Buyers Guide & Information

Best AC Surge Protectors Reviewed

We review the most reliable devices that protect from power surges in the home.

Power surges happen. Brownouts, blackouts, loss of power, and tripped breakers. These power issues can cause havoc on your home AC. When power is restored, or when the power to the home flickers, sensitive components of our electrical systems can get over-charged, burn up or short circuit.

The solution is to invest in surge protectors. This article is for anyone looking to protect their home with the best AC surge protectors. We review, compare, and evaluate the best surge protectors on the market to help you find the perfect match for your needs.

Best Type 2 Model


Our Top Pick

Intermatic AG3000_1
Intermatic AG3000

Best Panel System

Leviton 51120-1
Leviton 51120-1

How AC Surge Protectors Work

Everything you plug in has a power draw. There is a minimum current required to supply power to that device. This draw is rated, and the device itself will demand that amount to power on or run. When you plug the device into a surge protector, you are preventing the draw from being overloaded.

A surge protector sends the draw current to the device that is plugged in from the supply (the outlet, for example, that the surge protector is plugged into). If that supply has a surge or power, the surge protector sends the over-draw to a ground and not to the device where it can cause damage.

Why Investing in AC Surge Protection Is a Good Idea

Modern AC systems use a lot of sensitive electronic parts, especially with smart home integration and high-efficiency systems. Even though an air conditioner can cause power fluctuations inside the home (considerable power draws when they come on, etc.), they are also weak against surges coming in from outside your house.

When you invest in AC surge protection, you are helping to minimize the chance of damaging your entire cooling system, causing irreversible failures or costly repairs. Even if the system is under warranty, a lot of claims will be denied and filed under misuse or abnormal use conditions, voiding the companies requirement to repair or replace it.

With surge suppression installed, the warranty won’t be voided, and you will generally get a warranty from the surge protection device as well, adding to your peace of mind.

AC Surge Protectors Compared

ModelSPD TypeProtection TypeMCOVPrice
Intermatic AG3000Type 1, Type 2L-G, L-L, L-NL-N: 150V / L-L: 300VCheck Price
EATON CHSPT2ULTRAType 2L-G, L-L, L-NL-N: 150V / L-G: 150V / L-L: 300VCheck Price
Leviton 51120-1Type 2L-G, L-L, L-NL-N: 150V / L-L: 300VCheck Price
Siemens FS140Type 2L-G, L-L, L-NL-N: 150V / L-G: 150V / L-L: 300VCheck Price
Intermatic Smart Guard IG2240-IMSKType 1L1-N, L2-N, L1-G, L2-G, N-G, L1-L2L-N: 150V / L-G: 150V / L-L: 300VCheck Price
Pipeman’s Installation SolutionType 3L-LL-L: 250VCheck Price
Belkin 12-Outlet Power StripType 3L-G, L-LL-G: 150V / L-L: 300VCheck Price

Choosing a Quality AC Surge Protector Device

You shouldn’t go out and buy any old AC surge suppression or surge protection device. There are a lot of factors you need to consider first. Below, I summarize those factors.

Modes of Protection

There are three main modes of protection. These modes are known by their initials, LG, LN, and NG. LG, or Line to Ground, pulls the overdraw to the grounding wire from the line that feeds the protector. LN, or Line to Neutral, bypasses the ground line and sends it to overflow current through the neutral line of the wiring.

Finally, the NG or Neutral to Ground feeds any surges or spikes from the neutral line to the ground wire. All three of these modes should be in the surge suppression system you are using.

Max Surge Current Capacity (MSCC)

The MSCC is the amount of power spikes (measured in Kiloampere, kA) a device can handle. The higher the max surge current capacity rating, the more significant power spikes the device can handle. This won’t ever be high enough to protect against lightning strikes, direct or nearby strikes are too powerful for any surge suppression device.

Short Circuit Current Rating (SCCR)

Short circuits cause surges on different lines than regular surges. That is why there is a separate rating for the short circuit current rating. The SCCR measures the amount of energy the device can withstand and effectively dissipate from a short circuit surge.

Max Continuous Operating Voltage (MCOV)

When measuring the line voltage (Line to Line, LL, or Line to Neutral, LN), the rating should always be higher than the demand. The minimum rating should be 115-120%, which is good enough for most installations.

Number, Size & Quality of MOV

Metal Oxide Varistors are small devices inside the power strip or surge protector. When a surge strikes, an MOV will break. In point of use devices, the MOV can only stand a single surge. Whole-home protectors are designed to handle several surges per MOV.

The more MOVs you have, and the higher their quality, the better the surge suppression of the device will be.

NEMA Enclosure Type

We will get more detail on the NEMA enclosures further below. Basically, the NEMA enclosure is a location rating where the device is capable of being installed. There are different suitable locations based on voltage ratings, weatherproofing, etc.

Residential, for example, means the device can only be located in residential locations. The same is true for indoor, outdoor, commercial/public, restricted, and many more. You will most likely not be installing the whole home surge suppression, as this is the responsibility of the power company. However, it is wise to know the ratings and NEMA enclosure types being used.

Absorption Rating

The absorption rating is a measure of the energy, measured in joules, being used by the device before it fails. The higher the number of joules in the device, the better the device will protect. In contrast, the lower the absorption rating, the better.

When looking at these numbers, keep in mind you want more joules and a low absorption rate.

UL Rating

The Underwriters Laboratories organization lists criteria that electronic equipment must meet. For surge suppressors and protectors, the criteria list is UL 1449. The devices must meet or exceed the minimum standards outlined by UL. When tested, if they pass, UL will issue a rating sticker that is affixed to each product and on all packaging.

Price & Warranty

The cost of the device will come into play as well. It is something to consider, especially if you are purchasing a whole-home system. Prices can grow based on demand even if the surge protection isn’t as good as a lower-cost system.

Be sure to check out the warranties. Some will have demands you must meet, such as proof of purchase retention, registration, or even professional installation. Ensure you can meet the requirements for fulfilling the warranty.

7 AC Surge Protector Reviewed

Now, the good part. Let’s take a look at the 7 best AC surge protectors, reviewed, and rated for your convenience. Below are the best rated surge protectors in their specific category. Find the best option for you.

1. Intermatic AG3000

Our Top Pick
Modes of ProtectionL-G, L-L, L-N
UL RatingUL 1449 4th Gen
SPD TypeType 1, Type 2
SCCR100 kA
MCOVL-N: 150V / L-L: 300V
Warranty3-year Warranty

If you are looking for the absolute best AC surge protector, there is none better than the Intermatic AG3000. Easily our top pick, this little device functions as both a Type 1 and Type 2 surge protector and can be wired in less than half an hour.

It meets all NEC and UL 1449 criteria and features all three protection modes. On top of that, you get a lot of MCOVs on both the line to neutral and line to line protections. I suppose you want more convincing, though.

The Intermatic AG3000 comes with a 3-year, $75,000 protection warranty and includes protection against residual lightening. With this device installed, you won’t have to worry about line noise, AC brownouts, or digital board failures.

It has a green light protection status to let you know it is powered on and protecting your equipment. It also pairs well with the Intermatic Compressor Defender for use on your condenser unit or heat pump.

When all things are considered, there is nothing better for your residential or light commercial HVAC system. The AG3000 covers them all and does so in a highly reputable and durable manner. You won’t be disappointed.


  • Functions as both a Type 1 and Type 2 surge protector
  • 3-year, $75,000 warranty
  • 300 Line to Line MCOVs


  • May require professional installation


Best Type 2 AC Power Surge Protector
Modes of ProtectionL-G, L-L, L-N
UL RatingUL 1449 3rd Gen
SPD TypeType 2
MCOVL-N: 150V / L-G: 150V / L-L: 300V
WarrantyLimited lifetime warranty

Type 2 AC surge protectors give you peace of mind on your side of the service line. The best Type 2 AC surge protector is the Eaton CHSPT2-Ultra. This device may require professional installation if you don’t know your way around a breaker panel.

The device is hard-wired in with 4 lead wires. It uses all three modes of protection and has MCOV of at least 150 volts for each line (the Line to Line MCOV is 300v). This is more than 115% for most residential systems.

While it isn’t designed to be installed on an internal circuit breaker panel, it can be installed in an RV or motorhome. The protection it offers is outstanding in the field and backed by Eaton with a limited lifetime warranty. There are restrictions to the warranty, though, so make sure you read all the fine print and understand the warranty.

After installation, you will have to LED indicators to let you know it is powered on and protecting. Both lights must be illuminated for proper protection. With 22 kA SCCR, your AC system is safe against most surges, spikes, sags, and brownouts.

Add in a Type 1 or Type 3 protector for your HVAC system and you won’t experience any surge worries for the life of your system. A great buy at any price, the cost is lower than most Type 2 SPDs, with more protection inside.


  • UL 1449 certified
  • Easily installs in RVs and motorhomes
  • Over 115% MCOV for most applications


  • May require professional installation
  • Should not be used on interior breaker panels.

3. Leviton 51120-1

Best Air Conditioner Surge Protector Panel
Modes of ProtectionL-G, L-L, L-N
UL RatingUL 1449
SPD TypeType 2
MCOVL-N: 150V / L-L: 300V
WarrantyLimited Lifetime Warranty

If you are looking for building protection, the best air conditions surge protection panel is the Leviton 51120-1. This panel protects 2 lines using Type 2 protection status. Bright panel LED indicators show you that protection is enabled.

We advise professional installation from a certified electrician. The Line–Neutral voltage must be tested before installation. If the measurements aren’t sufficient, the panel won’t do you any good. For residential and most light commercial applications, though, this panel will do more than suffice.

The UL 1449 certified panel comes with a limited lifetime warranty. However, you should note that labor to remove the panel and shipping costs are your responsibility, according to the warranty. You should always call Leviton to explain the problem and make sure the panel needs repair or replacement before paying for panel removal.

The NEMA 1 enclosure offers standard J-Box metal enclosures and is rated for indoor use only. You should avoid any plans to mount this on the exterior of the home. The panel is not watertight, and any moisture inside can void the warranty or cause system failure.


  • Offers all three modes of protection
  • UL 1449 certified with NEMA 1 enclosure
  • Ideal for 2-line installatons


  • Must be mounted indoors only
  • Professional installation required

4. Siemens FS140

Best Whole House Surge Protector
Modes of ProtectionL-G, L-L, L-N
UL RatingUL/ cUL 1449
SPD TypeType 2
SCCR140 kA
MCOVL-N: 150V / L-G: 150V / L-L: 300V

Siemens brings you the FS140 (First Surge, 140 kA) whole home SPD. When you want the best whole house surge protector, look no further. Not only will this 4-line SPD protect your entire home, but it also has one of the highest SCCR ratings to help prevent damage from power grid switches and residual lightening.

The one downside to this SPD is that a DIY install can (though not always) void the warranty. The FS140 is in a NEMA 4 enclosure, so it is suited for mounting outdoors or directly in the external breaker panel. Before they install it, the Line to Neutral voltage needs to be tested to ensure proper power and voltage demands are exceeded.

You also get a 10-year warranty on the device, which should cover most of the warranty period of your HVAC system, especially if it is preinstalled and a year or two old. The enclosure is rated for four lines and will show you the connectivity and surge suppression with LED indicators. When the LEDs flash red, maintenance on the device is needed, and there is an audible alert and flashing lights when a surge has caused a problem. You will always know the status of your system with the Siemens FS140.


  • Can be mounted in a panel or outdoors (NEMA 4 rated enclosure)
  • Audible alerts when something is wrong
  • Protects against power grid and residual lightning surges
  • High SCCR for maximum protection


  • DIY install can void warranty
  • More expensive than other whole-home devices

5. Intermatic Smart Guard IG2240-IMSK

Top of the Range
Modes of ProtectionL1-N, L2-N, L1-G, L2-G, N-G, L1-L2
UL RatingUL 1449 3rd Gen
SPD TypeType 1
MCOVL-N: 150V / L-G: 150V / L-L: 300V
Warranty10-years, $50,000

With a Type 1 metal enclosure, rated for indoor use, the Intermatic Smart Guard is the top of the range when it comes to whole house protection. With a total of 6 protection modes, you can install this device and never worry about your expensive equipment again.

Not only is the installation quite simple, but instead of a complete box SPD, the Smart Guard uses iModules, which suppress surges on their lines. There are three iModules per box (2 lines each), which can be replaced individually when they burn out.

The innovative TPMOV (Tamper-Proof Metal Oxide Varistors) will only open when inserted. You no longer need to change out an entire box if one surge takes out an iModule. There is also a power disconnect (2-pole 50 Amp) for quick access and iModule replacement.

Each iModule has LED indicators to let you know of protection status or if you need to replace them. The perfect complement to your smart home is the Intermatic Smart Guard. You can continue to use Type 3 SPDs in the home at the point of use, but with the IG2240-IMSK, you won’t need to worry about anything else for at least 10 years.


  • iModules are easy to replace and tamper-proof
  • Quick-disconnect means no more messing with breakers or circuit lines.
  • 6 total protection modes


  • DIY install is possible but not recommended.
  • Only 10 kA SCCR rated

6. Pipeman’s Installation Solution

Best Cheap AC Surge Protector
Modes of ProtectionL-L
UL RatingNone
SPD TypeType 3
SCCR1.5 kA

Cheap surge protection doesn’t mean it doesn’t work. The best cheap AC surge protector is the Pipeman’s Installation Solution 220-volt Type 3 SPD. There are a few things to be concerned about, though, so let’s get those out of the way.

First, the unit is not UL certified. This doesn’t mean it doesn’t meet the requirements, just that it hasn’t been passed through for certification. Second, it doesn’t come with a standard warranty. If you purchase through Amazon and are a Prime member, you can get free returns, but they do not accept replacements for damage.

Finally, this is designed only for low wattage systems (Air conditioners, refrigerators) that run on 220 volts. It will not work for dryers or heaters. What you need to know is that it works. For less than $20, your AC will be protected from a power surge.

The fuse-style Type 3 unit will blow quickly when a surge happens. This breaks the device but prevents the surge from getting to your AC system. It is a small price to pay to protect much more expensive equipment, making Pipeman’s the best 220v surge protector for air conditioners.


  • Protects low amp devices (15 amps)
  • No installation, just plug it in
  • Quick pop fuse prevents surge in voltage from getting to AC


  • One-time use only
  • Not UL certified

7. Belkin 12-Outlet Power Strip

Best Power Strip Surge Protector
Modes of ProtectionL-G, L-L
UL RatingUL 1449
SPD TypeType 3
SCCR7.5 kA
MCOVL-G: 150V / L-L: 300V
WarrantyLimited Lifetime Warranty

Belkin is a household name and a trusted one at that. The Belkin 12-outlet power strip adds functionality to your outlet while providing Type 3 surge protection to your devices. The overall design is meant for multiple electronics such as your computer station, or your entertainment center electronics.

However, because of the ratings (UL 1449, 75,000 amps), it will protect your AC as well. You need to ensure that you plug nothing else in, though, as your AC will max out the amps of the device as it is AC rated for 15 amps.

There is cord management and a low profile to help keep it out of sight and out of the way. You also get LED indicators of power, suppression, and operation. With Line–Ground and Line–Line protection modes, it will withstand a few years’ worth of power spikes. The 3940-joule rating will eventually wear out, but for most areas across the US, this will be between 3 and 5 years.

The best power strip surge protector gives you 12 outlets, and a limited lifetime warranty. The fine print of the warranty is easy to follow, and there aren’t many restrictions on the claim process.


  • Over 3900 joules of protection with over-sized MOVs
  • Limited lifetime warranty
  • UL certified (1440 4th gen)


  • Not specifically designed for air conditioners

Understanding Power Surges & Their Effects on AC Units

In the US, our electrical devices (i.e., TVs, computers, refrigerators, and air conditioners) are designed to run on 120 volts, 60 hertz, single phase, alternating current. What this means is that the electricity supplied to the device comes in waves. It works similar to a heartbeat where the voltage drops to 0 and peaks at about 169 volts.

A power surge is an electrical interference that causes the peak to far exceed 169 volts. When this happens, the extra power, or surge, can cause the device to burn its electrical board or other electronics and stop working. On your AC, the damage can reach the control board, the capacitor, the contactor relay switch, or even the compressor.

Internal surges can also damage the evaporator fan, relays, and thermostat. Depending on the type of surge, various damage results are observed. You may find that the AC creates line noise or fluctuations in the power line when there is a draw. This can cause house brownouts or power dips, and the AC attempts to pull enough power from the house to turn on.

Whenever the surge and resulting damage are prolonged or not protected, further damage usually follows. More damage results in more repairs and expenses for you. Something you want to avoid.

3 Common Types of Surge Protector Devices

There are five types of surge protector devices (SPDs). They are classified and categorized by the National Electrical Code (NEC) and UL 1449 criteria. Of all the types listed, there are three that you need to be concerned with.

Type 1: Service Entrance Surge Protectors

Type 1 SPDs are known as service entrance protectors. These are installed at the location where electricity enters the home, known as the service side. The main job of a Type 1 is to protect against outside surges caused by things like power grid switching, lightning and power line shorts. Most of these are the responsibility and property of the power company.

Type 2: Whole Home Surge Protectors

Type 2 SPDs, like Type 1’s, are permanent fixtures. They also protect against residual lightning, surges from power drains (like your AC kicking on), and other surges that come from inside the home. These are mounted opposite of the Type 1 SPDs on the load side of the service connection.

Type 3: Receptacle Surge Protectors

Type 3 SPDs are also known as Point of Use devices. These are your power strips, outlet protectors, and other removable devices that you place between the power outlet and the device being powered. These protect against any surge that makes it through the other two options and help regulate the flow of energy through your home wiring to the devices they power.

Tips for Installing and Operating HVAC Surge Protectors

Surge Protector Power Line


Before installing your new HVAC surge protector, you need to know where it will be installed, how to install it, and what safety precautions you need to take.

Air conditioners rely on and use 220 volts of electricity. This is enough voltage to cause severe injuries or even death.

Always remove power to the AC system before you begin.

Installation of the AC surge protectors isn’t a complicated process, but you need to take your time doing so.

Make sure you follow the instructions and perform each step without skipping ahead. Always secure your power wires and adequately mount the surge protector in a designated area.

For a quick overview of the process, you can check out this video to see how it is done:

People Also Ask (FAQs)

Do I really need multiple types of surge protection installed for my HVAC systems?

Multiple types of surge protection is actually a warranted issue in today’s technologically advanced world. Since most HVAC systems are no longer purely mechanical, they rely on computer parts and digital components to operate correctly. Protecting these components is vital to the longevity of the system and any warranties they carry.

What is voltage protection rating?

According to UL 1449, the voltage protection rating (VPR) is the rating of the device on how much voltage it allows to go through to the connected device. In terms of the VPR, a lower number is better.

What is the difference between a surge protector vs. power strip protector?

In short, the difference between a surge protector and a power strip is that a power strip doesn’t protect the devices connected to it. A power strip is less expensive and only facilitates using more devices per outlet. A surge protector, on the other hand, protects the connected devices from power surges in the home.

Can you use a surge protector with an air conditioner window unit?

It is possible as long as the ratings of the surge protector exceed the requirements of the window unit. If the ratings are the same or the surge protector’s ratings are lower, the surge protector will overheat, burn up, and could start a fire. Most window and portable air conditioners have built-in surge protection already.

How do I measure or test the effectiveness of a surge protector?

There isn’t a reliable (or inexpensive) method of testing a surge protector. The joules rating of your surge protector also acts as its lifespan. Higher joules are better, but the absorption is cumulative. This means that as time goes on, minor surges add up to killing your surge protection. After it uses the joules, the surge protector turns into a power strip and no longer protects your equipment. The average replacement expectancy of a 1000 joule surge protector is 24 to 36 months.

Can I use a power strip surge protector outside?

There are a few power strip protectors rated for exterior use, but it is never a good idea. Damp conditions, moisture, and rain will get into the power strip and can cause a lot of damage. Water and electricity never mix. Instead, use the grounded outlet on the outside of your home and unplug when not in use.

How many joules is a good surge protector?

A lot will depend on what you are plugging into the surge protector. The more joules, the better protection you will get. The minimum for most of today’s applications (televisions, computers, etc.) is at least 600 joules. 800 or higher is recommended, though.

Will a surge protector in the panel box protect everything in my home?

Yes. A panel box surge protector will protect all the lines feeding into the home. However, internal surges, appliance overloads, brownouts, and residual lightning power will not be protected against.


As you can see, there is a lot to consider before you buy your next surge protection device. You have to consider the device type, joules, and VPR ratings and make sure the protector conforms to UL 1449.

If you have any doubts about protecting your HVAC system or which model to go with, we highly recommend you start with the Intermatic AG3000, our top pick for the best AC surge protector.