Although they can look robust, HVAC systems are usually simple as they have just a few components that are in charge of regulating the room temperature.
Our guide to the best HVAC capacitors will help you understand why these parts are so important for the seamless operation of cooling and heating systems.
In fact, using an HVAC system without these components is impossible because your home’s electrical system can’t provide enough power to start the compressor or the fan.
Consequently, capacitors are spread throughout the system, and they provide complementary starting power to its key components.
Capacitors are also the least durable part of any HVAC system, which is why they need to be replaced more often than other parts of the system. Thus, in this guide, we’re going to provide you with the information you need to find a replacement for your HVAC capacitor.
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At a Glance – The 5 Best HVAC Capacitors
| Model | Capacitor type | Capacitance | Price |
| TemCo RC0049 | Fan only | 7.5 MFD | $ |
| MaxRun MR-35 | Compressor and fan | 35/5 MFD | $$ |
| PowerWell PW-70 | Condenser | 70/7.5 MFD | $$$ |
| Bojack BJ-CVP | Compressor and fan | 12.5 MFD | $$ |
| Genteq C3355R | Dual run (Compressor and fan) | 35.5/5 MFD | $ |
This Capacitor is rated for 440 Volts which means it will work at 370 or 440 VAC. A dual run capacitor, such as this 35/5, combines two capacitors into one unit. It will power a compressor motor and a fan motor, and has three terminals on the top.
A dual "run capacitor" supports two electric motors, such as a fan motor and a compressor. Round dual run capacitors are used to start and run the unit more efficient.
Selection Criteria
The HVAC capacitor market is dominated by a handful of brands, but even so not every model produced by industry-leading companies offers a high level of quality and versatility. During the selection process we’ve utilized a number of parameters to pick the best capacitor replacement parts for your HVAC.
Let’s take a look at the selection criteria we used to select the best HVAC capacitors on the market:
- Capacitor compatibility – Our selection of capacitors includes single-run models tasked with sending extra power to the condenser or the fan motor and dual-run options capable of powering a compressor and motor fan simultaneously.
- Part availability – Our list of the best HVAC capacitors includes models that can be found easily either online or in a local HVAC part shop. You need to check if any of these capacitors are compatible with your HVAC system before purchasing them.
- Customer reviews – Previous user experiences played a major role in our selection process, as we only included models that got positive reviews from customers.
- Price – Despite the fact that capacitors are not expensive, the price of specific models still influenced our selection process. Most models we’ve included in this article are budget-friendly and you won’t have to spend more than $50 to get them.
What Does a Capacitor Do?
These devices are simple in design as they are composed of two metal plates that serve as electrical conductors. These plates are separated by a dielectric, non-conductive material that determines the capacitor’s capacitance.
The capacitance value is measured in microfarads (MFD), and it indicates the ratio between the electric charge on both conductors and voltage. The capacitor’s capacitance depends on the size of conductors and the distance between them and the dielectric material.
These devices store electrical charge and release it once electricity that powers an AC system goes through them to generate enough energy to start the unit’s compressor, fan, and condenser.
This process is repeated every time the HVAC system begins a new cycle, which causes this part to wear out. An average HVAC system has more than just a start capacitor, as the compressor, indoor and outdoor fan motors all have their separate capacitors.
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Types of HVAC Capacitors
HVAC units use three types of capacitors that are located at different positions throughout the system.
Start Capacitor
This type of capacitor is based on the outdoor component of heat pumps and similar split systems. Their role is to supply the compressor with additional power and help the system commence the cooling or the heating cycle as quickly as possible.
Besides regular start capacitors, some HVAC systems can be equipped with a Super Boost capacitor capable of generating a vast amount of torque. It is worth pointing out that both types of start capacitors are more common on HVAC systems designed for industrial settings.
Dual Run Capacitor
Commonly featured on outdoor components of cooling systems, dual run capacitors supply power to compressor and fan motors. Their size and shape vary from model to model, so their compatibility with a particular HVAC system largely depends on their dimensions and shape.
In addition, most dual-run capacitors can run at 370V and 440V, which enables you to use them with systems that run on 370V or 440V.
Single Run Capacitor
This capacitor type is usually utilized to provide additional starting power to furnace blower motors. Unfortunately, even though it is one of the essential components of heating systems, a single-run capacitor isn’t very durable.
This type of capacitor can also be used on cooling systems to supply a condenser fan motor with additional power. Go through our guide to furnace types to learn more about how these devices and heating systems work.
Energy Storage Capacity
Capacitance shows you how much energy a capacitor can store. This value depends on the capacitor type, and it can vary from 1.5MFD to 70MFD on single-run capacitors. A start capacitor’s energy storage potential is significantly higher, and it ranges from 70MFD to 200MFD.
Dual run capacitors can have two capacitance values; the higher value indicates the amount of power that goes into the compressor motor, while the lower value shows you how much energy is allocated to the fan motor.
HVAC systems come with built-in capacitors, and in case one or more of the factory breaks down, and you need to replace them, you should make sure that the aftermarket parts have the same capacitance as the original parts.
Installing an undersized capacitor in an HVAC system will cause damage to the system as the compressor and fan motors will have to work harder every time you start the system.
On the other hand, a capacitor that is too powerful for an HVAC system will send too much electricity to the motors of these components.
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Why Do HVAC Capacitors Break Down?
Capacitors are the least durable component of an HVAC system. If the system’s cooling or heating capacities decline suddenly, the capacitor is most likely to blame. Let’s take a look at some of the most common reasons why these parts fail.
- Daily wear and tear – The more you use your HVAC system, the more stress you put on the capacitors. These HVAC system components are designed to last for two decades, but they tend to wear out much faster if the system is used extensively.
- Prolonged heat exposure – High temperatures wear out capacitors over time, as heat damages the dielectric and the conductors. The best way to protect a capacitor from heat is to cover the unit’s outdoor component during extremely hot days.
- Inadequate voltage rating – Failing to match the capacitor’s voltage rating with the requirements of the HVAC system will shorten the capacitor’s lifespan. Besides, installing a capacitor that doesn’t match the system’s voltage requirements is likely to damage the compressor and other components.
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Replacing an Old HVAC Capacitor
You don’t need advanced technical skills to replace a capacitor, but determining which system’s capacitors has failed can be an overwhelming task for someone who’s not familiar with how HVAC systems work.
To install a new capacitor, you first need to remove an old one that broke down even if faulty; these parts can still contain some electrical charge, which is the reason why it is paramount to make sure that the capacitor doesn’t contain a residual charge.
Also, the capacitor you want to install must have identical features to the one you’re replacing. That’s why it’s much better to hire a professional technician to change the capacitor for you than to risk causing damage to the entire HVAC system.
Besides, capacitors aren’t expensive as most models cost between $10 and $80, so you won’t spend more than $200 to repair the system if you decide to hire a technician. Go through our guide to the best HVAC tools if you want to replace an old HVAC capacitor on your own.
The Most Important Factors to Consider While Choosing a New HVAC Capacitor
Searching for an aftermarket capacitor isn’t a complex process if you know which capacitor type and model your HVAC system is using. That’s why you should go through the unit’s manual before you start looking for a new capacitor.
There’s an abundance of options to choose from, so finding the model that matches the system’s specifications shouldn’t be too difficult. Even so, a number of factors can affect your decision to choose one model over another.
We’ve shortlisted some of the most important factors to help you find the best capacitor for your HVAC system, so let’s take a closer look at them.
Shape and Size
Capacitors vary in shapes and sizes, so before you start searching for a replacement, you must first find out the exact shape and dimensions of the capacitor currently installed in your HVAC system. A capacitor can either be oval or round, and its length is usually between two and six inches.
Even though oval and round models can be used interchangeably, this is only possible if there is enough room to install a bulkier capacitor.
Single or Dual Run Capacitors
Finding out which type of capacitor you need is of utmost importance because you can’t replace a single-run capacitor with a dual-run capacitor.
That’s why you need to determine which components of the HVAC system receive the additional power from the capacitor and then get a model that can allocate the same amount of power to these components.
In addition, a single-run capacitor is usually paired with a condenser, while dual-run capacitors commonly supply power to the compressor and fan motors.
Voltage Rating
This rating shows the maximum voltage that can pass through a capacitor. Older versions of capacitors can only supply 370VAC of power, while newer models are compatible with systems that run on 370V and 440V.
Installing a capacitor with a 440V voltage capacity on HVAC requiring only 370V to start won’t have considerable consequences on the system. Even so, it is advisable to match the capacitor’s voltage rating to the system’s requirements.
The Part Manufacturer
The quality of the capacitor’s parts determines how long you will be able to use them. That’s why you should opt for a model produced by a well-known and reliable brand, even if it is more expensive than a capacitor made by an unknown brand.
TemCo, MaxRun, or PowerWell are some of the industry-leading brands that manufacture capacitors designed to last up to two decades.
In addition, HVAC manufacturers like Honeywell or Lennox also produce capacitors, so getting a model made by these brands might be a good idea if you already have a furnace or a heat pump manufactured by the same brand.
The advantages of HVAC capacitors
Simple Replacement Process
Installing a new capacitor doesn’t take much time or effort, and an experienced DIYer can complete this task. Hence, you won’t have to spend money on repairing your HVAC system if you have the right tools to complete the job.
Low Cost
Even the most expensive capacitor models can be purchased for less than $100, which makes these components of HVAC systems very affordable. You won’t have to spend more than $50 on a new capacitor for your heating or cooling system, in most cases.
Long Lifespan
Despite the fact that capacitor is the least durable part of an HVAC system, its lifespan is still measured in years rather than months. Some manufacturers even claim that their products can last for 60.000 hours of runtime, which suggests that you can use them for 10 to 20 years.
The Disadvantages Of HVAC Capacitors
Low Heat Tolerance
You must protect the outdoor component of your HVAC system from the heat in order to prevent the failure of the capacitor. This can be difficult if you live in a warm climate region where temperatures over 90F are common.
Top 5 HVAC Capacitors
TemCo RC0049 – The Best Fan Only Capacitor
TemCo RC0049 is a replacement part for single-phase and three-phase motors, which makes it suitable for most fan motors featured on HVAC systems. This part can supply 370V or 440V to the component it is powering, and it is compatible with both old and new heat pumps and furnaces.
The capacitor’s capacitance is limited to just 7.5MFD, which is the reason why it can’t store large amounts of energy. The manufacturer offers a 5-year warranty that ensures you can replace the part for free if it breaks down during that period.
Pros
- Compatible with a wide range of fan motors
- Oval and round versions of the capacitor are available
- The durable casing features a steel cap
- Equipped with quadruple QST terminals
Cons
- Low energy storage capacity
- Not suitable for all types of HVAC systems
TEMCo's AC Electric Motor Run Capacitors are designed specifically for the replacement of OEM single and three-phase motor capacitors. These units are housed in aluminum casing with a steel cap.
MaxRun MR-35 – The Best Dual Run Capacitor
As one of the most durable dual-run capacitors on the market, the MaxRun MR-35 can remain operational for 60.000 hours. You can use this part to supply additional power to the HVAC system’s compressor and fan motors.
This capacitor sends 35MFD to the compressor and 5MFDs to the fan motor, ensuring that both components function seamlessly. It also has advanced safety features that include an anti-explosion switch that protects the capacitor and the HVAC system from damage.
Pros
- 5-year warranty
- Supplies power to the compressor and fan motor simultaneously
- Excellent safety features
- Easy installation process
Cons
- An oval version of the capacitor isn’t available
- Limited compatibility
This Capacitor is rated for 440 Volts which means it will work at 370 or 440 VAC. A dual run capacitor, such as this 35/5, combines two capacitors into one unit. It will power a compressor motor and a fan motor, and has three terminals on the top.
PowerWell PW-70 – The Best Condenser Capacitor
You can use the PowerWell PW-70 as a replacement part for a wide range of dual-run capacitors. This part can run at 370V or 440V depending on the system’s requirements, and it supplies the compressor and fan motor with 70+7.5MFD of power.
This round capacitor is 5-inches tall, so it might be too large to fit on some types of HVAC systems. The oval version of the capacitor isn’t available, and you must check if you can use it on your furnace or heat pump.
Pros
- Serves as a replacement for a large number of factory dual run capacitors
- Durable construction
- High energy storage capacity
- 5-year warranty
Cons
- Tall and bulky
- More expensive than similar models
A dual "run capacitor" supports two electric motors, such as a fan motor and a compressor. Round dual run capacitors are used to start and run the unit more efficient.
Bojack BJ-CVP – The Best Commercial-Grade HVAC Capacitor
In case your HVAC system’s compressor and fan motor have stopped working, you can replace the capacitor that powered them with the Bojack BJ-CVP. The dual-run capacitor can operate at either 370V or 440V, depending on the system’s requirements.
Bojack’s model can store up to 12.5MFD of energy, and it can be used as a replacement for numerous original parts. The capacitor’s operating range spans from -104F to +158F, and moderate exposure to heat can’t damage it.
Pros
- Compatible with a wide range of ACs and heat pumps
- Operates at high and low temperatures
- 10.000AFC safety rating
- Durable and reliable
Cons
- Warranty information isn’t available
- Moderate energy storage capacity
Oval run capacitor can be used to substitute round shape one with the same MFD and volt specs.
Genteq C3355R – The Most Affordable HVAC Capacitor
Besides being one of the most affordable capacitors on the market, the Genteq C335 is also one of the most durable HVAC capacitors you can get. However, this part is only compatible with HVAC systems that run on 370V, and you can’t use them on 440V systems.
The dual-run capacitor can send up to 35MFD of extra power to the compressor and 5MFD to the fan motor. The C3355R capacitor is compact and lightweight, so you won’t have too much trouble fitting it on your HVAC system.
Pros
- Good capacitance
- Excellent heat resistance
- Low price
- Easy installation process
Cons
- Limited compatibility
- No safety features
Genet Motor Run Capacitors replace / supersede old obsolete GE Industrial capacitors and are considered the most reliable capacitor available.
Frequently asked questions about HVAC capacitors
Question: How to Know if an HVAC Capacitor is Failing?
Answer: The compressor and other components of the HVAC system are going to stop functioning properly if the capacitor that provides them with additional power breaks down.
Question: Do I Have to Perform Maintenance Checks of HVAC Capacitors?
Answer: HVAC capacitors don’t require maintenance checks unless one or more system components aren’t operating at their full capacity.
Question: Do I Have to Get the Same HVAC Capacitor as the One I am Replacing?
Answer: Getting an identical HVAC capacitor like the one you want to replace isn’t necessary, as long as you choose the model that is compatible with your HVAC system.
Question: Can I Fix a Broken HVAC Capacitor?
Answer: Fixing a capacitor after it breaks down isn’t possible, and your only option is to replace it.
Our Verdict: How to Find the Best Capacitor for Your HVAC System?
Even though capacitors aren’t the first thing that comes to mind when HVAC systems are mentioned, using an AC, a furnace, or a heat pump without a capacitor isn’t possible.
All HVAC systems come with built-in capacitors, and if one or more of the unit’s capacitors fail, the best course of action is to replace them with an identical model. Hence, the best capacitor for your HVAC system is the one recommended by the manufacturer.
Dual run capacitors like the MaxRun MR-35 or the PowerWell PW-70 can be reliable replacement solutions, but only if they’re compatible with the HVAC system, you’re using. Was this guide to the best HVAC capacitors useful?
This Capacitor is rated for 440 Volts which means it will work at 370 or 440 VAC. A dual run capacitor, such as this 35/5, combines two capacitors into one unit. It will power a compressor motor and a fan motor, and has three terminals on the top.
A dual "run capacitor" supports two electric motors, such as a fan motor and a compressor. Round dual run capacitors are used to start and run the unit more efficient.
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