When making HVAC decisions for your home, it pays to do your research and be an informed consumer. For example, you can choose between a single-stage and a two-stage furnace for your heating needs. Both types offer unique benefits and operate differently to provide comfort.

This guide breaks down the functionality, features, advantages and considerations of single-stage and two-stage furnaces to help you determine which option you prefer.

What Is a Single-Stage Furnace?

A single-stage furnace operates at a fixed, high capacity, turning on and off as needed to maintain the desired temperature. The system either runs at maximum power or not at all, with no middle ground. Once it reaches your set temperature, the furnace shuts off, cycling back on as necessary throughout the day.

This straightforward solution is typically more affordable to purchase and install. Known for their reliability, single-stage furnaces have fewer components that can fail, resulting in a lower likelihood of mechanical issues and breakdowns. With a single heat output level, these furnaces quickly warm your home, which your family will appreciate in frigid weather.

Though single-stage furnaces are convenient, their constant on/off cycling makes them less energy efficient. This lack of modulation can also result in temperature fluctuations, leaving your family wanting additional flexibility to meet your varying heating needs.

How Does a Two-Stage Furnace Work?

In contrast, a two-stage furnace has two output levels – high for colder days and low for milder days. The two-stage operation is adjustable and demand-based, allowing for more precise temperature control and improved efficiency. This balanced approach enhances comfort and minimizes equipment wear and tear, while increasing energy savings.

The low stage typically operates at approximately 60% to 70% of the furnace’s full capacity, which is ideal on milder days. The high stage kicks in when the temperature drops and you need maximum heat.

The ability to modulate heat output without continual on/off cycling maintains a more consistent indoor temperature, reducing the fluctuations that characterize single-stage systems. Running at a lower capacity for longer periods also improves air circulation and filtration for an even distribution of warmth, without overworking the furnace.

Key Differences Between Single-Stage and Two-Stage Furnaces

If it’s time to replace your furnace, you must understand the features that can impact your comfort, utility bills and satisfaction with your investment.

Operation Modes

  • Single-stage furnaces operate at one fixed capacity, running at full power and shutting off when it reaches the temperature you set on your thermostat.
  • Two-stage furnaces adjust their output based on heating demand, primarily operating on the low stage for most of the time and switching to high only when necessary.

Energy Efficiency

  • Single-stage furnaces are typically less energy efficient because they repeat the on/off cycle multiple times a day.
  • Two-stage furnaces reduce utility bills and provide more consistent heating, resulting in fewer hot and cold spots throughout your home.

Noise Levels

  • Single-stage furnaces can be noisier because they run at 100% capacity every time they turn on.
  • Two-stage furnaces provide a quieter operation in the lower-power mode.

Cost and Installation

  • Single-stage furnaces are generally a more affordable choice, with lower upfront price tags and installation costs. However, the repeated on/off cycling can lead to additional strain on the system, potentially necessitating frequent furnace repair and service calls as the system ages.
  • Two-stage furnaces have a higher initial cost due to their more complex design. However, the long-term energy savings will offset the initial investment with time. They also tend to have longer lifespans due to their efficient operation.

Energy Efficiency: Which Furnace Saves More?

Running your furnace all winter can lead to substantially higher utility bills and a larger carbon footprint. A two-stage furnace uses less energy than a single-stage furnace by primarily operating in the low stage. This reduced consumption translates to cost savings that will add up over the years and contribute to a more sustainable, environmentally friendly home.

Though a two-stage furnace costs more upfront, the long-term savings, furnace efficiency and environmental benefits make it a worthwhile investment that will ultimately pay for itself. You will also enjoy more even warmth throughout the colder months.

Comfort Levels: Single-Stage vs. Two-Stage Furnaces

Single-stage furnaces cycle on and off, making it challenging to maintain a consistently comfortable temperature in your home. They provide nearly immediate warmth when operating at 100%. However, a single-stage system will shut off once it reaches your set temperature, which may leave you feeling chilly until the furnace comes on again.

Two-stage furnaces offer more precise temperature control by running at a lower capacity for longer periods. This modulation reduces fluctuations and maintains a more consistent indoor climate.

Cost Considerations: Installation and Maintenance

Here’s some information you’ll need to know when accounting for how furnace installation and maintenance costs will affect your household budget and long-term savings.

Installation

  • Single-stage furnaces have a simpler design with fewer components, making them an attractive choice for homeowners who want to save money.
  • Two-stage furnaces usually cost more to purchase and install, but remember that the long-term energy savings may balance this higher upfront investment.

Maintenance

  • Single-stage furnaces offer less complex repair needs, which may reduce the price of repairs if you encounter a problem.
  • Two-stage furnaces require more specialized maintenance due to their advanced technology.

Long-Term Savings

  • Energy efficiency: While a single-stage furnace may have lower initial costs, its higher energy consumption means you will pay more to use it. In contrast, a two-stage furnace can slash your heating bills over its lifetime.
  • System longevity: Routine maintenance is the best way to prolong your HVAC equipment’s lifespan. Two-stage furnaces tend to experience less wear and tear, possibly reducing the frequency and cost of repairs.

Which Furnace Is Best for Different Climates?

Two-stage furnaces are often the best choice to stand up to Omaha’s harsh winters, keeping your home warm and your energy bills manageable despite the frigid temperatures. The ability to modulate heat output lets you maintain a consistent indoor climate, even during extreme cold. The high stage provides maximum heating when you need it, while the low stage efficiently maintains comfort on milder days.

Choosing the Right Furnace for Your Home

A-1 United is Omaha’s leading heating and air conditioning company. Over our decades in service, we have built a reputation as one of the Midwest’s largest Lennox and American Standard dealers. Call us today at 402-593-7500 for prompt, reliable HVAC installation, maintenance and repairs from our knowledgeable technicians. We have won multiple customer service awards and proudly recommend the Lennox Signature® Collection to homeowners who want the pinnacle of home heating.