Soft Start Kits for ACs and Generators – What Houston Homeowners Should Know

Advertisements for soft start kits for home generators and for ACs are everywhere it seems. We are getting many calls from Houston homeowners who are interested in figuring out all the possibilities for affording their own generator for the next storm that comes barrelling through the Houston area. Why, you ask?

Power Outages Drive Demand for Generators, AC

This summer, Hurricane Beryl seemed to take Houston by surprise. It brought more flooding and another disruptive round of weeks-long power outages for many across the city. To make matters worse, CenterPoint the local electrical utility provider has been under fire for the delays in restoring power. Even though Hurricane Beryl was only a category 1 Hurricane, millions were left without power for days and weeks after in hot and humid conditions.

Living in developing world conditions in the nation’s fourth most populous city is a failure on so many levels. And while this article isn’t going to delve into those reasons, suffice it to say that it created a perfect storm of homeowners in the Greater Houston area and Fort Bend County furiously researching generators.

If you can charge a phone, keep your refrigerator/freezer online, and a working AC, life is much easier. A generator can fill the gap when storms knock infrastructure offline. Ads for generators and accessories like soft start and hard start kits began to fill our digital spaces. That’s when the phone calls began to roll in.

Sometimes these electrical accessories can be a godsend and make it possible to run more appliances from a generator, sometimes they aren’t compatible with the AC you have, you have the functionality built-in your AC and you didn’t know it, or worst case, they have no benefit at all. Here’s what to know about soft start and hard start kits and how they relate to your AC and a home generator.

Hard Start Kits and Your AC

What is a hard start kit?

A hard start kit is a large capacitor tied to a relay or timer. Capacitors add electricity to get the compressor in your AC to rotate faster and bring it up to speed. When your AC compressor gets to the right speed, it drops out. Capacitors are a type of failsafe and protect the compressor, the largest motor in your HVAC unit.

For many years, hard start kits were considered a nice-to-have accessory because it could help keep a compressor working for longer. They can also be used to buy extra time for a compressor that may be showing signs of wearing out. In some instances, hard start kits can be used to prolong the life of an AC unit that is older.

Why do we use a hard start kit?

No matter if you use a two-wire or the three-wire setup we prefer, hard start kits decrease the initial inrush of electricity to the compressor when the motor starts. It saves electricity by lowering the overall inrush and reduces wear and tear on the compressor.

For example, if you have a 5-ton AC unit, it may take 21-22 amps to start the compressor. When you have a hard start kit installed, it may only peak at 16-17 amps to start.

Another reason that reducing the amount of electricity to start your AC is important is that it can make it much easier to run a residential AC unit on a generator.

What types of AC units use hard start kits?

Hard start kits can be found on older traditional AC units that have one speed. They turn on, they turn off. Some manufacturers use proprietary hard start kits (start-assist devices) that functioned in a similar way for certain two-speed AC systems.

Variable-speed (three speeds or more) AC units use computer controls to slowly start up and slow down all the AC motors, which means that hard start kits are incompatible. Mini split systems, like those offered by Mitsubishi, are also inverter driven. This can make them easy to connect to a home generator.

If you’re not sure what you have, ask your favorite AC technician who can tell you.

How Do Soft Start Kits Differ?

Soft start kits have a similar name and also can ramp down the initial electrical inflow, but they are a different type of electrical device. They are very popular with RV (recreational vehicle) communities because they can make it possible to run more appliances off a small inverter or generator. AC units in a typical home, on the other hand, draw much more electricity than an RV setup.

Soft start kits function as a sequencer to lower the electrical surge on startup. When used with your AC, if you’re standing outside and looking at the compressor, you’ll hear the buzz of the compressor as it turns on. Then a few seconds later, the fan will start. By turning parts of the AC unit on one at a time, you can decrease the inrush or surge of electricity and reduce the electrical load.

Brands of Soft Start Kits Used for ACs, RVs, and Marine Uses

Keep in mind Soft Start manufacturers give AC contractors access to upgraded or more durable product lines than are available to the general public and/or over the internet. This also makes it possible for a local West Houston area AC company like ours to warranty the part over the counter if it ever fails. This means we can often have a replacement part on the same day.

Because licensed HVAC professionals have training in sourcing and installing these parts, manufacturers can confidently add a better warranty knowing that a soft start kit will likely be installed and used properly in a residential AC. That may not the case if you DIY a soft start kit on your own.

These are some of the most common Soft Starters for ACs:

ICM Controls (ICM870-32A) – While this brand lacks the fancy name, we recommend it because it has an LED indicator and a surge protector built-in. Their ICM870A-16 is for smaller AC units that are 1-3 tons.
Microaire (Easy Start™ Soft Starter) – This brand is the most heavily marketed on social media we’ve observed. They have consumer-facing product lines and ones for HVAC contractors.
Network RV (Softstart RV™) – This brand specializes in soft start AC controllers for RVs.
Carlo Gavazzi Automation Components (Smooth Starter) – This brand originated in Milan, Italy and manufactures sensors, switches, and controls, including soft start kits.
Dometic (Smart Start) – This brand also provides soft starters for rooftop ACs found on RVs.

What is helpful to know is that most residential AC units use between 208-230VAC whereas RV and Marine air conditioners utilize 115VAC (half the incoming voltage).

Do You Need a Soft Start Kit When You Purchase a Generator or Inverter?

We’ve heard claims that go something to the tune of: You need a soft start kit when you buy a generator if you want to run your residential AC.

In our experience, that statement is not always true. There’s nothing worse than someone being told they need a soft start kit but it doesn’t work, isn’t compatible, or doesn’t reduce the energy load at all.

If you are in the market for a generator or inverter, these are questions we recommend asking BEFORE you get a soft start kit:

How much electricity does your home draw normally and which appliances are non-negotiables? This is especially important if you’re not trying to buy a generator or inverter to run your entire home. One way you can tell is to look at your smart electrical meter outdoors from CenterPoint. These smart meters display the highest use of electricity in kilowatts (kw) you have ever used at your home. ProTip: Homeowners with pools or jacuzzi spas may want to consider their pool equipment as a non-negotiable.
How much electricity does your AC need to start up? Because an AC is one of the most electrically-demanding home appliances, you need to know how much electricity it needs to start up. If you’ve ever noticed the lights in your home dimming momentarily when the AC clicks on, you’ve witnessed the AC drawing excess electricity to get itself started. It draws less once it is in motion. Newer, more efficient AC units and especially mini-splits practically sip energy, so you won’t see lights flicker when they turn on. ProTip: If your lights dim noticeably every time the air conditioner comes on, it can sometimes be an indicator that the transformer, which steps down the high-voltage power from the power lines, is getting weak.
What type of fan motor do you have in your AC? ACs with computer-controlled fan motors (ECM or X13) already sequence themselves, so soft start kits do not affect them. These motors have soft start kit functionality built in and are much more efficient to comply with Fan Energy Rating standards.
How will the soft start kit help? Ask your generator installer or electrician to explain why you need a soft start kit and how it will help. They should be able to quantify the benefit for you before you invest in this piece of equipment paired up with your AC.
Will you be upgrading your AC in the next 12-24 months? Depending on which type of AC unit you choose, you may be able to utilize a smaller generator which can affect the size of generator you need.
What are the pros and cons of a larger versus smaller capacity generator or inverter? Sometimes a smaller system with a soft start kit can work very well and save you money. On the other hand, having a larger system with fewer parts means fewer moving parts that can fail.

Electricity Restoration After Hurricane Beryl

From an AC contractor’s perspective, I’ve seen more electrical part failures on ACs we service after Hurricane Beryl than before the storm arrived. Power restoration from CenterPoint has been rough on the electrical system as a whole and the blips and surges have caused common electrical parts to fail more than usual as a direct result.

In the meantime, we have had customers call us requesting soft start kits for their AC without really understanding what they are or how they work. We want customers to understand more about how they are used so they can ask the right questions if they are thinking about sourcing a generator. We have also put together safety tips when using a generator with your AC.

What you don’t want is an electrician or generator provider to install a soft start kit on your AC and then void your manufacturer’s warranty without careful consideration. Include a licensed HVAC technician as part of the conversation. Then, weigh the pros and cons before you decide. If you need a local recommendation, we recommend Thuan Ho of Critical Power Solutions located in Sugar Land and (281) 771-8850.

Questions About How Your AC Works With a Generator? Call Us

If you have questions about how your generator can work with your AC and whether you need a soft start system or if you have one already built in, give your favorite AC contractor a call to get some help before you invest.

My family installed a whole home generator after Winter Storm Uri and we put it to the test after Hurricane Beryl. This enabled us to help customers on Houston’s West side including Richmond, Katy, Fulshear, more quickly after the storm. Contact me, Rob Terry, owner of Terry’s A/C & Heating, at 281-495-7830 if our team can help you replace an older AC unit for one that is more efficient and works better with your generator. We can also install a soft start kit if you need one and help you navigate questions to ask when sourcing a generator/inverter to run your AC and other essential appliances for the next storm.

Photo credit: Canva.com/JodiJacobson