat pump system to improve system efficiency. We explain this A/C or heat pump refrigerant line soldering/brazing detail at REFRIGERANT PIPING & DISTANCES - at the subtopic: Technical Note on Refrigerant Piping: HVAC economizer detail

HVAC Controls. Appropriate controls which enable variable heating and cooling conditions based on occupancy are also critical. With a comprehensive program to address all of these opportunities, the savings per packaged air conditioning unit easily approach 20 percent.[4]

Readers should also see ENERGY SAVINGS in buildings for our home page on this topic.

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A/C COMPONENTS
A/C DATA TAGS
A/C - HEAT PUMP CRITICAL DEFECTS
A/C DIAGNOSTIC FAQs
A/C REFRIGERANTS
A/C TYPES, ENERGY SOURCES

AIR CONDITIONER BTU CHART
AIR FILTERS for HVAC SYSTEMS

AIR HANDLER / BLOWER UNITS

ANIMAL ALLERGENS / PET DANDER
ANIMAL ENTRY POINTS in buildings
ANIMAL ODORS IN buildings
APPLIANCE EFFICIENCY RATINGS
ASBESTOS IDENTIFICATION IN buildings

BACKUP HEAT for HEAT PUMPS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books

CAPACITORS for HARD STARTING MOTORS
CAPILLARY TUBES
CLEANING & Legionella BACTERIA
COMPRESSOR & CONDENSING COIL, A/C

CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
COOLING LOAD REDUCTION by ROOF VENTS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS

DATA TAGS on AIR CONDITIONERS
DEFINITION of Heating & Cooling Terms
DEHUMIDIFICATION PROBLEMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
DUCT SYSTEM & DUCT DEFECTS
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST CONTAMINATION FROM HVAC?

EDUCATION, HVAC SCHOOLS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRICAL POWER SWITCH FOR HEAT
EVAPORATIVE COOLING SYSTEMS
EVAPORATOR COIL or COOLING COIL
EXPANSION VALVES, REFRIGERANT

FAN, AIR HANDLER BLOWER UNIT
FAN AUTO ON Thermostat Switch
FAN CONVECTOR HEATERS - HYDRONIC COILS
FAN LIMIT SWITCH
FAN NOISES

FURNACES WARM AIR HEATING SYSTEMS

GAS EXPOSURE EFFECTS, TOXIC
GAS DETECTION & MEASUREMENT
GAUGE, REFRIGERATION PRESSURE TEST

HEAT LOSS (or GAIN) in buildings
HEAT PUMPS
HUMIDITY LEVEL TARGET

INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSPECTION LIMITATIONS, A/C SYSTEMS

LOST COOLING CAPACITY

MANUALS & PARTS GUIDES - HVAC
MOTOR OVERLOAD RESET SWITCH
OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES

NOISE AIR CONDITIONER / HEAT PUMP
NOISE / SOUND DIAGNOSIS & CURE
  Air Leak Noises
  AIR CONDITIONING & HEAT PUMP NOISES

PORTABLE ROOM AIR CONDITIONERS
PRESSURE READINGS, REFRIGERANT

REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS
REPAIR & DIAGNOSTIC FAQs for A/C

REFRIGERANTS
  GAUGE, REFRIGERATION PRESSURE TEST
  REFRIGERANT CHARGING PROCEDURE
  REFRIGERANT DRIERS & FILTERS
  REFRIGERANT LEAK DETECTION
  REFRIGERANT LEAK REPAIR
  REFRIGERANT METERING DEVICES TEVs
  REFRIGERANT METERING CAPILLARY TUBES
  REFRIGERANT PIPING & DISTANCES
  REFRIGERANT PRESSURE READINGS
RETROFIT SIZING for A/C or HEAT PUMPS

SEER RATINGS & OTHER DEFINITIONS
SYSTEM OPERATION
SWAMP COOLERS

THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES

• [1] U.S. Government EnergyStar Program, ENERGY STAR Program Requirements for ASHPs and Central Air Conditioners – FINAL DRAFT, found at http://www.energystar.gov/ia/partners/prod_development/revisions
  /downloads/ac_ashp/Final_Draft_CAC_ASHP_Eligibility_Criteria.pdf
• Air-Conditioning and Refrigeration Institute. Standard 210/240 “2003 Standard for Unitary Air-Conditioning and Air-Source Heat Pump Equipment.”
• [2] SoCalEdison Comments for ASHP/CAC Options Paper, Web search 07/22/2011 - SoCalEdison.pdf, note that by its name this article contains comments by a representative from SoCalEdison in response to a request for input to help EnergyStar develop an HVAC standard for 2006, but neither addressee nor writer are fully identified. SoCalEdison is an acronym for Southern California Edison, an Edison International Company and one of the largest electric utilities in the United States. According to SoCalEdison, "Residential and commercial air conditioning is responsible for the largest share of peak [electrical energy] demand in California,contributing approximately 33% of peak demand." [citation:
  http://asset.sce.com/Regulatory/Energy%20Efficiency%
  20Filings/SCE2507COMPREHENSIVEHVAC.pdf ] - also see the Kema -Xenergy energy use citation just below.
• [3]Kema -Xenergy, “California Statewide Residential Sector Energy Efficiency Potential Study,” April 2003,
  and Kema-Xenergy, “California Commercial Sector Energy Efficiency Potential Study,” July 2002. Base
  information is factored by 0.367 to get SCE portion of savings.
• [4]Comprehensive Packaged Air Conditioning Systems, SoCalEdison, web search 7/23/2011, original source: http://asset.sce.com/Regulatory/Energy%20Efficiency%20Filings
  /SCE2507COMPREHENSIVEHVAC.pdf
• [5] Chris Neme, National Energy Savings Potential from Addressing HVAC Installation Problems, prepared
  for US Environmental Protection Agency, March 1998

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• Complete List of Air Conditioning & Heat Pump Design, Inspection, Repair Books at the InspectAPedia Bookstore.

• Modern Refrigeration and Air Conditioning, A. D. Althouse, C.H. Turnquist, A. Bracciano, Goodheart-Willcox Co., 1982
• Principles of Refrigeration, R. Warren Marsh, C. Thomas Olivo, Delmar Publishers, 1979
• "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
• Refrigeration and Air Conditioning Technology, 5th Ed., William C. Whitman, William M. Johnson, John Tomczyk, Cengage Learning, 2005, ISBN 1401837654, 9781401837655 1324 pages
• Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.).
• Air Conditioning Inspection, Diagnosis, Repair, Efficiency all the basics for home owners, inspectors, new repairmen
• Air Conditioning SEER - New DOE Air Conditioner and Heat Pump Efficiency Standard
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Fiberglass in Indoor Air, HVAC ducts, and Building Insulation