What does AFUE Mean? What is a SEER Rating?
Understanding SEER and AFUE Ratings: What Homeowners Need to Know
At Aquarius Home Services, we believe in empowering our customers with the knowledge to make informed decisions about their home systems. Two terms you’ve likely encountered when shopping for HVAC (Heating, Ventilation, and Air Conditioning) equipment are SEER (Seasonal Energy Efficiency Ratio) and AFUE (Annual Fuel Utilization Efficiency). But what do these ratings mean, and how do they impact your home’s comfort and energy bills? Let’s break it down.
What Is a SEER Rating?

SEER, or Seasonal Energy Efficiency Ratio, measures the efficiency of air conditioners and heat pumps. It indicates how much cooling a unit provides over a typical cooling season compared to the amount of energy it consumes.
- How It’s Calculated: SEER is calculated by dividing the total cooling output during a typical cooling season by the total energy input (measured in watt-hours) during the same period.
- What It Means for You: The higher the SEER rating, the more efficient the air conditioner or heat pump. Unlike AFUE, SEER is not a percentage so the differences on the scale are not easy to calculate.
Why It Matters: An energy-efficient system reduces electricity usage, which translates to lower utility bills and a smaller environmental footprint.
What Is an AFUE Rating?

AFUE, or Annual Fuel Utilization Efficiency, measures the efficiency of furnaces and boilers. It indicates how effectively these systems convert fuel into heat over a typical year.
- How It’s Calculated: AFUE is expressed as a percentage. For example, a furnace with a 90% AFUE converts 90% of the fuel into usable heat, while the remaining 10% is lost through exhaust or other inefficiencies.
- What It Means for You: The higher the AFUE rating, the more efficiently the system uses fuel, saving you money on heating costs.
Why It Matters: Systems with high AFUE ratings not only save money but also reduce greenhouse gas emissions by using fuel more efficiently.
How Much Can You Save with Energy Efficient Equipment?
How much will I save on my energy bills?
Giving a specific answer to this question depends on several factors:
- The efficiency rating of your current equipment
- Energy prices in your area
- Your energy usage
- The service life of the equipment
In order to make the best financial decision, homeowners should find the Savings to Investment Ratio for their specific situation.
Let’s use a simplified hypothetical situation as an illustration of annual savings:
A Wisconsin homeowner has a furnace with an AFUE rating of 80%. They’re considering installing a new furnace with a 96% AFUE rating. They currently pay $1200/ year on their natural gas bill.
The first thing you can calculate is the yearly financial savings.
([Current bill] x [current efficiency]) / [New efficiency] = [New bill]
($1200 x 80)/ 96 = $1000
Then find the difference between the old bill and new bill.
$1200- $1000 = $200 in annual savings
Let’s say the homeowner is also considering a 98% AFUE furnace.
($1200 x 80)/ 98 = $979
$1200-$816= $221 in annual savings
As you can see, upgrading from an old, inefficient furnace to a high efficiency model can mean big savings on your energy bills!
How long will it take for energy efficient equipment to pay for itself?
The answer to this question depends on yet more variables:
- The cost of the equipment
- The service life of the equipment
- The annual savings you will achieve
- Rebates, credits and incentives
With these variables incorporated, you can now calculate your Savings to Investment Ratio
Savings to Investment Ratio (SIR) compares a purchase price to savings achieved.
A SIR of greater than 1 means you’re saving more than you’re spending. Less than 1 means spending more than you’re saving.
Let’s go back to our illustration:
The Wisconsin homeowner is considering a 96% AFUE furnace that costs $4500. They are expecting to get 15 years out of this furnace, which is a very normal service life. We can use that investment to calculate our Savings to Investment Ratio (SIR).
[Annual savings] x [service life] = total savings
[total savings]/[equipment cost] = SIR
$200 x 15 = $3000 in savings
$3000/$4500 = 0.67 SIR
Increase the service life to 20 years
$200 x 20 = $4000
4000/4500= 0.88 SIR
Now change to a 98% AFUE furnace that costs $4800
$221 x 15 = $3315
3315/4500 = 0.73
Remember that this is only a hypothetical situation.
To make calculations specific to your situation, try out these helpful calculator tools:
Energy Efficiency Tax Credits and Rebates
The SIR illustration only tells part of the story. As you can see, the energy savings alone were not enough to cover the cost of the equipment purchase. The calculus changes in a big way when you factor in tax credits and rebates.
The Inflation Reduction Act of 2021 provides generous incentives for homeowners who invest in energy-efficient systems. Additionally, many local utilities also offer one-time rebates for upgrading to high efficiency equipment. Here’s what you need to know:
- Qualifying Equipment:
- Air conditioners with a SEER rating of 15.2 or higher.
- Heat pumps with a SEER rating of 15.2 or higher
- Furnaces with an AFUE of 97% or higher
- Credit Amount:
- Heat Pumps – $2,000 in tax credits. Rebates vary by utility company.
- High efficiency furnaces – $2000 in tax credits. Rebates vary by utility company.
- Air conditioners – $600 in tax credits. Rebates vary by utility company.
- How to Claim: Keep receipts and documentation of the equipment’s ratings and consult with a tax professional to claim the credit on your federal tax return.
Investing in energy-efficient HVAC equipment not only helps reduce your utility bills but also makes you eligible for these valuable financial incentives. For more details, check out our blog on energy tax credits.
Making the Right Choice for Your Home
When selecting HVAC systems, balancing efficiency with upfront costs is essential. While higher SEER and AFUE ratings often mean a higher initial investment, the long-term energy savings combined with tax credits and utility rebates will typically offset the difference.
At Aquarius Home Services, our team is here to help you find the best system for your needs and budget. Whether you’re upgrading an old unit or building a new home, we’ll guide you through the process to ensure your home is comfortable and energy-efficient.
Why Choose Aquarius Home Services?

At Aquarius Home Services, we’re committed to providing exceptional service and high-quality HVAC systems. Our expert technicians will:
- Evaluate your home’s specific needs.
- Recommend systems with the best SEER and AFUE ratings for your situation.
- Ensure professional installation and ongoing maintenance to maximize efficiency.
- Help you navigate the process for claiming tax credits and utility rebates.
Investing in the right HVAC systems is an investment in your home’s future. With a clear understanding of SEER and AFUE ratings, you can make confident, informed decisions to keep your home comfortable year-round while saving money and energy.
Contact us today to learn more about how we can help you achieve a more comfortable and energy-efficient home.