Guide to Furnace Installation

An HVAC technician looking at the inside of an HVAC to determine if there is an issue.

A well-maintained furnace can last 15 to 20 years, so most homeowners must have a new one installed at least once. Understanding the furnace installation process is important.

According to the National Institute of Standards and Technology, improper furnace installation could increase energy usage by as much as 30% compared to a proper installation.

This guide will cover everything you must know about furnace installation, its cost, and the factors to consider as you navigate through the process. 

Table of Contents

Furnace Installation Cost Considerations

The average homeowner pays $4,670 for furnace installation, but the costs can range from $2,800 to $6,780. The cost varies based on many factors, including:

  • Furnace size: The size of the furnace directly affects its cost. The larger the furnace, the more it costs. A good rule of thumb is multiplying your home’s square footage by 40 to get the required BTUs (furnace size).

Using a too-large furnace wastes money and fuel, but it won’t heat your area adequately if it’s too small. The average furnace for a home of 1,300 – 3,000 square feet costs an average of $2,600 – $4,200.

  • Furnace type: Most homes today have natural gas furnaces, but there are other options, including electric, propane, and oil furnaces. The average natural gas furnace costs $3,800 – $10,000, and an electric furnace costs an average of $2,000 – $7,000.
  • Energy efficiency: It’s probably not surprising that a more energy-efficient furnace is more expensive. A furnace’s energy efficiency is measured by its AFUE—annual fuel utilization efficiency. It measures how much fuel is turned into usable energy. The only furnaces that reach 100% are electric furnaces, and the Department of Energy requires only a minimum AFUE of 80% for gas furnaces. High-energy efficiency models have a much higher rating and can cost 50%+ more.
  • Brand: Like any purchase, there are price differences in different brands. In addition, each brand usually has different models with different price points. Some of the most popular furnace brands are Trane, Lennox, Carrier, and Goodman.
  • Humidifier: If your house gets dry in the winter, adding a humidifier during furnace installation may help moisten the air and make everyone more comfortable. This eliminates the need for single humidifiers in each room but increases the furnace cost by $200 – $1,600.
  • Miscellaneous costs: Other costs that affect the total price of a furnace include installation costs, whether the old furnace needs to be removed, and whether a building permit is needed to install a new one.

Professional vs DIY Furnace Installation

Like any home improvement, you have the option of DIY or professional installation. However, installing a furnace is usually best left to the professionals. Improper connections could lead to fires or carbon monoxide leaks, which could be deadly.

Many states require HVAC contractors to be licensed because installing a new furnace can be really dangerous. Professionals have the education, knowledge, and tools to properly and safely install one.

While installing a furnace yourself has some benefits, such as saving on labor costs and working on your own schedule, the downsides quickly outweigh them. Not only are there safety concerns, but you may void the warranty, make mistakes, or may neglect code compliance issues you aren’t aware of.

We recommend hiring a professional for furnace installation using our process below.

Assess Your Needs

Before shopping for a furnace, consider your needs, including the following:

  • Home size: The size of your home determines the right size furnace. A furnace that’s too large or too small will not efficiently heat your home, and you could potentially waste money if it is not the best size for your home.
  • Climate: Determine how often you will use your furnace based on the area’s climate. If you live in an extremely cold climate, you’ll need a furnace that can handle the temperatures, but if you live in an area where temperatures are milder, your heating needs are less extreme, and you may have more options for economical furnaces.
  • Type: Consider the type of furnace that’s best for your home. Some options include packaged systems, split systems, and ductless mini-splits. You must also choose between gas, oil, and electric furnaces. Gas furnaces are the most common, but you have options.
  • Efficiency: If you’re concerned about energy efficiency, look for the ENERGY STAR label or talk to your HVAC professional about energy-efficient options. Keep in mind that the more energy efficient a furnace is, the more it may cost, so compare this to your budget when deciding.
  • Budget: Your budget is a major component of your furnace choice. There are many furnace options at each price point. Be honest about what you can afford for the furnace, installation, and ongoing maintenance. Also, keep in mind the energy costs of running the furnace.

 Furnace Installation Prep

Before electric or gas furnace installation day, prep your home so installation is simple.

  • Schedule an assessment: Even if you know your home’s heating needs, consider an assessment from an HVAC contractor. They will assess your home’s size, the area’s climate, and your personal heating needs to recommend a specific type or size furnace. Consider getting several quotes so you have options to compare.
  • Clean ducts: If, upon your assessment, the professional recommends duct cleaning, have this completed first. Not only must the ducts properly fit the new furnace, but they must be clean to allow your new furnace to work effectively.
  • Prep your home: Make sure HVAC professionals have adequate space to bring in and install the new furnace. Clear all clutter in their path to carry it in and ensure the area surrounding the furnace is free from clutter. They will need ample room to lay out tools and work, so you may need to temporarily move furniture or other large objects.
  • Permits: If your city or county requires a permit for furnace installation, be sure to apply for it early. Without one, the installation process could be delayed.

What to Expect During the Installation

On average, furnace installation takes 12 hours or an entire day. Some factors may increase the timeline, such as:

  • Installing new ductwork
  • Adding a humidifier
  • Installing a new thermostat

After considering any outlying factors, here are the basics of furnace installation and what to expect.

Removal of Old Unit

The time it takes to remove the old furnace depends on several factors, including whether it can be removed in one piece or several. How easy it is to remove a furnace from your house depends on your entryways and how easy you make it for the professionals to remove it from the house.

During furnace removal, the contractors will inspect all furnace connections, including air ducts, water, and oil pipes, to ensure everything is in good enough condition to install a new furnace. Since each furnace is different, you may need additional connections or new ductwork, which can increase the time it takes to remove/install a furnace.

Ductwork Alignment

The ductwork layout is a critical factor when installing new furnaces. Professional contractors will ensure your ductwork is efficient and looks clean throughout the area. If the current ductwork isn’t compatible with the new furnace, the time to install the furnace will increase so they can map out and install a new duct system.

If you don’t need new ducts, the contractor must ensure all connections are sealed tight to ensure optimal efficiency. Any leaks or poor connections could cause energy loss and unnecessarily stress your new furnace.

New Unit Installation

Furnaces typically come in many pieces, which the contractor puts together on-site. Each manufacturer packages furnaces differently, so how long this takes depends on the brand and type of furnace purchased.

If possible, contractors will carry the entire unit to the area where it will be installed and put it together there. If the entryway isn’t large enough, they may do this in parts, which will lengthen the time it takes for installation.

Typically, an HVAC contractor can handle the entire installation, but in cases of major electrical needs, you may need to hire an electrician. This may happen if the new furnace has much greater electrical needs than the existing furnace or if there are fuse issues.

Post-Installation Considerations

After the furnace is installed, contractors must ensure everything is working properly. You must also understand how to maintain the system properly and ask any questions after installation.

Testing Your Furnace

The testing process is the most important part of post-installation. First, the technician must ensure the furnace starts safely and runs properly. They’ll evaluate the temperatures the furnace can accommodate, test the airflow, and ensure all safety measures are in place.

During the testing process, they may run a full cycle, checking each room to ensure it reaches the desired temperature and making any necessary adjustments.

Maintenance Tips

After installing a new furnace, it’s imperative to understand the post-maintenance requirements.

  • Check for debris: After installation, ensure no debris or other items block the furnace, as that could be a fire hazard or restrict proper airflow.
  • Check for loose fittings: Ensure the HVAC contractor checks all fittings to ensure no loose fittings could cause energy loss.
  • Change air filters as suggested: Read the manufacturer’s suggestions for proper air filter usage and how often you should change them. The filter type and brand will determine how often you should change them, but the average filter should be changed every 30 days.

Schedule regular inspections: Set up annual inspections with your HVAC professional to ensure optimal performance. This allows the professional to catch any issues early before they become too damaging and ensures a comfortable temperature in your home.

Addressing Concerns or Questions with Pros

After furnace installation, your HVAC professional can answer any questions or concerns about your new furnace. Common questions include things like:

  • What filters should I use?
  • How often should I change the filters?
  • What’s the optimal temperature to run my furnace?
  • How do I know when there is a problem?
  • Does my furnace have auxiliary heat?
  • How do I turn on the emergency heat if needed?

Choosing the Right Furnace

Choosing the right furnace is a critical part of furnace installation. Here’s what to consider.

Furnace Type

A big part of furnace installation is choosing the right one. There are three primary types of furnaces:

Gas: The gas furnace is the most common option in homes today. It uses the ductwork system and the local gas line to force warm air through the house. The gas jets ignite and create a hot gas that increases the air’s temperature. The air is pushed through the house by a fan that circulates it.

Electric: If you don’t have a natural gas line running to the house, an electric furnace may be an option. Instead of gas, it uses electricity to push warm air through the house. Electric furnaces don’t cost as much as gas furnaces but are also less efficient.

Oil: Oil furnaces are used mostly in the Northeast in areas where gas lines aren’t available, but the weather gets cold. They turn oil into heat. Like electric furnaces, they aren’t as efficient, but they can be an option when gas furnaces aren’t available.

Compare Brands and Features

After deciding on the type of furnace you need, consider the brands, the features they offer, and how they fit your budget. We suggest comparing at least three furnace options to determine which better fits your house and budget.

When selecting the best furnace, consider its compatibility with the following:

Ductwork: Your existing ductwork may be a good fit for the new furnace or need to be changed/repaired. Consider the extra labor costs and work required should you need new ductwork and see how it compares to different furnace options.

Vent types: Ensure the vents in your home are compatible with the furnace type. Each type of furnace creates heat differently and requires different vent materials to ensure your home’s safety.

Chimney: If you have a chimney, ensure it’s clean and adequate to handle the type of furnace you plan to install. Your HVAC contractor can help you determine if it’s a good fit.


Getting a new furnace is a great way to ensure your family’s comfort in the colder months. While saving money on labor costs may be tempting, hiring a professional for furnace installation is best. A professional has the knowledge and education to properly handle all safety precautions and to ensure energy efficiency in your home.

If you’re considering installing a new furnace in your home, call a local HVAC professional today to ensure your family’s safety.


Can I install a furnace myself?

You can install a furnace yourself, but it’s not the safest option. Because furnaces can pose risks, it’s best to pay for professional installation. This provides peace of mind, knowing the installation was done properly and all safety precautions were followed to ensure your home’s safety.

How many hours does it take to install a furnace?

On average, installing a furnace takes 12 hours, but certain circumstances could make it take 2 – 3 days. It depends on the complexity of removing the existing furnace and installing the new furnace. For example, if you need new ductwork or an electrician must handle the electrical portion of the installation, it can lengthen the process.

Is it hard to install a furnace?

Furnace installation isn’t hard for professionals, but as a DIY job, it can be challenging. Unless you have the proper education and understand all necessary precautions to prevent safety issues, leaving it to the professionals is best.

How much does it cost to install a furnace?

On average, it costs $4,670 to install a furnace, but it can cost much less or more, depending on the installation’s brand, size, and complexity.

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