Will Upgrading Your Furnace Save Money on Energy Bills in Des Moines?

Upgrading your furnace can help lower energy bills, improve indoor comfort, and reduce operating noise. However, replacing a relatively new high-efficiency furnace may not always provide enough savings to justify the cost.

We receive many calls from Des Moines homeowners asking whether they should upgrade from a 90% to a 96% efficiency gas furnace. Before making the change to a variable-speed furnace, you should consider the age of your current system, its condition, the type of blower motor it uses, and how much you could realistically save each year.

Let’s take a closer look.

Advantages and Disadvantages of a Variable-Speed Furnace

Having a high-efficiency furnace can help protect your household from unnecessarily high utility bills during the cold Iowa winter. A high-efficiency furnace generally has an Annual Fuel Utilization Efficiency, or AFUE, rating of 90% or higher.

What does a 90% furnace efficiency rating mean? If a furnace has a 90% AFUE rating, approximately 90% of the fuel it consumes is converted into usable heat. The remaining 10% is lost during the heating process.

A 96% efficient furnace converts approximately 96% of its fuel into heat. While that is more efficient, the difference between 90% and 96% may not always produce substantial savings.

If you already have a furnace with an efficiency rating of 90% or higher and it is 10 years old or less, upgrading to a 96% efficient furnace may not make financial sense. Depending on the size of the furnace, the condition of your home, and your heating habits, the improvement in fuel efficiency may only save approximately $50 to $100 per year.

Those savings may be relatively small compared to the total cost of purchasing and installing a new furnace.

However, fuel efficiency is only one part of the equation. When evaluating the overall energy consumption of a furnace, you also need to consider how much electricity the system uses to circulate warm air throughout your home. The type of blower motor inside the furnace can make a significant difference in electrical consumption.

Two Primary Types of Gas Furnace Blower Motors

Standard Furnace Motor

Many 90% efficient furnaces installed since the 1980s use a standard, single-speed blower motor. This means the blower generally operates at one speed—typically its highest setting—whenever the furnace turns on.

A single-speed motor may create a sudden and noisy blast of air from the vents. It also repeatedly turns on and off as the thermostat calls for heat, which can result in temperature fluctuations throughout the home.

Older standard blower motors are usually larger and consume more electricity than the advanced motors used in many modern furnaces. Even when an older furnace has a relatively high AFUE rating, an inefficient blower motor may increase its overall operating costs.

Variable-Speed Furnace Motor

A variable-speed blower motor can operate at different speeds to more precisely control the flow of heated air throughout your home. It continuously responds to information from your heating system, cooling system, and thermostat to meet your comfort needs.

Instead of immediately operating at full power, a variable-speed motor gradually increases its speed. This can eliminate the sudden, noisy blast of air associated with many standard furnace motors.

Because the blower can run at lower speeds when full power is unnecessary, a variable-speed furnace motor may use significantly less electricity than a standard motor. It can also circulate air for longer periods while consuming less energy.

Other potential benefits of a variable-speed furnace include:

• More consistent temperatures throughout your home
• Quieter furnace operation
• Improved indoor air circulation
• Better filtration of airborne particles
• More efficient heating and cooling performance
• Reduced electrical consumption compared to older blower motors

Is Upgrading to a Variable-Speed Gas Furnace Worth It?

If you are planning to upgrade from a 90% to a 96% efficient furnace, make sure the new system includes a variable-speed blower motor. The reduction in gas consumption alone may not be enough to recover the cost of replacing a furnace that is still relatively new and operating correctly.

However, combining a higher AFUE rating with a variable-speed motor can reduce both natural gas and electrical consumption. Depending on your current equipment, the size of your home, local utility rates, and how frequently you use the furnace, the combined energy savings could be more meaningful.

Upgrading may also make sense when your existing furnace:

• Requires frequent or increasingly expensive repairs
• Is approaching the end of its expected service life
• Produces unusual noises during operation
• Struggles to maintain the thermostat setting
• Leaves certain rooms colder than others
• Causes noticeable increases in your utility bills

Comfort should also be part of the decision. A variable-speed furnace may deliver more even heating throughout your home, operate more quietly, and reduce noticeable temperature swings. These benefits may make an upgrade worthwhile even when the annual energy savings alone do not immediately cover the installation cost.

Consider Your Ductwork and Furnace Installation

Even the most efficient furnace will not deliver its expected performance if it is improperly sized or connected to damaged ductwork. Leaking, poorly insulated, or incorrectly designed ducts can allow heated air to escape before it reaches your living spaces.

An oversized furnace may turn on and off too frequently, while an undersized furnace may struggle to keep your home warm. Both situations can increase energy consumption and reduce comfort.

Before upgrading your furnace, have a qualified HVAC professional inspect your current system, evaluate the condition of your ductwork, and perform the appropriate load calculations. A professional assessment can help determine whether replacing the furnace, repairing the existing system, or improving the ductwork will provide the best return on your investment.

Should You Upgrade Your Furnace?

Let’s recap:

• If your current furnace has an efficiency rating below 90%, upgrading to a modern high-efficiency system may help reduce your energy costs.
• If your 90% efficient furnace is 10 years old or less and still operates reliably, replacing it solely for a 96% AFUE rating may not provide enough savings to justify the expense.
• If you choose a 96% efficient furnace, look for one with a variable-speed blower motor to maximize potential energy savings and comfort.
• Consider the age, repair history, blower motor, ductwork, installation quality, and overall performance of your existing system before making a decision.

The best way to determine whether upgrading your furnace will save money is to compare the installation cost with your estimated annual energy savings. A professional furnace evaluation can give you a clearer understanding of your options and help you select the right heating system for your Des Moines home.

Learn more: Do This Before Turning On Your Furnace.