What is an AC Hard Start Kit? A Homeowners Guide

What is an AC Hard Start Kit

Perhaps your AC struggles with turning on and then quickly shuts off after just a short while.

Your Air conditioning is suffering from hard starting. This can result in serious electrical damage if left unresolved. If your AC unit is hard starting, you should contact a professional ASAP.

Installing a hard start kit can help.

In this guide, discover these kits, including how they work to help your AC start smoothly and keep your cooling system in good shape.

⭐ What is a Hard Start Kit?

AC hard start kit

The hard start kit is designed to help your air conditioner when it’s having a hard time starting.

A hard start kit has an energy-storing capacitor, giving extra juice to your AC compressor, which is responsible for turning on and operating the whole system.

The compressor is the heart of your air conditioner — it’s the hardest working component out of all the AC parts.

Extending the life of your compressor and preventing compressor motor damage by feeding it the same amount of energy each time it turns on is the main function of a hard start capacitor.

⭐ How Does a Hard Start Kit Work?

ac compressor cycle

To understand a hard start kit’s role in your AC system, you must first understand the air conditioning compressor.

An AC compressor uses more energy to start up than it does while operating continuously.

It can take at least four times more electric current to start a compressor than to run it.

Over time, this extra push of power and the excess heat it causes can strain and damage your compressor and various other important AC components.

The older your compressor is, the more energy it will take to start your air conditioner.

A hard start capacitor shortens the compressor’s time to kick in, thereby shortening the AC startup time and reducing the amount of electricity used in the process.

A kit can solve any problems with how your AC starts, lengthening your compressor’s life and letting your HVAC system cool the house down without risking damage.

⭐ Is a Hard Start Kit Necessary for Your Compressor Motor Problem?

outdoor ac condensing unit showing internal components

If you’ve noticed anything unusual about how your AC or heat pump operates, such as strange noises when your compressor starts, it might be time to have an HVAC technician install a hard start kit.

Let’s take a look at two possible scenarios involving your HVAC system and discuss how installing a hard start kit with a potential relay can make a huge difference in the startup period of your unit.

⚒️ Problem: If Your Old Air Conditioner is Hard Starting.

choosing the right ac

Older air conditioners are less likely to have hard start kits, making them more susceptible to problems associated with hard starting.

Here are some signs that your air conditioner is hard starting:

1. The AC starts, then shuts off again quickly.

This common process is called short cycling. It indicates there’s a problem with your compressor.

2. A clicking noise points to the compressor starting.

A healthy compressor should be relatively silent as it turns on.

That clicking sound indicates something wrong with the compressor.

If you hear clicking noises when your air conditioning system turns on, that’s an indication that the compressor is using too much power.

3. The circuit breaker trips.

This indicates that your compressor needs too much energy to turn on.

Your circuit breaker trips as a safety measure before electrical damage occurs.

4. The lights flicker as the compressor turns on.

Flickering lights are a relatively common side effect of HVAC systems starting up since the process takes so much power.

However, a dramatic flicker could be a sign that your AC is drawing too much power for the metering device to handle.

⚒️ Solution

If your older AC unit is exhibiting any of these signs, contact your local HVAC experts immediately.

It could be that installing a kit will solve the problem.

That said, if your compressor is nearing the end of operations, your AC repair technician might recommend replacing the unit instead.

It’s often more cost-effective than purchasing an expensive compressor to replace an air conditioning system.

⚒️ Problem: If You Have a New Air Conditioner.

Ductless mini split multizone AC Installation

Many newer AC models come with a hard start capacitor built in as one of their main components.

However, most single-phase ACs generally have lower-quality run capacitors and could benefit from having a higher-quality kit with a potential relay installed.

Even with a new compressor that’s in top shape, a hard start kit could significantly extend its useful life by helping it start-up under strenuous conditions, such as low voltage or high head pressure.

⚒️ Solution

Not sure whether your new AC has a hard start kit built in?

Contact an HVAC professional to evaluate your system.

They can recommend any necessary upgrades.

⭐ Frequently Asked Questions

Still have questions about what a hard start kit can do for your AC system?

Check out these frequently asked questions from other homeowners.

Can I Install a Hard Start Kit Myself?

It is recommended to hire an expert for installation.

Professional HVAC technicians will be able to diagnose the exact problem with your AC and will also be able to choose the right size and type of kit for your unit.

Plus, if the best solution to your AC trouble is to replace the entire system, your technician will be able to alert you before you spend money on expensive components.

How Long Will a Hard Start Kit Last?

The longevity of your hard start kit depends on the type of kit you install.

For instance, a PTC hard start kit (positive temperature coefficient) is among the cheaper options but not necessarily appropriate for long-term use and usually stops functioning after about a year.

On the other hand, a hard start kit with a mechanical potential relay will be more expensive but can last as long as a decade.

Does a Hard Start Kit Save Energy for Your Air Conditioning System?

Again, this depends on the type of kit installed.

A higher-end hard start kit saves money by closely monitoring your system and telling it when to shut off for maximum efficiency.

Considering ACs account for 12% of all energy usage in the United States, having a high-quality hard start kit installed could go a long way toward decreasing your energy use and lowering your electricity bill.

⭐ Using a Kit for Your AC or Heat Pump


So is a hard start kit worth it? Yes

— whether you’re the proud owner of a new AC system or a long-term homeowner looking to extend the life of your unit for one more summer, you can benefit.

Learning about hard start kits can save you money on your electric bill and reduce the risk of dangers associated with a hard start.

Get in touch with your local HVAC experts today to learn more about hard start capacitors, air conditioner maintenance, and troubleshooting.

Dealing with other common AC problems? Check out: Top 18 Common AC Problems and Solutions.

And if you live in the North or Central Okanagan region, check out Phyxter Home Services for all of your air conditioning needs. Your choice for friendly and affordable HVAC services.

Related Reading: What is the Best AC Temperature in Summer

Jake Gibson

Jake Gibson is a force to be reckoned with in the HVAC industry. As the CEO of Phyxter, he has made it his mission to revolutionize how contractors work. With a background in HVAC, entrepreneurship, and technology, Jake brings innovation and expertise to this traditional industry.

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