Two-stage gas furnaces are among the best choices for homeowners who want better comfort and efficiency without paying for a fully modulating furnace. Instead of operating at only one firing rate, a two-stage furnace can typically operate at a lower heating output for milder conditions and switch to its higher stage when the home needs more heat.
This approach can reduce temperature swings, extend heating cycles, improve comfort and, when properly matched to the home, reduce unnecessary full-output operation. Two-stage furnaces are available from major U.S. HVAC manufacturers including Carrier, Lennox, Trane, Rheem and others.
For 2026, our top choices include the Carrier Infinity 96 for premium comfort, the Lennox EL297V for a high-efficiency variable-speed combination, the Lennox EL296V for value, and the Trane S8X2 for homeowners who prefer a simpler two-stage design. Exact model availability and specifications can vary by region and equipment size.
Best Two-Stage Gas Furnaces: Our Top Picks
| Furnace | AFUE | Blower | Heating | Best For |
|---|---|---|---|---|
| Carrier Infinity 96 59TN6 | Up to 96.7% | Variable-speed | Two-stage | Best overall |
| Lennox EL297V | Up to 97% | Variable-speed | Two-stage | High efficiency |
| Lennox EL296V | Up to 96% | Variable-speed | Two-stage | Best value |
| Carrier Performance 96 59TP6 | Up to 96.7% | Variable-speed | Two-stage | Carrier value |
| Trane S8X2 / 80 Two-Stage | Up to 80% | 9-tap blower | Two-stage | Simple, non-condensing system |
| Lennox EL297E | Up to 97% | Constant-torque | Two-stage | High efficiency at lower complexity |
Note: Furnace efficiency and features can differ between individual sizes and configurations. Always verify the exact model number and current certification status before purchasing.
What Is a Two-Stage Gas Furnace?
A two-stage gas furnace has two levels of heating output rather than one.
A conventional single-stage furnace essentially has one firing rate. When the thermostat calls for heat, it generally operates at its designated heating output until the call for heat ends.
A two-stage furnace can operate at a lower first-stage output for many heating calls and use its second, higher stage when additional capacity is needed.
For example, a furnace might operate at a lower output during a cool but not extremely cold day. When outdoor temperatures fall substantially or the home needs heat quickly, the furnace can move into second stage.
The exact staging percentages vary by model, so homeowners should not assume that every two-stage furnace operates at the same low-stage capacity.
How Two-Stage Heating Works
The basic operating sequence is relatively simple:
- The thermostat detects that the indoor temperature is below the target.
- The furnace starts in first stage when conditions allow.
- The furnace supplies heat at its lower firing rate.
- If the heating demand continues or additional capacity is required, the furnace moves to second stage.
- Once the thermostat is satisfied, the heating cycle ends.
Many systems spend a significant amount of their heating time in first stage. Carrier, for example, says its Infinity 96 59TN6 can run in low stage up to 90% of the time under appropriate conditions.
Why Buy a Two-Stage Furnace?
The biggest advantage is not simply the number “two.” The advantage is the ability to provide heating output that is better matched to the home’s current demand.
More consistent temperatures
Running at a lower output for longer periods can reduce the dramatic temperature swings sometimes associated with short, full-output heating cycles.
Improved comfort
Instead of repeatedly delivering large amounts of hot air, a properly configured two-stage system can provide more gradual heating.
Potentially quieter operation
When the furnace operates in its lower stage, airflow and burner operation can be less aggressive than during high-stage operation.
Better efficiency
Two-stage operation can improve overall system performance by allowing the furnace to spend more time operating at lower output. However, two-stage operation does not automatically guarantee a specific percentage of energy savings.
Better humidity control
When combined with a variable-speed blower and compatible cooling equipment, longer operating cycles can improve air mixing and potentially assist with summer humidity management.
Two-Stage vs. Single-Stage Gas Furnaces
| Feature | Single-Stage | Two-Stage |
|---|---|---|
| Heating outputs | One | Two |
| Typical comfort | Good | Better |
| Temperature consistency | Moderate | Generally better |
| Initial equipment cost | Lower | Higher |
| System complexity | Lower | Higher |
| Potential efficiency | Good | Very good |
| Best use | Budget installations | Comfort-focused homes |
Two-Stage vs. Modulating Furnaces
A two-stage furnace should not be confused with a modulating or variable-capacity furnace.
A two-stage furnace has two primary firing levels. A modulating furnace can adjust its heating output across a much wider range.
| Feature | Single-Stage | Two-Stage | Modulating |
|---|---|---|---|
| Output levels | 1 | 2 | Many |
| Comfort | Good | Very good | Excellent |
| Equipment cost | $ | $$ | $$$ |
| Complexity | Low | Moderate | High |
| Efficiency options | Moderate to high | High | Very high |
| Ideal buyer | Budget-focused | Comfort/value-focused | Maximum comfort |
For many homeowners, two-stage heating is the sweet spot. It can provide many of the practical comfort benefits of more advanced systems without the price and complexity of a premium modulating furnace.
1. Carrier Infinity 96 59TN6 — Best Overall Two-Stage Furnace
The Carrier Infinity 96 59TN6 is our top overall choice for homeowners who want a premium two-stage furnace.
Carrier rates the model at up to 96.7% AFUE and lists a two-stage gas valve, variable-speed blower and ENERGY STAR certification. Carrier also says the furnace can operate in low stage for up to 90% of the time under suitable conditions.
Key features
- Two-stage gas heating
- Up to 96.7% AFUE
- Variable-speed blower
- Infinity system compatibility
- Advanced comfort controls
- Natural gas operation with optional propane conversion configuration
The variable-speed blower is particularly important. A two-stage burner paired with a basic blower does not provide the same type of airflow control as a two-stage furnace paired with a variable-speed motor.
Pros
- Excellent comfort
- High efficiency
- Variable-speed airflow
- Strong humidity-management features when properly paired with compatible equipment
- Premium control options
Cons
- Higher equipment cost
- More complex controls
- Best results may require a compatible Carrier control system
- Installation quality is critical
Best for: Homeowners willing to pay more for comfort, quiet operation and advanced system control.
2. Lennox EL297V — Best High-Efficiency Two-Stage Furnace
The Lennox EL297V is one of the most interesting two-stage furnaces in Lennox’s current lineup.
Lennox lists the EL297V as a high-efficiency digital, two-stage, variable-speed gas furnace with efficiency up to 97% AFUE. Lennox also identifies it as ENERGY STAR qualified.
The combination of two-stage heat and variable-speed airflow makes it a particularly strong option for homeowners who want high efficiency without moving all the way to a fully modulating furnace.
Why choose the EL297V?
- Up to 97% AFUE
- Two-stage heating
- Variable-speed blower
- High-efficiency condensing design
- Good comfort potential
- ENERGY STAR qualified
Best for: Homeowners who prioritize high efficiency and variable-speed comfort.
3. Lennox EL296V — Best Value Two-Stage Furnace
The Lennox EL296V is a strong value-oriented choice in the two-stage category.
Lennox rates the EL296V at up to 96% AFUE and specifies two-stage heating with a variable-speed motor. The company also lists enhanced humidity control, a fully insulated cabinet and ENERGY STAR certification.
That combination makes the EL296V particularly attractive for homeowners who want the benefits of variable-speed airflow without moving into Lennox’s most expensive furnace families.
Pros
- Up to 96% AFUE
- Two-stage heating
- Variable-speed blower
- Quiet operation features
- Enhanced humidity control
- ENERGY STAR certified
Cons
- Not as efficient as the EL297V
- Still more expensive than basic single-stage equipment
- Advanced components can increase repair complexity
Best for: Homeowners looking for a strong balance of price, efficiency and comfort.
4. Carrier Performance 96 59TP6 — Best Carrier Value
The Carrier Performance 96 59TP6 is another strong two-stage option.
Carrier lists the 59TP6 at up to 96.7% AFUE, with two-stage operation and a variable-speed blower. Carrier also states that the furnace can operate in low stage for up to 90% of the time under suitable conditions.
This makes it particularly attractive for homeowners who want many of the comfort characteristics of a premium Carrier furnace without necessarily selecting the top Infinity platform.
Best features
- Two-stage gas valve
- Up to 96.7% AFUE
- Variable-speed blower
- Strong temperature-control potential
- Lower positioning than Carrier’s most premium systems
Best for: Homeowners who like Carrier but want a more value-oriented system.
5. Trane S8X2 / 80 Two-Stage Furnace — Best Simple Two-Stage Design
Trane’s current product information identifies its 80 Two-Stage Gas Furnace as the product formerly known as the S8X2. The manufacturer lists two-stage gas heat, a nine-tap blower motor, a silicon-nitride hot-surface igniter, tubular steel heat exchanger and insulated cabinet.
This furnace is fundamentally different from the high-efficiency condensing models above because it is an 80% AFUE-class system.
That can still make sense in certain replacement applications where a non-condensing furnace is appropriate and the homeowner prioritizes simpler equipment and lower upfront cost.
Pros
- Two-stage operation
- Simple system architecture compared with high-end variable-speed condensing systems
- Insulated cabinet
- Established Trane platform
- Potentially lower installation complexity in suitable replacement applications
Cons
- Lower efficiency than modern 95%+ condensing furnaces
- Not the best choice where maximum fuel efficiency is the priority
- Availability and local code requirements vary
Best for: Homeowners replacing an existing compatible non-condensing system where an 80% two-stage furnace makes sense.
6. Lennox EL297E — Best Two-Stage Furnace With Constant-Torque Blower
The Lennox EL297E provides another approach to high-efficiency two-stage heating.
Lennox lists it at up to 97% AFUE with two-stage heating and a constant-torque blower.
It can be a compelling alternative to a variable-speed model when the homeowner wants high-efficiency two-stage heating but does not require the more advanced airflow capabilities of a variable-speed system.
Variable-Speed vs. Constant-Torque Blowers
The furnace’s blower motor deserves as much attention as its two-stage gas valve.
Variable-speed blower
A variable-speed blower can make very small airflow adjustments and is generally the more sophisticated option.
Potential advantages include:
- Better airflow control
- Quiet operation
- Longer, gentler heating cycles
- Improved humidity-management potential
- Better integration with advanced HVAC controls
Constant-torque blower
A constant-torque ECM blower is simpler than a true variable-speed system but can still provide more controlled airflow than older fixed-speed designs.
For homeowners focused on value, constant-torque systems can provide an attractive middle ground.
Is a Two-Stage Furnace More Efficient?
Potentially, but the answer requires some qualification.
A two-stage furnace can spend more time operating at its lower output. Longer cycles can improve comfort and reduce frequent starts and stops.
However, the furnace’s AFUE rating remains one of the primary standardized efficiency measurements. A two-stage 80% furnace is not automatically more fuel-efficient than a single-stage 96% condensing furnace.
When comparing furnaces, consider both:
- AFUE — how efficiently the furnace converts fuel into heating output.
- Staging — how the furnace adjusts its heating output during operation.
Is Two-Stage Heating Worth the Extra Money?
For many homeowners, yes.
Two-stage operation can be especially worthwhile when:
- You live in a climate with long heating seasons.
- Your home experiences significant temperature swings.
- You want quieter heating.
- You value comfort more than the lowest possible equipment price.
- You plan to keep the furnace for many years.
- You want a variable-speed blower.
However, if your primary goal is minimizing the upfront replacement cost, a basic single-stage furnace may still be appropriate.
Best Two-Stage Furnace for Cold Climates
For cold-weather homes, we would generally prioritize a high-efficiency condensing two-stage furnace.
Look for:
- Approximately 95%–97%+ AFUE
- Two-stage gas valve
- Variable-speed blower where budget permits
- Correct cold-weather sizing
- Reliable local service
- Proper venting and condensate protection
A furnace should be sized for the home’s actual heat loss rather than simply selecting the largest available model.
Best Two-Stage Furnace for the Southern USA
Homeowners in warmer states may not need to spend as much on a high-end furnace.
A 95%–96% AFUE two-stage model can be a very reasonable choice where heating demand is moderate.
In these climates, the additional cost of moving from 96% to 97% or higher may have a relatively long payback depending on local natural-gas prices and annual heating consumption.
What AFUE Should a Two-Stage Furnace Have?
| AFUE | General Recommendation |
|---|---|
| 80% | Consider mainly when a non-condensing system is appropriate |
| 90%–94% | Less attractive where modern high-efficiency options are practical |
| 95%–96% | Excellent balance for many homes |
| 97% | Excellent for higher heating demand |
| 98%+ | Consider when maximum efficiency is economically justified |
Do Two-Stage Furnaces Require Special Thermostats?
Often, yes.
A conventional single-stage thermostat may not provide full control of a two-stage furnace.
Depending on the furnace and control strategy, the system may use a two-stage thermostat, communicating controller or manufacturer-specific control system.
Carrier’s Infinity 96, for example, is designed to work with the Infinity system control for advanced system management.
Ask the contractor exactly which thermostat is included in the quote and whether the furnace’s second stage will actually be controlled properly.
Can a Two-Stage Furnace Improve Air Conditioning?
Potentially.
The furnace’s blower also operates during cooling. A variable-speed blower can provide more sophisticated airflow control and can work with compatible air-conditioning equipment to improve comfort and dehumidification.
Carrier specifically describes the variable-speed blower in its Infinity 96 as operating throughout heating, cooling and continuous-fan operation.
This is one reason it can be worthwhile to evaluate the furnace and air conditioner as one matched system rather than purchasing the furnace in isolation.
Two-Stage Furnace Sizing
Two-stage operation does not eliminate the need for proper sizing.
A contractor should determine the home’s heating requirement using a recognized load calculation rather than relying exclusively on square footage.
Oversizing can still cause problems even when the furnace has two stages.
Problems caused by oversizing
- Short cycling
- Uneven temperatures
- Excessive starts and stops
- Reduced comfort
- Potentially unnecessary operating costs
- More mechanical cycling
A properly sized two-stage furnace should be able to operate at its lower capacity for many normal heating conditions while retaining sufficient high-stage capacity for colder weather.
Two-Stage Furnace Installation Requirements
High-efficiency two-stage furnaces can require substantially more installation work than a basic replacement.
Depending on the model, installation may involve:
- Venting modifications
- Condensate drainage
- Gas-line verification
- Electrical modifications
- Thermostat replacement
- Airflow adjustment
- Ductwork modifications
- Combustion testing
- System commissioning
Do not compare furnace quotes based only on the equipment model.
How Much Does a Two-Stage Gas Furnace Cost?
There is no single nationwide installed price because labor and installation requirements vary considerably.
The final cost depends on:
- Furnace capacity
- AFUE rating
- Brand
- Blower type
- Thermostat
- Venting
- Condensate system
- Ductwork
- Gas-line requirements
- Electrical work
- Local labor costs
- Permits
- Removal of the existing furnace
For this reason, homeowners should obtain multiple detailed installed-system estimates instead of relying on a generic online furnace price.
Two-Stage Furnace Maintenance
Two-stage furnaces require essentially the same fundamental maintenance practices as other gas furnaces, although their additional controls and components can make professional diagnosis more specialized.
- Replace filters regularly.
- Keep return-air openings clear.
- Keep supply registers unobstructed.
- Schedule professional furnace maintenance.
- Inspect the blower and heat exchanger.
- Check combustion and venting.
- Inspect condensate drains on condensing furnaces.
- Keep intake and exhaust pipes clear.
Common Two-Stage Furnace Buying Mistakes
Buying two-stage without checking the blower
A two-stage burner paired with a sophisticated variable-speed blower provides a different comfort experience from a two-stage furnace with a simpler blower.
Ignoring the thermostat
If the control system cannot properly manage both heating stages, you may not receive the full benefit of the equipment.
Buying based only on AFUE
AFUE matters, but staging, blower technology, sizing and installation quality matter too.
Choosing the biggest furnace
More capacity is not better if the furnace is substantially oversized for the home.
Choosing the cheapest installer
A high-end furnace can perform poorly when installed incorrectly. Contractor quality should be one of the biggest factors in the purchase decision.
How to Choose the Best Two-Stage Gas Furnace
- Calculate the home’s heating load.
- Determine whether natural gas or propane will be used.
- Decide whether a condensing furnace is appropriate.
- Compare 95%–97%+ AFUE options.
- Compare variable-speed and constant-torque blower systems.
- Check thermostat compatibility.
- Evaluate existing ductwork.
- Compare warranties.
- Get at least two or three installation quotes.
- Choose the contractor with the strongest installation and service capability.
Our Two-Stage Furnace Recommendations
| Category | Our Pick | Why |
|---|---|---|
| Best Overall | Carrier Infinity 96 59TN6 | Excellent combination of two-stage heat, variable-speed airflow and premium controls |
| Best High Efficiency | Lennox EL297V | Up to 97% AFUE with two-stage and variable-speed operation |
| Best Value | Lennox EL296V | Up to 96% AFUE with two-stage heating and variable-speed blower |
| Best Carrier Value | Carrier Performance 96 59TP6 | High efficiency and variable-speed operation at a lower tier than Infinity |
| Best Simpler System | Trane S8X2 / 80 Two-Stage | Two-stage operation without the complexity of a high-efficiency condensing system |
Frequently Asked Questions
Are two-stage gas furnaces worth it?
For many homeowners, yes. Two-stage operation can improve comfort by allowing the furnace to operate at a lower output for many heating calls. The benefit is greatest when the furnace is properly sized and installed.
Is a two-stage furnace better than a single-stage furnace?
Generally, a two-stage furnace provides better comfort and operating flexibility, but it costs more. A single-stage model can still be appropriate for budget-focused installations.
What is the best two-stage furnace brand?
There is no universal winner. Carrier, Lennox and Trane all offer strong two-stage products. The exact model, installer and local service support are more important than the brand name alone.
Is a 96% two-stage furnace good?
Yes. A 96% AFUE two-stage furnace is a strong efficiency and comfort combination for many U.S. homes.
Is a variable-speed furnace better than a two-stage furnace?
These terms describe different components. “Two-stage” refers primarily to the heating output, while “variable-speed” usually refers to the blower motor. A furnace can have both.
Does a two-stage furnace save gas?
It can reduce unnecessary high-output operation and improve system operation, but actual fuel savings depend on the furnace’s AFUE, sizing, climate, thermostat settings, home efficiency and installation.
Can I use my existing thermostat with a two-stage furnace?
Sometimes, but it depends on the thermostat and furnace. A two-stage system may require a compatible two-stage or communicating thermostat to use both heating stages properly.
What is better: 80% two-stage or 96% single-stage?
For fuel efficiency, the 96% furnace has a major advantage. However, an 80% two-stage furnace may make sense in specific replacement situations where a non-condensing system is appropriate.
Do two-stage furnaces run longer?
They can. Operating at a lower heating output allows the furnace to run longer during many heating calls, which can improve temperature consistency.
What is the best two-stage furnace for a cold climate?
A high-efficiency condensing model with two-stage heat and a variable-speed blower is generally the type to investigate first. The Carrier Infinity 96 and Lennox EL297V are strong examples.
What is the best two-stage furnace for a budget-conscious homeowner?
A 95%–96% AFUE two-stage furnace can provide an excellent balance of efficiency and comfort without the cost of a premium modulating system. The Lennox EL296V is one example of this category.
Final Verdict
A two-stage gas furnace is an excellent middle ground between a basic single-stage furnace and a premium modulating system.
For most homeowners who prioritize comfort, efficiency and reasonable system complexity, we would start with a 95%–97% AFUE two-stage furnace paired with a variable-speed blower.
The Carrier Infinity 96 59TN6 is our top overall choice because it combines two-stage heating, variable-speed airflow and premium controls, with Carrier listing efficiency up to 96.7% AFUE.
The Lennox EL297V is particularly attractive for homeowners seeking up to 97% AFUE with two-stage and variable-speed operation.
The Lennox EL296V is a strong value option, offering up to 96% AFUE, two-stage heating and variable-speed airflow.
For homeowners who want a simpler two-stage solution and have a suitable existing non-condensing installation, the Trane S8X2 / 80 Two-Stage is another option to discuss with a qualified contractor.
Ultimately, don’t choose a furnace simply because it has two stages. Correct sizing, proper ductwork, compatible controls and professional installation are just as important as the furnace’s model number.
Official Manufacturer and Certification Resources
Carrier Infinity 96 59TN6 — manufacturer specifications and features.
Lennox EL296V — manufacturer specifications and features.
Trane 80 Two-Stage / S8X2 — manufacturer specifications.
About the Author
ManBearPig is a part-man, part-bear, part-pig creature and a full-time expert on global warming—mostly because he has personally experienced the consequences of being extremely, extremely, super cereal.
When he isn’t roaming the wilderness, terrorizing unsuspecting humans, or demanding that people take climate change seriously, ManBearPig studies rising temperatures, melting ice, extreme weather, carbon emissions, and other inconvenient signs that the planet may not be particularly happy with us.
His research philosophy is simple:
“I’m super cereal.”
ManBearPig believes climate change is too important to discuss without facts—and too ridiculous to discuss without a little humor. Through this website, he explores global warming, climate science, environmental changes, energy, and the strange ways humans respond when their own planet starts sending them warning signals.
He has no university degree, no laboratory, and absolutely no intention of becoming a respectable academic.
But he does have hooves, claws, a snout, and an unusually strong opinion about melting ice.