Did you know it takes 4 to 8 times more electrical current to start your central AC unit than is required to run it? The excess heat generated during startup is damaging to your central air conditioning system compressor. A hard start kit is a start capacitor and a potential relay or PTC ( positive temperature coefficient ) device. They are designed to give your air conditioning compressor an electrical boost upon startup.
Like their name suggests, hard start kits help solve a problem called hard starting, which is when an AC struggles to turn on and then shuts off abruptly after a short while.
If you hear a stutter or clicking noise when you turn on your AC, and your AC doesn’t stay on for long, then those are signs your air conditioner is hard starting. A hard start kit can benefit you if:
- You want to extend the life of the HVAC system
- Your air conditioning system is aging
- You have a home generator
- Low voltage or inconsistent voltage
- Lights dim when AC unit starts
- Compressor won’t start/Humming
- AC system has a TXV metering device
- Multiple AC systems running at once
- Air conditioner trips breaker on startup
- Long refrigerant line sets ( multi-story buildings etc.)
In this article, we’ll answer these 2 questions:
- What exactly does a hard start kit do?
- Do I need a hard start kit or something else?
What does a hard start kit do?
Here’s the basis: A hard start kit makes your AC start smoothly and quickly, which reduces damage to AC parts and prolongs the life of your cooling system.
But why does an AC have a hard time starting up in the first place?
Well, when you turn on your AC, its compressor (the “heart”) powers on to help the system cool your home. However, starting up the compressor requires 4–8 times more electric current than running it.
That’s a lot of electrical strength!
Over time, this jolt of power, which creates a surge of heat, can damage the compressor and other important AC components—especially if your compressor is already old and worn out. And if your compressor is already worn out, it requires even more electricity to get it to shift from “start” to “run” mode.
That’s when a hard start kit saves the day:
A hard start kit helps your AC compressor start up to 10 times faster and more efficiently. It helps overcome the mechanical inertia upon startup. The first couple of seconds for any electrical motor/compressor is when the most strain electrically is placed upon it. Amperage spikes momentarily on startup then drops to normal operating levels. It is this amperage spike that tends to create problems. The excess amperage equals excess heat that can be damaging to your electrical system in your air conditioning system.
Do I need a hard start kit?
Anyone who owns an air conditioner should get a hard start kit because using them will allow the compressor to start up in as little time as possible in the inrush amperage mode. There are actually two scenarios to consider installing a hard start kit:
Scenario #1: Your AC is already hard starting
If your air conditioner is already hard starting, you should contact a professional ASAP to investigate the problem.
“How do I know if my AC is hard starting?”
You’ll know if you notice these 4 signs:
- AC starts, then quickly shuts off after you turn it on: This is called short-cycling, and it means there’s something wrong with your compressor.
- You hear clicking noises when the compressor starts: A clicking sound points to a problem with your compressor, which is using too much power to turn on (hard starting).
- Your compressor trips your circuit breaker: This means your air conditioner is using too much energy to start, so your circuit breaker trips before any serious electrical damage occurs. This is a symptom of hard starting.
- Your lights flicker when you turn your AC on: This is normal to a certain extent, but if you notice a dramatic flicker then it means your AC is drawing too much power to start, which is a symptom of hard starting.
Solution: Contact a professional to investigate the problem. If your compressor motor is struggling to turn on, then a hard start kit could potentially solve the issue.
However, if your compressor is near the end of its life, then a hard start kit may prolong its life for a short time, but shouldn’t be viewed as a long term fix. If your compressor is about to die, talk with your technician about replacing your AC system (it’s usually more cost-effective to replace your whole system rather than buy an expensive compressor).
Scenario #2: You have a new air conditioner
In the past, most single-phase ACs came from the manufacturer with built-in hard start devices, but many newer AC models don’t include a hard-start kit.
If your air conditioner doesn’t have a built in hard start kit (your technician will let you know), you should consider having an AC professional install one. If your compressor is new and in good shape, a hard start kit could extend its life and help it start even in difficult conditions like low voltage or high head pressure.
Need a hard start kit for your AC or heat pump?
Contact Leonard Splaine to schedule an AC repair. We’ll send one of our trusted technicians to visit your home and install a hard start kit for your air conditioner.
You can also give us a call on 703-494-2855