Single-Stage vs. Two-Stage vs Variable Speed Furnaces: A Comprehensive Guide for Denton County Homeowners

Residences of Sanger, Texas, are no strangers to scorching hot weather. However, they also see their fair share of cold temperatures. According to weatherspark.com, Sanger generally sees low temperatures of 34° Fahrenheit. Furnace selection isn’t something you should overlook, so in this blog post, Cote’s Mechanical will help you understand the difference between one-stage, two-stage, and variable speed gas furnaces.

Understanding Furnace Types: Single-Stage vs. Two-Stage vs. Variable Speed

Terms like variable speed and two-stage furnaces refer to their blowers. Single-stage furnaces only operate at maximum power. Two-stage furnaces can only operate on two settings—high or low, while variable speed furnaces can operate on multiple.

What is a Single-Stage Furnace

Single-stage, aka single-speed furnaces, is the most basic type of furnace. They run at maximum power whenever they are on. 

What is a Two-Stage Furnace

More advanced than a single-stage furnace is a two-stage, aka, two-speed furnace. Two-stage furnaces, unlike single-stage furnaces, feature a high and low setting. This gives them increased efficiency over single-stage furnaces.

What is a Variable Speed Furnace

Variable speed, aka variable function furnaces, are more advanced and efficient than single- and two-stage furnaces. They can monitor your home’s temperature and make incremental adjustments accordingly. They offer exceptional precision for warming your home.

Key Differences Between Single-Stage, Two-Stage, and Variable Speed Furnaces

While their purpose is the same, variable speed, single-stage, and two-stage furnaces have significant differences, including:

Efficiency and Energy Savings

Single-stage: Single-stage gas furnaces are the least effective form of gas furnaces, as they always run at full power.

Two-Stage: Two-stage furnaces offer a high and low mode, enabling greater efficiency. While not the most efficient furnaces available, they are a step above single-stage furnaces.

Variable-Speed: Variable-speed furnaces have greater efficiency and energy savings than single- and two-stage furnaces.

Comfort and Temperature Consistency

Single-stage: Single-stage furnaces do well heating smaller homes, but they struggle with larger ones. As areas close to warm air vents warm quickly, the one-stage furnace may be “tricked” into turning off early, causing cold spots.

Two-stage: Two-stage furnaces adjust to prevent cold spots from forming better than single-stage furnaces.

Variable Speed: Variable speed furnaces offer greater comfort than one- and two-stage furnaces.

Noise Levels

Single-stage: Single-stage furnaces tend to be the noisiest as they only run at maximum power.

Two-stage: Since two-stage furnaces have a high and low setting, they won’t always run on full power like single-stage furnaces, so they can be quieter.

Variable speed: Variable speed furnaces can function at lower speeds when they aren’t required to be at full capacity, helping to reduce noise. 

Cost and Initial Investment

While certain types of furnaces tend to be more expensive than others, the price can vary from model to model.

Single-stage: Because of their simplicity, single-stage furnaces tend to be the least expensive to buy. However, their lack of efficiency can cause them to be more expensive over time.

Two-stage: The price and operating costs of two-stage furnaces generally fall in the middle of single-stage and variable speed furnaces. While the two-stage tends to cost more than a single-stage, it offers better energy efficiency.

Variable speed: Given its complexity, variable speed furnaces are more expensive to purchase than two-stage furnaces. However, the energy savings of variable speed furnaces means they save more money over time.

Compatibility with HVAC Systems

Depending on the type of furnace you select, it may or may not be compatible with your HVAC system. Please note that depending on the furnace you select, your warranty may be voided.

Pros and Cons of a Single-Stage Furnace

Pros

• Generally lower initial cost.
• Potentially less expensive repairs given its simplicity.

Cons

• Less efficient than other types of furnaces.
• Noisier.
• Ambient temperature variation when heating big or multiple-floor homes.
• May not last as long as other types of furnaces.
• Less effective at removing humidity than two-stage and variable speed furnaces.

Pros and Cons of a Two-Stage Furnace

Pros

• More efficient than a single-stage furnace.
• More comfortable than a single-stage furnace.
• Quieter than a single-stage furnace.
• Better at lowering humidity than a single-stage furnace.

Cons

• Generally higher initial cost than a single-stage furnace.
• Potentially more expensive to repair than a single-stage furnace.

Pros and Cons of a Variable Speed Furnace

Pros

• Excellent efficiency.
• Greater level of comfort than one and two-stage furnaces.
• Greater at lowering humidity than a one and two-stage furnace.

Cons

• Tends to have a higher initial cost than single and two-stage furnaces.
• Complexity makes repairs and installation more difficult.

Which Furnace is Right for Your Home in Denton County?

Factors such as local climate and the size of your home play a role in determining which furnace is right for your home. Since each situation is different, you should consult an HVAC professional on the best furnace for your home.

The following factors affect what furnace is right for your home.

Home Size

For larger homes, we recommend two-stage or variable speed furnaces. Single-stage furnaces may not be able to effectively heat it.

Climate

While Denton County has a warmer climate, it does see freezing temperatures. Because of this, a two-stage, or ideally variable speed, might be the right option for better comfort, depending on your budget. You might appreciate the variable speed furnace’s efficiency at lowering humidity. 

Why Choose Cote’s Mechanical for Your Furnace Installation in Denton County?

Since 2001, Cote’s Mechanical has been helping people with their HVAC needs in Sanger, Texas, and the Denton County area. Our work has earned us many five-star reviews and an A+ rating from the Better Business Bureau. We have years of experience installing single-stage, two-stage, and variable speed gas furnaces. With our knowledge of gas furnaces, we can help you select the right one for your home. For furnace installation, service, or help with other HVAC needs in Denton County, contact the professionals at Cote’s Mechanical.

Frequently Asked Questions About Furnace Types

Additional Resources

• Furnace Spotlight, Trane
• Avoid Dangerous Heater Malfunctions with Maintenance