Understanding the Difference Between Contractor-Grade and Consumer-Grade Tools

By MYGORP Supply – South Louisiana’s Family-Owned Distributor for Tools, HVAC, and Appliance Parts

When an HVAC system stops cooling properly, one of the first components technicians check is the capacitor. Small but essential, capacitors provide the initial jolt of electricity that gets motors, compressors, and fans running — and keep them operating efficiently.

Selecting the right capacitor is crucial for system performance, safety, and reliability. Here’s what every technician should know when choosing the correct replacement.

1. Understand the Two Main Types of Capacitors

There are two common types used in HVAC systems:

  • Start Capacitors: Provide a high burst of energy to start a motor. They are only active during startup and then disengage.
  • Run Capacitors: Remain in the circuit to maintain a consistent voltage supply while the motor is running.

Using the wrong type — or mixing them up — can result in poor performance, overheating, or complete motor failure.

2. Match the Microfarad (µF) Rating Exactly

The microfarad rating (µF) measures a capacitor’s storage capacity. It must match the original part’s rating within the manufacturer’s specified tolerance (typically ±5% or ±6%).

If the µF rating is too high, the motor can overheat; too low, and it may not start or run efficiently. Always check the rating printed on the old capacitor or the equipment’s wiring diagram before ordering a replacement.

3. Verify the Voltage Rating

HVAC capacitors are commonly rated for 370V or 440V.

  • If the original was 370V, it’s acceptable to upgrade to 440V for improved durability.
  • Never downgrade from a higher to a lower voltage — doing so risks short circuits or premature failure.

Remember: the voltage rating indicates the maximum the capacitor can handle, not the system’s operating voltage.

4. Choose a Trusted Brand and Distributor

Cheap, off-brand capacitors often fail early or deliver inconsistent performance. Look for UL-listed or OEM-quality components from reputable manufacturers such as SUPCO, DiversiTech, or Mars.

Buying from a verified distributor (like MYGORP Supply) ensures authenticity and quality control. Counterfeit capacitors are a real issue in the HVAC trade — they may look identical but won’t meet performance or safety standards.

5. Consider Environmental and Usage Factors

Heat, humidity, and vibration shorten capacitor life.

In South Louisiana and similar climates, where HVAC units face high humidity and heat, upgrading to a 440V or heavy-duty capacitor can extend service life.

For outdoor condensers, choose capacitors with corrosion-resistant housings and sealed terminals to prevent moisture intrusion.

6. Always Discharge and Handle Safely

Capacitors store electrical energy even after power is disconnected. Always:

  • Use an insulated screwdriver or resistor to discharge before handling.
  • Wear insulated gloves and safety glasses.
  • Mount the replacement securely with all connections tightened to manufacturer torque specs.

Safety first — even small capacitors can deliver dangerous shocks if mishandled.

7. Keep a Range of Common Values in Stock

For technicians and small distributors, having an assortment of common µF and voltage combinations saves valuable time during service calls. Stocking popular dual-run capacitors (e.g., 35/5 µF 440V, 45/5 µF 440V, etc.) ensures you’re always ready for quick replacements without extra trips or order delays.

The MYGORP Supply Advantage

At MYGORP Supply, we stock genuine capacitors from trusted brands — perfect for HVAC professionals who value reliability and fast service. Whether you’re replacing a single unit or replenishing your field inventory, our team can help you identify compatible components and get them shipped quickly.