The amount of current an AC unit draws varies significantly depending on its type, size, efficiency, and operating conditions. For central residential air conditioning systems, the amperage typically ranges from 15 to 40 amps.
Typical Amperage for Central AC Units
Central air conditioners generally require higher current due to their substantial cooling capacity designed for an entire home. The specific amperage draw correlates directly with the unit's cooling capacity, which is often measured in "tons."
Here's a breakdown of common amperage draws for residential central AC units:
| AC Unit Size (Tons) | Typical Amperage Range (Amps) |
|---|---|
| 2-ton | 15-20 amps |
| 3.5-ton | 25-30 amps |
| 5-ton | 30-40 amps |
Note: These figures represent the running amperage. Startup amperage (LRA - Locked Rotor Amps) can be significantly higher, sometimes 3 to 5 times the running amps, for a brief moment as the compressor initiates operation. Modern AC units with variable-speed compressors or soft-start kits can reduce this initial surge.
Factors Influencing AC Current Draw
Several factors contribute to how much current an AC unit consumes:
- Tonnage (Cooling Capacity): As shown in the table, larger units (higher tonnage) designed to cool bigger spaces will inherently draw more current to perform their function.
- Efficiency Rating (SEER/EER): More energy-efficient units, indicated by higher Seasonal Energy Efficiency Ratio (SEER) or Energy Efficiency Ratio (EER) ratings, might draw slightly less current for the same cooling output compared to less efficient models.
- System Age and Condition: Older units or those with poorly maintained components (e.g., dirty coils, low refrigerant) may work harder and draw more current to achieve the desired cooling.
- Outdoor Temperature: On hotter days, the AC unit's compressor works harder, potentially leading to higher current draw.
- Voltage: The current draw is inversely proportional to the voltage for a given power output. Residential central AC units typically operate on 240-volt circuits, which helps keep the amperage lower than if they ran on 120-volt circuits for the same power.
Understanding these factors helps in estimating the electrical load an AC unit places on a home's electrical system, which is crucial for proper circuit sizing and safety.
