Start Run capacitors are necessary for HVAC air conditioner and heat pump systems.
Since electric motors can have a big power draw when they first start, a capacitor can add the extra boost needed to start a motor running.
What is a Start Run Capacitor?
Electric motors have a large power draw when they first start, and after moving, the power draw drops.
HVAC units have two main electric motors, including the condensing fan motor and the compressor.
Both motors usually have the leads go to a big capacitor to give extra power when starting.
A capacitor can also work when a motor is running to stabilize a sporadic power source stopping heavy up and down spikes.
A high cost to replace a Start Run capacitor would be $300-$400.
Keep in mind costs usually go up during the summer when it is hot since HVAC techs are in such high demand.
If you get the capacitor replaced in the spring when the temperature is in the 70s, the cost will likely be on the lower end.
If you get the capacitor replaced in the middle of summer and the temperature is in the 90s, it will likely be at the higher end.
Supply and demand can cause the cost to go up and down. HVAC techs often have very little work when the weather is nice but become hugely in demand when the temperature gets hot.
Every HVAC company will also price things differently, with some having a service call diagnostic charge for coming out and troubleshooting the problem.
How Much Does It Cost to Buy a Start Run Capacitor?
They can be bought at an HVAC supply store or online on Amazon or eBay.
The new capacitor must match the old one in Amps (uf Micro Farads) and Volts as not to cause damage to the HVAC unit.
How Hard is a Start Run Capacitor Replace?
Replacing a Start Run Capacitor is an easy relativity task, but care has to be taken since high voltage is involved.
The power must be shut off to the unit, and care needs to be taken with the capacitor since one can hold a charge even with the power off.
The capacitor is usually held in place with a screw and has three leads on the top labeled HERM, FAN, and Common.
HERM is for the compressor, FAN is for the condensing fan motor, and common is the shared leg.
A correct replacement capacitor will need to be bought, which must match the Amps (uf Micro Farads) and Voltage of the old one.
If you have worked with high voltage devices before, replacing a Start Run Capacitor is not difficult.
Of course, if in doubt, be sure to call a professional HVAC tech