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What’s an HVAC Blower Motor & Why Is It Important?

HVAC blower motors help keep you comfortable year-round. In this article, we explore how blower motors work and how they can affect comfort and efficiency.

What’s an HVAC Blower Motor & Why Is It Important?

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Fire & Ice Team


June 14th, 2022

When shopping for a new furnace, it can be easy to only think about how different furnaces can heat your home. But what if we told you that one component in your furnace could affect your comfort year-round?

This component is known as a blower motor. And as you begin to weigh your furnace options, it’s important to understand how this small component can affect or even upgrade your comfort and your system’s efficiency. 

At Fire & Ice, we’ve helped thousands of homeowners customize their HVAC systems to better meet their needs. And blower motors can be one of the most cost-effective ways to upgrade your system.

In this article, we’ll cover the following topics:

  1. What’s an HVAC Blower Motor?

  2. How Can an HVAC Blower Motor Improve Comfort & Efficiency?

  3. Types of HVAC Blower Motors

  4. Blower Motors & Air Conditioners 

  5. HVAC Blower Motor Maintenance 

  6. Getting the Most Out of Your HVAC System

What’s an HVAC Blower Motor?

The short answer: Your HVAC system’s blower motor helps move conditioned air from your furnace, air conditioner, or heat pump throughout your home year-round. 

Your system’s blower motor is an electric motor housed in your furnace. The blower motor powers your system’s blower fan, also located in the furnace. 

You may already be familiar with your blower fan. Many systems include controls for your blower fan on your thermostat. These are typically referred to by either a fan icon or the word “fan.” 

Typically, thermostats allow you to set your blower fan to run automatically when your system does or to run continuously.

As your HVAC system heats or cools the air, the blower motor and fan force the conditioned air into your home’s ductwork. The ductwork then delivers the conditioned air into individual rooms via registers.

HVAC Systems Before Blower Motors

Many HVAC systems nowadays have blower motors. You also may hear these systems referred to as forced-air systems because blower motors force air throughout your ductwork and, ultimately, your home. 

But forced-air systems have only been available residentially since the 1930s. So before we dive into the modern conveniences of blower motors, let’s briefly look at a precursor to the modern furnace: the gravity furnace.

According to the International Association of Certified Home Inspectors, gravity furnaces were installed between the late 1800s to the mid-1900s. However, some older homes may still have this antiquated furnace. 

Gravity furnaces got their name because they rely on gravity to distribute heated air throughout a home. Unlike the modern furnace, gravity furnaces had no way to force air throughout a home. Instead, they relied on a fundamental principle: warm air rises.

The gravity furnace would burn its fuel source—coal, oil, natural gas, or propane—like a modern forced-air furnace. As the air was heated, it would rise into the ductwork, from which it would travel into individual areas of the home.

This was an incredibly inefficient heating method. By some estimates, only around 50 percent of the heat generated by the gravity furnace went to heating a home. The remaining heat was vented through the chimney with waste gases.

In comparison, modern standard-efficiency furnaces are typically at least 80 percent efficient. And the most efficient furnaces can reach nearly 98 percent efficiency. 

RELATED: How Efficient Is My Furnace? A Full Analysis  

Blower motors aren’t the sole reason modern furnaces are significantly more efficient. In the last century, HVAC manufacturers and the U.S. Department of Energy (DOE) have focused on increasing efficiency for various furnace components. However, blower motors can improve a furnace’s efficiency and your comfort

How Can an HVAC Blower Motor Improve Comfort & Efficiency?

Your system’s blower motor is one of the only HVAC components that runs year-round. Whether it’s hot or cold outside, your system’s blower motor keeps moving conditioned air throughout your home. But a blower motor can help with more than just moving conditioned air throughout your home

A few additional ways your blower motor and fan help keep you comfortable include:

  • Even temperature distribution – Unlike antiquated furnaces, your system can evenly heat and cool your home. Other components also affect how your furnace heats your home or how your air conditioner cools your home. But your blower motor and fan help evenly distribute conditioned air throughout your home. This can help keep temperatures throughout your home more consistent.

  • Improved air circulation – While your blower motor and fan run, they increase circulation throughout your home. This also helps keep temperatures consistent throughout your home. 

  • Improved air quality – As your blower motor and fan help circulate air throughout your home, the air passes through your HVAC filter. The more often your blower fan runs, the more dust and debris are filtered from the air in your home. Some filters can also help remove allergens and odors.

We always recommend that our customers run their blower motors as often as possible. When you set your blower fan to “on” instead of “auto” on your thermostat, it can do its job even when your furnace or air conditioner isn’t running. This means that you get the benefits of even temperature distribution, improved air circulation, and improved air quality more often throughout the day.

In some cases, running your blower motor and fan more frequently can also help save you money on energy costs. When you maintain consistent temperatures throughout your home, your furnace or air conditioner typically doesn’t need to run as frequently to reach your preferred temperature.

However, this can depend on other factors, including the size of your HVAC equipment and humidity levels inside your home. If you notice spikes in energy costs or uneven temperatures, your HVAC service provider should be able to help identify the issue.

Types of HVAC Blower Motors

Although all blower motors have the same primary function, there are multiple types, some of which have notable features.

Depending on when your furnace was manufactured, you may have one of three types of blower motors:

  • Permanent Split-Capacitor (PSC)

  • Electronically Commutated Motor (ECM)

  • Variable-speed

We’ll break down the features and benefits of each in the sections below.

A Note on Gas Valves

Before we break down each type of blower motor, it’s important to understand a few additional terms.

When it comes to furnaces, two sets of terminology are easy to confuse: the terms used for blower motor speed and the terms used for gas valve staging.

Blower motor speed often refers to the number of speed settings a blower motor can run at. Some types of blower motors have multiple speed settings. This can mean that your system’s fan may run at full speed, low speed, or anywhere in between. 

Gas valve staging refers to how much fuel your furnace uses to heat your home at a time. Like blower motor speed, some furnaces can adjust their fuel output and heating capacity to precisely maintain a set temperature.

For blower motor speeds, there are typically three options:

  • Single-speed – Either on or off

  • Two-speed – Typically either on, off, or a lower-capacity speed

  • Variable-speed – Multiple settings between 0% and 100% full speed

We’ll discuss the pros and cons of each option in the sections below.

For gas valve staging, furnaces typically have one of the below types of gas valves:

  • Single-stage – Either on or off. This is a straightforward heating process, but single-stage furnaces can struggle to heat upper floors in some cases

  • Two-stage – Typically either on, off, or at a lower capacity. This typically reduces how much fuel a furnace uses at once, especially on milder days

  • Modulating – Multiple capacities between 0% and 100% full capacity. This allows a furnace to constantly adjust its fuel intake, maintaining a set temperature without using unnecessary fuel

Both sets of terms are frequently used during in-home estimates, so you may hear combinations of the above. 

Later in this article, we’ll touch on how your blower motor works with your gas valve and air conditioner. However, if you’d like to learn more about staging, check out this article that breaks down the three staging options.

PSC Blower Motors 

Permanent split-capacitor (PSC) blower motors were created with two settings: on or off. This is also an example of a single-speed blower motor.

PSC blower motors are also the least efficient type of blower motor on this list. Although a PSC motor also helps distribute air throughout your home, it requires more energy.

And unlike ECM and variable-speed blower motors, PSC motors kick on at full force. This creates more wear and tear on the PSC motor over time. This is also why PSC motors are typically louder than ECM or variable-speed blower motors.

As of 2019, HVAC manufacturers can no longer produce furnaces with PSC blower motors due to DOE regulations. However, HVAC contractors can still sell furnaces with PSC blower motors as long as the furnace meets installation guidelines

If your furnace was installed before or around July 3, 2019, it could have a PSC motor. To confirm whether it does, refer to your owner’s manual or speak with your HVAC contractor.

ECM Blower Motors

Electronically Commutated Motors (ECM) were designed to run more efficiently than PSC blower motors. And since July 2019, the DOE has required HVAC manufacturers to use ECM instead of PSC blower motors as part of an initiative to reduce the energy consumption of HVAC equipment.

Today, ECMs are used as single-speed and two-speed blower motors. However, ECMs allow HVAC contractors to adjust their speed settings to fit your home. 

To be clear, ECMs can’t automatically adjust their settings throughout a 0% to 100% range. But manually adjusting these settings can help optimize ECMs to better meet your needs.

ECMs can be paired with both single-stage and two-stage gas valves. Compared to PSC blower motors, ECMs can improve comfort and efficiency. ECMs are also typically much quieter than PSC motors.

With optimized speed settings, ECMs can switch to the appropriate speed setting based on your furnace’s heating output. And if you continuously run your HVAC system’s fan, an ECM can help circulate the air without creating as much of a draft when your furnace isn’t heating your home.

Despite the ruling from the DOE, ECM technology was available before 2019. To determine whether your system has an ECM motor, refer to your furnace’s owner’s manual or ask your HVAC contractor.

Variable-Speed Blower Motors

Variable-speed blower motors are the most efficient type of blower motor. Unlike ECM and PCS blower motors, variable-speed blower motors can automatically adjust their speed. 

Variable-speed blower motors can adjust their speed from 0% to 100%. As a result, they tend to run longer than other types of blower motors.

With this longer runtime, you can also get the benefits we mentioned earlier: more even temperature distribution, improved air circulation, and improved air quality.

We typically recommend furnaces with variable-speed blower motors to homeowners who have comfort concerns. This typically means they’re looking to solve a problem when replacing their existing furnace.

Comfort concerns can include:

  • Hot and/or cold spots in specific rooms, areas, or floors

  • Allergies and viruses

  • Stuffy, hot rooms during summer

  • Dry air during winter

  • System noise

RELATED: Understanding Your Comfort Concerns

Furnaces with variable-speed blower motors are typically more expensive than furnaces with ECMs. However, variable-speed blower motors typically only increase the cost of a new furnace by approximately $100. This can make variable-speed blower motors a cost-effective upgrade.

For information, check out this article that breaks down the pros and cons of variable-speed blower motors.

Blower Motors & Air Conditioners 

Now that you know more about the different types of blower motors, let’s discuss how your blower motor determines your cooling options.

As we mentioned, blower motors help distribute conditioned air throughout your home year-round. Your blower motor must be compatible with your air conditioner to ensure your air conditioner can properly cool your home.

Like gas valves, air conditioners also have stages. Air conditioners can be one of three options:

  • Single-stage

  • Two-stage

  • Variable-speed

In general, an air conditioner’s staging should at least match your blower motor’s speed settings. Otherwise, your air conditioner may not be able to perform properly.

So if you have a variable-speed air conditioner, you’ll need a variable-speed blower motor. If you have a two-stage air conditioner, you’ll need a two-speed or variable-speed blower motor. If you have a single-stage air conditioner, you can have any blower motor—single-speed, two-speed or variable-speed.

As long as your blower motor meets the minimum speed requirements, your air conditioner will be able to cool your home as the manufacturer intended. And if you’re looking for added comfort, you can always upgrade your blower motor.

HVAC Blower Motor Maintenance 

As with any mechanical component, blower motors can require maintenance. However, blower motor maintenance is typically combined with routine furnace maintenance. 

We typically recommend one furnace tune-up each year. During an annual furnace tune-up, your HVAC service provider should check your system’s blower motor and fan to ensure it’s running properly.

Your system’s blower fan may also occasionally need to be cleaned. Over time, dust and debris can cover your system’s blower fan. As more and more dust gathers on the fan, you may notice changes in temperatures or air quality.

Some HVAC maintenance plans cover equipment cleaning. Otherwise, you may be charged an extra fee to clean your system’s blower motor.

You can also help maintain your system’s blower motor by changing your furnace filter as recommended. 

Getting the Most Out of Your HVAC System

Although blower motors aren’t the most glamorous component, they can pack a punch when it comes to upgrading your comfort.

Whether you’re replacing a furnace or your full system, it’s important to match your HVAC equipment to your needs.

If you’re in the market for a new furnace, we’d love to understand your comfort concerns and help customize your HVAC system to meet your needs.

Use the zip code lookup below to take the first step toward your new HVAC system.

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