How Much Is A Limit Switch For A Furnace? A Complete Guide

Rima Chatterjee

What Is A Limit Switch For A Furnace?

How Much Is A Limit Switch For A Furnace

To understand what a limit switch for a furnace is, and how it works to ensure your furnace operates safely and efficiently, let me break it down for you. Firstly, I’ll discuss the definition of a limit switch for a furnace. After that, we’ll talk about how it works and the different types of limit switches that are available for furnaces.

Definition of a Limit Switch for a Furnace.

A limit switch for a furnace is a safety device with an important job. It watches the temperature of the furnace. If it gets too hot, the switch will shut off the gas or oil burner. That way, it prevents the furnace from overheating and starting a fire.

The switch works together with other safety devices. This way, the furnace will turn off if any of the devices fail. It’s just one of many parts that keep your home warm and safe.

Not all furnaces have a limit switch. But, many newer ones do. To be sure, check the owner’s manual or ask a professional.

Recently, my friend had an issue with their limit switch. It was faulty, so the furnace got too hot. But, they caught it before it caused serious damage. This shows how these safety devices are important for preventing disasters.

If a limit switch for a furnace had a superpower, it would be protecting your home from becoming a blazing inferno!

How it Works.

Limit switches are vital safety devices that control electrical functions in furnaces.

  •  They act as shut-off mechanisms when they detect an increase in temperature. This protects your home and stops any furnace damage.
  • The switches come in different sizes and shapes, designed for specific furnaces. They communicate with other heating system elements and work by bending when heat is applied. This opens contacts in the switch to signal equipment shut-down or activation.

Pro Tip: It’s crucial to replace or service limit switches each year. This helps prevent any possible hazards. 

So, don’t be fooled by the name, limit switches are a furnace buffet of safety choices.

Types of Limit Switches for a Furnace.

Limit switches are a must-have safety feature in furnaces. Different types offer various functionality, voltage rating, and thermal resistance. 

Here’s a quick overview:

TypeFunctionalityVoltage RatingThermal Resistance
Snap DiscOpens/closes @ set temp120V-240V AC/DCUp to 350°F
Bi-metal switchWarps when heatedUp to 600V AC/DCUp to 350°F – 700°F
Mercury switchElectric current flowsUp to 300V AC/DCUp to 350°F – 700°F

Adjustable limit switches are also available; allowing you to specify the temperature range. If you don’t know which one you need, speak to an HVAC tech. Safety first!

Look out for these signs if your limit switch is faulty.

Signs Of A Faulty Limit Switch In A Furnace.

To quickly spot signs of a faulty limit switch in your furnace, turn to this section with its insightful sub-sections, Symptoms of a Bad Limit Switch and Effects of a Faulty Limit Switch

These subsections will provide an understanding of the common symptoms and effects of a malfunctioning limit switch on your furnace’s operation and safety.

Symptoms of a Bad Limit Switch.

Are you feeling a chill in your home? It could be a sign of a malfunctioning limit switch in your furnace! 

Here are some common indicators of a bad limit switch:

  • Uneven Heating? Check.
  • Constant cycling? Check.
  • The furnace won’t turn on? Check.
  • Persistent Blower Fan? Check.
  • Lack of warm air blows out? Check.

If you experience any of these signs, it’s important to get it checked right away by an expert. Delaying maintenance can lead to costly and unsafe circumstances later on. So, if you spot any of these issues with your heating equipment, call in the professionals ASAP.

 You don’t want to be stuck shivering through the winter because of a broken limit switch!

Effects of a Faulty Limit Switch.

A faulty limit switch in a furnace can cause major problems, such as:

  • No heat.
  • Not reaching the desired temperature.
  • Blower motor running continuously or shutting off too soon.
  • Blocked air filters, clogged burners, or malfunctioning thermostats.

It is essential to detect and fix these issues in time. Otherwise, you may face higher repair costs. Regular maintenance will keep your heating system functioning properly during winter and maintain a comfortable indoor temperature.

An example of how a faulty limit switch can lead to a disaster is the incident of a homeowner who smelled gas while adjusting his thermostat manually. Due to no routine maintenance, the technician found that the furnace’s gas valve control circuit was transmitting electricity even when no flames were present in the burners!

But, the homeowners’ immediate action with professional help avoided a major disaster. 

So, investing in limit switch repair early on is the way to go, unless you want to pay for a frozen winter with your frostbitten fingers!

How Much Does a Limit Switch for a Furnace Cost?

To find out how much a limit switch for your furnace will cost, you need to consider different factors as solutions with average costs and ways to save money. In this section, we will explore these sub-sections in detail. 

First, we will discuss the factors that affect the cost of a furnace limit switch, followed by the average cost of the switch you can expect. Lastly, we will provide ways to save money when purchasing a limit switch for your furnace to keep your home comfortable and safe.

Factors that Affect the Cost of a Furnace Limit Switch.

A furnace limit switch is an essential element to guarantee the safety and performance of your heating system. 

Let’s talk about these factors in detail. The  cost of a furnace limit switch varies depending on several factors, such as;

  • Brand: Different brands offer various prices for their limit switches. Notoriously expensive brands usually cost more than others.
  • Type: Several types of limit switches can be used in furnaces. Each one has different pricing, depending on its efficiency and ease of installation.
  • Compatibility: Before purchasing, it’s important to make sure the limit switch is compatible with your furnace’s make and model.
  • Size: Prices may vary according to the size needed for different furnaces.

Getting a skilled HVAC technician to install the limit switch will ensure proper installation and prevent damage or mistakes during the process.

 Replacing the limit switch before the furnace breaks down can help save money, compared to waiting until it’s too late.

Are you prepared to feel the heat where your wallet is? The average cost of a furnace limit switch is enough to make you want to hide until spring!

Average Cost of a Limit Switch for a Furnace.

When it comes to the cost of a limit switch for a furnace, it can vary. Nationally, it ranges from $50 to $250. But, pricey models or customized switches may be more.

The table below gives a better idea:

TypePrice Range
Manual Reset$50-$100
Electronic Reset$100-$200

Besides the switch itself, there may be installation fees. You can pay for professional help or do it yourself.

If your furnace keeps shutting off, it’s probably a malfunctioning limit switch. Get an HVAC technician to check it and save money.

Ways to Save Money on a Furnace Limit Switch.

Limit switches are key components of a furnace, ensuring its safety and efficient operation. A faulty limit switch can make the furnace shut down or cause damage.

To save money on replacing a limit switch, try these three tips:

  • Check your warranty. You could get a free or discounted replacement part.
  • Compare prices. Look for affordable options.
  • Perform regular maintenance. This can help extend the life of your limit switch.

Buying used or refurbished parts may save money, but be aware that this may not be safe. Besides, investing in annual inspections done by certified HVAC technicians. These will identify potential problems before they worsen, increasing the life of your heating system.

Remember: Quality is more important than price when buying replacement parts, especially limit switches that affect performance and safety.

How To Replace A Limit Switch In A Furnace.

To replace a limit switch in a furnace, you need the right tools and a clear idea of what to do. You’ll benefit from knowing the steps involved in the job, and which safety measures to take while doing it. In the upcoming sub-sections, we’ll discuss the tools you need for replacing a furnace limit switch, then walk you through the steps involved in the process, and finally touch on the critical safety measures you should follow during the repair.

Tools Required for Replacing a Furnace Limit Switch.

Replace your furnace’s limit switch yourself! 

You’ll need:

  1. Flathead screwdriver.
  2. Phillips screwdriver.
  3. Nitrite gloves.
  4. New limit switch.
  5. Voltage tester.
  6. Wire stripper/cutter.

Follow these six steps and keep cozy:

  1. First, shut off the power.
  2. Remove the old limit switch with the appropriate tools.
  3. If needed, strip ½” of insulation from each wire.
  4. Connect the wires of the new limit switch.
  5. Put the screws back in place and check all connections.
  6. Switch the power back on and test it!

Choose your replacement parts wisely; refer to your furnace manual for manufacturer specifications. 

Get toasty this winter and get started today!

Steps to Replace a Limit Switch in a Furnace.

Replacing a limit switch may seem intimidating, but it doesn’t need to be!

Here’s an easy guide:

  1. Turn off the power to the furnace.
  2. Find the limit switch near the heat exchanger; it looks like a small rectangular box with wires.
  3. Disconnect the wires from the old switch.
  4. Remove the old switch and install the new one.
  5. Attach the wires to the new switch.
  6. Turn on the power and test if it’s working.

Note: Different furnaces have different procedures for replacing a limit switch, so check the manual before doing repairs. Get a replacement with similar specs to ensure proper functioning.

An HVAC tech once told a story about fixing a furnace during winter when temps were freezing. The only cause? A bad limit switch.

 They replaced it fast and saved their client without charging extra; since it was so easy!

Remember: Safety first when replacing a limit switch in your furnace; or else you might get too hot!

Safety Measures to Take When Replacing a Limit Switch.

Replacing a limit switch in your furnace? Take safety precautions.

 Here’s a step-by-step guide:

  1. Turn off the power.
  2. Disconnect thermostat wires.
  3. Release capacitor charge.
  4. Inspect surroundings.
  5. Use necessary tools.
  6. Wear protective gear.

Keep kids and pets away from the work area. Follow the manufacturer’s instructions.

Avoid leaving electrical cords or tools near open flames or heat sources. Fire hazards! James Watt created an early version of a limit switch in steam engines in 1794. Technology has advanced since then. Today’s furnaces have integrated safety features

A limit switch is like an invisible babysitter for your furnace. Keeps it from starting a fire.

Benefits Of A Functioning Limit Switch In A Furnace.

To ensure your furnace operates safely and efficiently, having a functioning limit switch is critical. A faulty limit switch can cause overheating, short-cycling, or prevent the furnace from starting altogether.

 In this section, we’ll discuss the importance of the limit switch in your furnace and its benefits. First, we’ll cover the improved efficiency of the furnace with a functioning limit switch. Then, we’ll explore how the limit switch can increase safety for your home. 

Finally, we’ll look at how the limit switch can prolong the lifespan of furnace components.

Improved Efficiency of the Furnace.

In a furnace, having a limit switch is great for efficiency. It controls the heat and stops it from getting too hot. 

Here are some benefits:

Improved energy efficiencyLimit switches stop it from overheating, saving energy.
Enhanced safetyLimit switches to turn off power if temperatures get too high, avoiding fires.
Prolongs the lifespan of the furnaceTemperature fluctuations are limited, so the furnace’s parts last longer.

Plus, you get better control over the heating cycle, with more precision and consistent firing temperatures.

Recently, an HVAC technician saw the impact of a malfunctioning limit switch. The client spent lots of money on repairs, but the real issue was their limit switch. Replacing it made the furnace run better, with fewer breakdowns.

For a safer and calmer life, get a functioning limit switch; no furnace meltdowns or mental breakdowns!

Increased Safety for the Home.

A functioning limit switch can significantly increase the safety factor for homeowners.

  •  It detects when the furnace is too hot, which could lead to fires or carbon monoxide poisoning. 
  • A limit switch prevents these catastrophic accidents from occurring by shutting off the furnace before it reaches a critical temperature.
  • It can also save money
  • If left to overheat, the furnace uses more energy than necessary. This leads to higher energy bills. But with a limit switch in place, the furnace will shut off when it reaches its designated temperature and start up again only when needed.

Studies show furnaces with functioning limit switches live longer. According to the American Society of Home Inspectors, those without limit switches face additional wear and tear due to prolonged use and overheating.

 Investing in a furnace with a functioning limit switch increases safety and extends your heating system’s lifespan.

Prolonged Lifespan of Furnace Components.

A functioning limit switch is essential for any furnace system. It regulates and monitors the furnace temperature, preventing it from going above the manufacturer’s set limit. This helps keep furnace components from overheating and getting damaged.

An operational limit switch will prolong the lifespan of your furnace parts. If temperatures go beyond normal levels, metal parts can expand too much, causing cracks and other damage. These can lead to hazardous situations like gas leaks.

Having a fully functional limit switch helps avoid costly repairs. It keeps temperatures steady and detects malfunctions early on, allowing for preventative maintenance or repair before severe damage occurs.

Don’t settle for a malfunctioning furnace. Make the switch to a functioning limit switch today!

Where To Buy A Limit Switch For A Furnace.

To find a limit switch for your furnace, you want to know where to buy them. Searching for a furnace limit switch, you’ll find various options, but we’ll discuss three of them: online retailers, local HVAC suppliers, and manufacturer direct. We’ll briefly introduce each sub-section and weigh the pros and cons of each option to assist you in making an informed purchase decision.

Online Retailers.

Online retailers are a great place to buy a limit switch for your furnace. 

Check out these top options:

  • Amazon: Offers a wide range of products, competitive prices, fast delivery, and easy returns.
  • eBay: Buy items outright or bid on them for a deal.
  • Grainger: Industrial-grade parts and equipment, with a knowledgeable support team.
  • Allied Electronics: Industrial supplies, and technical advice available.

Do research and compare prices before buying. Check customer reviews for quality assurance. Online shopping gives access to a wide selection of brands and models, but make sure you’re buying from a reliable seller.

John purchased a limit switch from Amazon, based on reviews. It was a quick and easy process; he got the part in just two days. He was pleased with his experience.

Local HVAC Suppliers.

Heading to Local HVAC Suppliers for a limit switch for your furnace?

You’ve come to the right place! Many locations are available, so you can shop close to home. Plus, they have more than just limit switches. AC systems, electric furnaces, heat pumps, and lots more!

 The knowledgeable staff can help you pick the right product. And prices are competitive, so you can save money. Customer satisfaction is a top priority. Some suppliers even offer installation services. 

Check out Ferguson Enterprises for trust and lifeworks solutions! 

Finally, don’t forget the manufacturer’s direct limit switches for smoother furnace functioning.

Manufacturer Direct.

Buying a limit switch for your furnace can be tricky. But you can get the best quality products at reasonable prices from manufacturers directly!

To help you out, we made a table of furnace manufacturers and their websites to purchase limit switches.


Each company has different limit switches to fit your needs. Check each product and compare prices before buying.

 Also, buying directly from the manufacturer is better. You’ll get quality and customer support if you need help with installation or use. 

This approach has been in use since the early 20th century when mass production started. It helps industries and consumers avoid middlemen who jack up prices. Manufacturers usually offer better deals and immediate technical support.

Don’t risk it, buy a new limit switch today so your furnace won’t become a fire hazard or an expensive paperweight!

Frequently Asked Questions

Q: What is a limit switch for a furnace?

A: A limit switch for a furnace is a safety device that monitors the temperature inside the furnace and prevents it from overheating. It is designed to shut off the furnace if the temperature exceeds a predetermined limit, ensuring safe operation.

Q: How much does a limit switch for a furnace typically cost?

A: The cost of a limit switch for a furnace can vary depending on various factors such as the brand, model, and specifications. Generally, a limit switch for a furnace can range in price from $10 to $50.

Q: Where can I purchase a limit switch for a furnace?

A: You can purchase a limit switch for a furnace from various sources. Some common options include local HVAC supply stores, online retailers specializing in furnace parts, or contacting the manufacturer directly for authorized distributors.

Q: Are there different types of limit switches available for furnaces?

A: Yes, there are different types of limit switches available for furnaces. The specific type required for your furnace will depend on the make and model. Some common types include bimetallic disc switches, mercury switches, and electronic switches. It’s important to consult the furnace’s manual or seek professional advice to ensure compatibility.

Q: Can I replace a limit switch for a furnace on my own?

A: While it is possible to replace a limit switch for a furnace on your own, it is recommended to have a professional HVAC technician perform the replacement. Furnace systems involve electrical components and safety considerations, so it’s best to ensure the replacement is done correctly to avoid any potential hazards.

Q: Should I consider hiring a professional for limit switch replacement even if I have some DIY skills?

A: Yes, it is advisable to hire a professional for limit switch replacement, even if you have some DIY skills. HVAC technicians have the expertise and knowledge to handle furnace components safely and efficiently. They can also diagnose any underlying issues and ensure the replacement is done correctly, reducing the risk of damage to the furnace or compromising its performance.


Without a working limit switch, furnaces can be dangerous and cause expensive repairs. It functions as a temp sensor and shuts off the furnace if it gets too hot. This protects against fires or carbon monoxide leaks. Plus, it turns on the blower fan to spread heat throughout your home. Investing in a quality limit switch helps your unit last longer and keeps you safe. If the furnace gets too hot, the limit switch tells the blower fan to turn on. This circulates warm air, instead of cold air. It’s important for comfort in cold weather. Also, not all limit switches fit all furnaces. Check compatibility when buying a new part. For those without HVAC expertise, professional installation is recommended.

Pro Tip: Regular maintenance and filter changes can stop overheating and make your furnace parts last longer. Set reminders every few months to keep up with necessary tasks.

About the author

Debarghya Roy: A heating systems author, Passionate about energy efficiency and sustainability, Sharing insights and empowering readers through informative blog articles.