How Long Does it Take to Install a Furnace?

Getting ready to replace your old furnace or need to install one in your new home?

It can take anywhere between 4 to 10 hours to install a new furnace. Depending on how large the furnace is and the size of your home will affect how fast your furnace will be installed.

Below you’ll also find out what to expect from the installation process, which type of furnace is best, and what to expect from the installation process.

Let’s get started.

How Long Does it Take to Install a Furnace?

If you have pre-existing ductwork inside of your home that doesn’t need repairs or replacing, your furnace should be installed anywhere between 4 to 10 hours.

The time it takes will depend on your installer’s efficiency and the size of your furnace.

Larger, more complex furnaces will take longer to install. Smaller furnaces will not take as much time to install as the installation is not as difficult.

Factors that can Cause Longer Furnace Installation Time

Size of home

The size of your home will determine how large of a furnace you’re going to require.

Larger furnaces are more complex to install and may require more ductwork to be installed.

Unknown issues

If you’re replacing a furnace, you’ll not only have to remove it but deal with any issues that may arise after the fact.

If your HVAC technician finds issues with your ductwork, gas lines, or electrical, then you’ll need to factor that into your installation time.

While not super common, you may realize your plumbing is leaking near your furnace which is another cause for concern.

Speed of your installer

Not all HVAC technicians are equal and neither are their installation times. Your technician may be speedy or maybe an old-timer that likes to take their time.

This isn’t in your control, but it’s best to double check on your repair man to ensure that they’re getting the job done.

Which Type of Furnace is Right For You?

Before you decide on a furnace that’s right for you, consider the two main options, electrical and combustion. Both have their pros and their cons.


Electrical furnaces are more efficient than traditional combustion furnaces.

They generate heat from coils that are then distributed through your home’s ductwork with a fan.

An electrical furnace is easier to install than a gas furnace as you won’t need to hook up any natural gas lines.

They’re easy to maintain and replace, and they’re rated to last 20 to 30 years which is almost twice as long as a combustion furnace.

While an electrical furnace is an economical choice up front, over the long run, you’ll have to pay more for electrical costs.

Electrical furnaces also take longer to heat your home than gas furnaces.


Gas furnaces are faster at heating your home, which can be important during emergencies. They’re also more efficient than electrical furnaces to run.

You’ll find many air conditioners without heat pumps offer gas furnaces alongside the main HVAC unit.

While it may seem counterintuitive, natural gas is far better for the environment than electricity.

Modern furnaces are far more energy-efficient than they used to be, and you can check the annual fuel utilization efficiency (or AFUE) to see how efficient your furnace will be.

On the downside, gas furnaces can cost much more to install. The biggest risk you’ll encounter with a gas furnace is carbon monoxide.

Improper installation or a faulty furnace can lead to carbon monoxide leaks which can be fatal.

Gas furnaces also last only 15 to 20 years while an electric furnace lasts around 20 to 30 years. Oil furnaces last around 25 years.

Factoring in all of these considerations, it’s going to be a personal preference as to which furnace is right for you. If you’d like to save on energy costs, then go with the gas furnace.

If you want the safety of an electric furnace, then go with electric.

Can I install a Furnace Myself?

You can install a furnace yourself. You will have to remove the old furnace and install the new furnace in its place.

Consider that your local municipality requires a permit to do so.

You may also need to hook up a gas line or install new ductwork for your furnace.

All of these factors can make for a complex installation, so it may be better to look into hiring a local professional to aid in the furnace installation process.

What is the Furnace Installation Process Like?

Step 1. Choose the furnace

Before you purchase a new furnace, you’re going to want to know what size furnace is right for your home.

Too small and you won’t be able to heat your entire home, too large and it’ll be noisy and inefficient.

An average two bedroom, 2000 square foot home will need around 80,000 to 115,000 BTUs to heat your home properly.

Step 2. Remove your old furnace

Before your new furnace can be put in, you’ll need to remove your old one.

Ensure that all the power is off before you remove any electric wires. The gas should be turned off as well before removing your furnace.

Step 3. Check the drain and ducts

Your HVAC technician will do a lot of checks before going ahead with the installation process.

This is to ensure that you won’t have any issues moving forward as a furnace can be dangerous if installed incorrectly.

The existing drains and ductwork should be suitable, but you may encounter issues where you need to install new ducting.

If this is the case, your technician will advise you on the best course of action to get your furnace installed.

Step 4. Connect the gas and vent pipes

After the new furnace has been installed, you’ll need to connect the vent pipes as well as the gas supply.

The vent pipe removes toxic gases that occur during the combustion process is used to heat your home.

If you don’t have a gas line, you’ll need to install a new one. It’s a good time to check for any gas leaks to ensure that there isn’t a leak around the furnace.

Step 5. Connect the electrical

Your furnace will need to be wired to your electrical system as well as the thermostat.

If you are doing it yourself but aren’t confident enough to work with electricity, then you should call a professional to come to give you a hand.

Step 6. Double-check everything is working

After everything has been installed, it’s time to test if your furnace is working properly.

Another round of gas and carbon monoxide checks should take place to ensure there are no leaks nearby.

Should I Call an HVAC Technician?

If you aren’t sure what type of furnace you’re going to need or want to ask a few questions regarding your new furnace installation, feel free to reach out your local HVAC professionals. They’re ready at any moment to give you a free quote.

Final Thoughts

While it can seem like a long process, 4 to 10 hours is about how long to expect a furnace to be installed.

You may encounter issues where you need to install additional ductwork or find out you have a gas or carbon monoxide leak.

In these instances, you will need to lengthen the installation time.

It’s best to have a professional technician aid you in the furnace installation process if you aren’t sure how to do it yourself.

The electrical, gas, and venting work should be done professionally as a furnace can be dangerous if installed incorrectly.

About Roy Cohen

Roy Cohen has a burning passion for heating, cooling, and ventilation. He aims to help you save money on expensive repairs and bring you the best HVAC products. He has years of experience behind him in HVAC repair and garage maintenance.

You can find Roy at his LinkedIn or his email: [email protected]

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