High-Efficiency Furnaces in Elmhurst, IL

What Is a High-Efficiency Furnace?

Furnace efficiency is measured using AFUE, or Annual Fuel Utilization Efficiency.

AFUE represents how much of the fuel used by a furnace is converted into usable heat for your home.

For example:

• An 80% AFUE furnace converts approximately 80% of its fuel into heat.
• A 95% AFUE furnace converts approximately 95% into heat.
• A 97% AFUE furnace converts approximately 97% into heat.

The remaining energy is lost during the combustion and venting process.

High-efficiency gas furnaces are generally considered furnaces with an AFUE rating of 90% or higher. Many modern high-efficiency furnaces fall into the 95% to 98% AFUE range.

Higher AFUE means less fuel is wasted, but efficiency is only one part of choosing the right furnace.

Is a High-Efficiency Furnace Worth It in Illinois?

For many homeowners in the Chicago area, a high-efficiency furnace can make a lot of sense.

We have a long heating season, and a furnace may operate for many months each year. Increasing efficiency can reduce the amount of natural gas required to heat your home.

But there is no single furnace that is right for every house.

When we help a homeowner compare furnace options, we consider factors such as:

• The efficiency of the existing furnace
• The size and condition of the home
• How long the homeowner expects to remain in the house
• Existing ductwork and airflow
• Furnace location
• Venting requirements
• Chimney configuration
• Comfort concerns
• Initial equipment and installation cost
• Available utility rebates or incentives

Replacing an older, lower-efficiency furnace with a modern high-efficiency system can provide a significant improvement. In other situations, the difference between two already-efficient furnaces may be less important than equipment staging, blower performance, proper sizing, or installation quality.

We would rather help you choose the furnace that fits your home than simply sell you the highest efficiency number available.

High-Efficiency Furnace vs. 80% Furnace

One of the biggest differences between an 80% furnace and a high-efficiency furnace is what happens to the heat produced during combustion.

An 80% furnace sends relatively hot exhaust gases through a metal flue pipe and typically vents through a chimney.

A high-efficiency condensing furnace captures additional heat from the exhaust before it leaves the furnace. As the exhaust cools, water vapor condenses into liquid water.

Because of this, high-efficiency furnaces normally require:

• PVC or approved plastic vent piping
• A combustion air intake and exhaust system
• A condensate drain
• Additional internal components to recover heat from the combustion gases

This allows the furnace to use more of the heat produced by the fuel instead of sending it outside through the flue.

Furnace Venting and Your Existing Chimney

Changing from an 80% furnace to a high-efficiency furnace may also change how your home’s chimney is used.

A high-efficiency furnace is normally vented directly outdoors rather than through the existing masonry chimney.

If a conventional atmospheric water heater also vents through that chimney, removing the furnace can change the venting conditions for the remaining water heater.

That does not mean a high-efficiency furnace cannot be installed. It simply means the entire venting system needs to be evaluated as part of the job.

Depending on the home, options may include modifying the chimney venting, installing an appropriate chimney liner, or using a different type of water heater.

Proper venting is part of proper furnace installation.

Single-Stage, Two-Stage, and Modulating Furnaces

Efficiency is not the only difference between modern furnaces.

How a furnace produces heat can have a major effect on comfort.

Single-Stage Furnaces

A single-stage furnace operates at full heating capacity whenever there is a call for heat.

It is a simple and proven design and can be a good option for many homes when properly sized.

Two-Stage Furnaces

A two-stage furnace can operate at a lower heating output during milder conditions and increase to full capacity when additional heat is needed.

Because a properly sized furnace may spend much of the heating season operating on its lower stage, it can run for longer cycles with more even temperatures throughout the home.

Potential benefits include:

• More consistent room temperatures
• Longer, quieter heating cycles
• Less noticeable temperature swings
• Improved comfort during milder weather

Modulating Furnaces

A modulating furnace can adjust its heating output through a wider range rather than operating at only one or two fixed stages.

This allows the furnace to more closely match the heating needs of the home as outdoor conditions change.

For homeowners who place a high priority on comfort and temperature consistency, a modulating furnace may be worth considering.

Variable-Speed and ECM Blower Motors

Modern furnaces may also use electronically controlled blower motors rather than traditional single-speed motors.

Depending on the furnace and system design, these motors can adjust airflow for different operating conditions.

Potential advantages include:

• Quieter operation
• More consistent airflow
• Better temperature control
• Improved air circulation
• Better control when paired with multi-stage heating and cooling equipment
• Lower electrical consumption compared with some older blower motor designs

The blower motor is also responsible for moving air during air conditioning season, so furnace blower selection can affect the performance of the entire HVAC system.

Proper Furnace Sizing Matters

A higher-efficiency furnace will not solve problems caused by improper sizing.

Installing an oversized furnace can cause short heating cycles, temperature swings, unnecessary noise, and reduced comfort.

A furnace should be selected based on the heating needs of the home, not simply by replacing the old furnace with another unit of the same input capacity.

Many older furnaces were oversized when originally installed. Improvements made to a home over the years, including new windows, insulation, or air sealing, can also change its heating requirements.

Proper equipment selection should consider the home itself along with the furnace.

Learn about our furnace installation services.

Your Ductwork Matters Too

Even the best furnace cannot provide good comfort if the duct system cannot properly move air throughout the home.

During a furnace replacement, we may identify issues such as:

• Undersized return air
• Restricted ductwork
• Poorly designed transitions
• Inadequate supply airflow
• Filter restrictions
• Duct leakage
• Rooms that consistently receive too much or too little airflow

We operate our own sheet metal shop and can make ductwork modifications when needed as part of a furnace installation.

Sometimes improving the duct system can make as much difference in comfort as upgrading the equipment itself.

ENERGY STAR High-Efficiency Furnaces

ENERGY STAR establishes efficiency requirements that equipment must meet to earn the ENERGY STAR certification.

For gas furnaces installed in northern states such as Illinois, the current ENERGY STAR furnace standard is 97% AFUE or greater.

That does not mean every furnace installed in Illinois must be 97% efficient.

It simply means a gas furnace must meet the applicable ENERGY STAR efficiency requirements if the manufacturer wants that furnace to carry the ENERGY STAR certification.

Whether an ENERGY STAR certified furnace is the right choice for your home depends on your equipment options, installation requirements, budget, and comfort goals.

Rheem High-Efficiency Furnaces

Unlimited Heating & Cooling has installed Rheem heating and cooling equipment for decades.

Rheem offers several furnace efficiency and comfort options, including high-efficiency two-stage and modulating furnaces.

Rather than pushing a particular model before seeing the home, we prefer to evaluate the application first and then recommend equipment that fits the job.

The right furnace depends on much more than the name on the cabinet.

Proper sizing, airflow, venting, controls, ductwork, and installation all affect how the system performs after it is installed.

Furnace Rebates and Incentives

Utility rebates may be available for qualifying high-efficiency furnace installations.

Programs and eligibility requirements can change, so we recommend checking current incentives when considering a furnace replacement.

We can also help determine whether the equipment being quoted meets the requirements of applicable utility rebate programs.

Why Choose Unlimited Heating & Cooling?

Unlimited Heating & Cooling has served Elmhurst and surrounding communities since 1984.

We are a local, family-owned HVAC company that believes homeowners should understand what they are buying and why it is being recommended.

When replacing a furnace, we focus on:

• Proper equipment sizing
• Honest equipment recommendations
• Upfront pricing
• Quality installation
• Proper airflow and ductwork
• Safe venting and combustion
• Clean, professional workmanship
• Reliable service after the installation

We install equipment to perform properly in your home, not simply to replace the box that was there before.

We also provide furnace repair and furnace maintenance to keep your heating system dependable.

Frequently Asked Questions About High-Efficiency Furnaces

What furnace efficiency should I buy?

There is no single efficiency rating that is best for every home. Your existing furnace, heating costs, installation requirements, budget, comfort goals, and how long you plan to stay in the home should all be considered.

We can show you the available options and explain the differences before you decide.

Is a 97% furnace required in Illinois?

No. A 97% AFUE rating is part of the current ENERGY STAR certification requirement for gas furnaces in the northern United States, including Illinois. It does not mean every furnace installed in Illinois is required to be 97% efficient.

Does a high-efficiency furnace need a chimney?

Typically, no. High-efficiency condensing furnaces generally vent through approved plastic piping directly outdoors.

However, if another appliance such as a conventional water heater continues to use the existing chimney, that venting system still needs to be evaluated.

Does a high-efficiency furnace need a drain?

Yes. High-efficiency condensing furnaces produce water as part of the heat-recovery process. That condensate must be safely drained or pumped to an appropriate location.

Is a two-stage furnace more efficient than a single-stage furnace?

Not necessarily simply because it has two stages. AFUE measures the furnace’s fuel efficiency.

Two-stage operation primarily provides better control over heating output and can improve comfort by allowing the furnace to operate at a lower capacity when the full heating output is not needed.

Is a 98% furnace always better than a 95% furnace?

It is more efficient at converting fuel into usable heat, but that does not automatically make it the best choice for every home.

The difference in equipment cost, venting, system design, comfort features, expected fuel savings, and how long you plan to own the home should all be considered.

How long does a furnace replacement take?

Many straightforward furnace replacements can be completed in one day. Installations that require significant ductwork modifications, venting changes, zoning work, or other system improvements may take longer.

We can explain the scope of the installation before work begins.