How to Replace a Gas Furnace: A Step-by-Step Guide

If your gas furnace is old or not working efficiently, it may be time to replace it. A new gas furnace can save you money on your energy bills and provide better heating for your home. However, replacing a gas furnace can seem like a daunting task, especially if you’ve never done it before. In this article, we’ll provide a step-by-step guide on how to replace a gas furnace, so you can do it yourself or know what to expect if you hire a professional.

Steps to Prepare for Gas Furnace Replacement

Before you start replacing your gas furnace, there are a few steps you need to take to prepare.

Step 1: Turn off the gas supply

The first thing you need to do is turn off the gas supply to your furnace. Locate the gas valve and turn it off. If you’re not sure where the gas valve is, consult your furnace manual or contact a professional for assistance.

Step 2: Disconnect the power supply

Next, you’ll need to disconnect the power supply to your furnace. Turn off the power switch on your furnace or flip the circuit breaker that powers your furnace. This will prevent any accidents from happening while you’re working on the furnace.

Step 3: Remove the old furnace

Once you’ve turned off the gas and power supply, you can start removing the old furnace. This may involve disconnecting the gas line, electrical connections, and air ducts. Follow the manufacturer’s instructions or consult a professional if you’re not sure how to do this.

Step 4: Choose a new furnace

After you’ve removed the old furnace, you’ll need to choose a new one. Consider the size of your home, your heating needs, and your budget when selecting a new furnace. You may want to consult a professional to help you choose the right furnace for your home.

Installation of the New Gas Furnace

Once you have your new furnace, it’s time to install it. Here’s how to do it:

Step 1: Connect the gas line

Connect the gas line to your new furnace according to the manufacturer’s instructions. Make sure the gas valve is turned off before you do this.

Step 2: Connect the air ducts

Connect the air ducts to your new furnace. This will involve attaching the ductwork to the furnace and connecting it to the vents in your home.

Stay Tuned for next two sections.

Installation of the New Gas Furnace (Continued)

Step 3: Connect the power supply

Connect the power supply to your new furnace. This may involve connecting electrical wires or plugging in the furnace to an electrical outlet. Follow the manufacturer’s instructions and make sure the power is turned off before you begin.

Step 4: Test the new furnace

Before you start using your new furnace, you’ll need to test it to make sure it’s working correctly. Turn on the gas and power supply, then turn on the furnace. Wait for it to start heating up and check the air vents to make sure warm air is coming out. If everything is working correctly, you’re ready to start using your new furnace!

Additional Considerations

There are a few additional things to consider when replacing a gas furnace:

Hire a professional or do it yourself?

While it’s possible to replace a gas furnace yourself, it’s a complicated and potentially dangerous task. If you’re not confident in your abilities or don’t have the necessary tools, it’s best to hire a professional. A professional will ensure that your furnace is installed correctly and safely.

Permits and regulations

In some areas, you may need a permit to replace your gas furnace. Check with your local building department to see if you need a permit and to ensure that you’re following all local regulations.

Energy efficiency ratings

When choosing a new furnace, consider its energy efficiency rating. A more energy-efficient furnace will save you money on your energy bills in the long run. Look for furnaces with high AFUE (annual fuel utilization efficiency) ratings, which indicate how much of the fuel used by the furnace is converted into heat.

By following these steps and considering these additional factors, you can replace your gas furnace safely and efficiently, ensuring that your home stays warm all winter long.


Replacing a gas furnace can seem overwhelming, but with the right preparation and knowledge, it’s a manageable task. By turning off the gas and power supply, removing the old furnace, choosing a new one, and installing it correctly, you’ll have a new furnace up and running in no time. It’s also important to consider hiring a professional, obtaining any necessary permits, and choosing an energy-efficient furnace to save you money in the long run. At Gogo Gidget, we hope this guide has been helpful in your gas furnace replacement journey.

Maintenance of the New Gas Furnace

After you’ve installed your new gas furnace, it’s important to maintain it properly to ensure it lasts as long as possible and operates efficiently. Here are some tips for maintaining your new furnace:

Change the air filter regularly

One of the most important things you can do to maintain your furnace is to change the air filter regularly. A dirty air filter can cause your furnace to work harder than it needs to, reducing its efficiency and potentially causing damage. Check your furnace manual for instructions on how often to change the air filter, or consult a professional.

Schedule annual professional maintenance

Even if you change the air filter regularly, it’s still a good idea to have a professional inspect and maintain your furnace annually. A professional can check for any potential issues and make sure your furnace is running at peak efficiency. They can also perform any necessary maintenance, such as cleaning the furnace and lubricating moving parts.

Troubleshooting common issues

If you notice that your furnace isn’t working as it should, there are a few common issues you can troubleshoot before calling a professional. For example, if your furnace isn’t producing heat, check the thermostat to make sure it’s set to the correct temperature and the batteries are working. If your furnace is making strange noises, it could be a sign of a mechanical issue.


Replacing a gas furnace can seem like a daunting task, but with the right preparation and knowledge, it’s something you can do yourself or with the help of a professional. In this article, we’ve provided a step-by-step guide on how to replace a gas furnace, from preparing for the replacement to installing the new furnace. We also discussed the importance of maintaining your new furnace to ensure it lasts as long as possible and operates efficiently. Remember, regular maintenance is key to getting the most out of your new furnace. By following these tips, you can enjoy a warm, comfortable home all winter long.

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