SEER Energy Savings Calculator

How Does the Calculator Work?

The calculator’s primary purpose is to help you compare the cooling costs of two air conditioners or heat pumps by using their SEER/SEER2 ratings, and to estimate your annual savings.

First, the calculator estimates your annual home cooling costs based on four factors:

• the SEER rating of your current air conditioner (learn how to find your AC’s SEER rating),
• Your air conditioner’s size (in tons),
• the cost of electricity per kilowatt-hour (Kwh) in your state, and
• the annual cooling hours for your location (estimated with weather data from ASHRAE, 2017).

Next, the calculator compares your home’s estimated annual cooling costs with the cooling costs of a higher efficiency air conditioner.

Then, you can see how much an AC with a higher SEER2 rating could save you per year in cooling costs. The air conditioner energy calculator also displays your projected cumulative savings over a 1-year, 5-year, 10-year and a 15-year period. In most cases, the potential savings are pretty amazing!

What is SEER and SEER2?

SEER is the rating system for air conditioner and heat pump energy efficiency. It stands for Seasonal Energy Efficiency Ratio. The higher the number, the less electricity the air conditioner or heat pump consumes.

SEER2 is the upgraded version of SEER. SEER2 became the new standard energy efficiency rating system for air conditioners and heat pumps on January 1, 2023. All new air conditioner models manufactured from 2023 on will carry a SEER2 rating.

How are SEER and SEER2 Ratings Calculated?

SEER is the calculated in the following way:

The total amount of heat removed from a home during a typical annual cooling season (expressed in British thermal units (BTU¹))

divided by

The total electrical energy the air conditioner or heat pump system used during the same cooling season (expressed in watt-hours (Wh))².

SEER2 uses this same calculation as SEER. The difference between SEER and SEER2 ratings lies in the testing procedures.

Each air conditioner must undergo testing to determine its efficiency rating. On January 1, 2023, new testing requirements came into effect, which include some adjustments to account for actual field conditions. For instance, manufacturers are now required to test air conditioners and heat pumps under higher external static pressure.

The result is a more accurate representation of a unit’s energy consumption in the real world. However, the SEER rating a unit achieves under the new testing procedures is approximately 4.5% lower than the rating it would have received under the old testing requirements. To differentiate units tested under the old and new requirements, the new efficiency rating is referred to as SEER2.

Comparing SEER and SEER2 is a bit like comparing apples and oranges. However, a SEER2-rated system is roughly 4.71% more efficient than a SEER system with the same rating number. To test this out on the SEER Savings Calculator, try setting the SEER and SEER2 sliders so the number on both sliders is the same. (The resulting energy cost savings estimates will round up to the next whole percentage point.)

For a more in-depth explanation of SEER2 calculations and testing requirements, feel free to hunker down for some further reading in the following document: AHRI Standard 210/240 (210/240-2023)

¹A British thermal unit (Btu) is essentially a unit of heat. 1 Btu is equivalent to the amount of heat it takes to raise the temperature of one pound of water by one degree Fahrenheit.

² US DEPARTMENT OF ENERGY (DOE), 10 CFR Parts 429 and 430, [Docket No. EERE-2016-BT-TP-0029] RIN 1904-AD71, Energy Conservation Program: Test Procedures for Central Air Conditioners and Heat Pumps, page 194

A Note About HSPF and EER

We should also note two other HVAC energy efficiency acronyms you might come across – HSPF and EER. While these are not mentioned on our AC energy savings calculator, it’s important to know what they mean.

HSPF (Heating Seasonal Performance Factor) and HSPF2

Heat pumps have an HSPF rating in addition to a SEER rating. HSPF (Heating Seasonal Performance Factor) rates a heat pump’s heating efficiency. The only difference between a heat pump and an air conditioner is that a heat pump can provide both heating and cooling. A heat pump cools your home by transferring warm air from the inside to the outside, and it heats your home by transferring warm air from the outside to the inside.

Like SEER, HSPF is calculated by dividing the total BTU¹ required to heat your home during a typical season by the total watt-hours of electricity the heat pump consumes during that same season.

Also like SEER, HSPF underwent changes to the rating system in 2023. We won’t go into details here, but suffice to say that all heat pumps manufactured in 2023 and beyond will have an HSPF2 rating, replacing the former HSPF rating.

Use our AFUE Savings Calculator to learn more about HSPF and heat pump energy efficiency.

EER (Energy Efficiency Ratio) and EER2

EER, standing for Energy Efficiency Ratio, is also a measurement of air conditioner or heat pump energy efficiency. Starting January 1, 2023, EER2 is the updated version of EER.

EER2 is calculated in a nearly identical manner to SEER2 (BTU/Wh). However, the main difference between the two is that SEER2 accounts for changes in the average outdoor temperature and EER2 does not. EER2 is based on a constant outdoor temperature of 95° F. On the other hand, SEER2 calculations are based on outdoor temperatures ranging from 65°F to 104°F.

Because SEER2 factors in seasonal performance, it is considered the standard rating system. EER2’s specific temperature scenario has limited real-world application, making it less useful as a measure of actual efficiency.

What are the Current Air Conditioner Efficiency Standards?

There are national energy efficiency standards for all air conditioners and heat pumps sold and installed. The latest update to these standards went into effect on January 1, 2023.

The new standards require a higher minimum efficiency rating than the previous standards. The map and chart below show the current minimum energy efficiency ratings by region. Because these new standards also coincide with the rollout of the upgraded SEER2 rating systems (discussed above), we included both the minimum SEER and SEER2 ratings for ease of comparison.

*Southeast includes: The states of Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, Puerto Rico, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, and the U.S. territories.
**Southwest includes the states of Arizona, California, Nevada, and New Mexico.
***The 10.2 EER (9.8 EER2) amended energy conservation standard applies to split-system air conditioners with a SEER rating greater than or equal to 16.
†The energy conservation standards for single-package, small-duct high-velocity and space-constrained product classes remain unchanged from current levels.

If your current air conditioner or heat pump doesn’t meet the minimum requirements listed above, don’t panic. You can still own an air conditioner with less than the minimum SEER/SEER2 rating. However, HVAC contractors are not allowed to install systems that do not meet the new standards (with a few exceptions). It may come as a relief to know that you don’t immediately have to replace your 14 SEER (or less) system if it’s still running. However, we encourage you to use our calculator to compare your current AC with a higher efficiency system. You might be surprised how much electricity you can save by upgrading!

How Do I Find My Air Conditioner’s SEER or SEER2 Rating?

There should be a yellow Energy Guide label adhered to the body of your condensing unit.

If you’re unsure of your air conditioner’s efficiency rating, here are a couple ways you can easily find it:

• Go outside and look at your condenser unit. Many newer air conditioners have a large, yellow sticker on the side that clearly states the SEER rating along with some other specs.
• If your unit doesn’t have a yellow sticker, or if the sticker is too weather-beaten to be legible, try looking at your air handler. The air handler is probably somewhere inside your home, in the attic, or in your garage. There might be a sticker on it with some information about your unit, including the SEER rating.
• You can try locating your air conditioner’s manufacturer, model number and the serial number. This information should be written somewhere on the condenser or the air handler. You can then go online to the  manufacturer’s website and look up the model/serial number. If you can’t find the information by searching, you can always try calling the manufacturer’s customer service hotline.

Mismatched Systems

Your air conditioner’s condenser and air handler must match for the unit to perform at its potential efficiency.

What do we mean by “match”? Most manufacturers make their air handlers compatible only with certain condensers for optimal performance. HVAC contractors are generally required to install air conditioners in these matched sets, but this unfortunately does not always happen.  If your unit is mismatched, it’s unlikely that it will achieve the SEER or SEER2 efficiency promised on its label. Rats!

What is AC Tonnage?

We know what you might be thinking – and no, tonnage does not refer to the physical weight of your air conditioner. Although tonnage is often referred to as the AC’s “size”, this really means its cooling capacity. More specifically, it tells how much heat the unit can remove from your house in one hour. For instance, a one-ton air conditioner can remove 12,000 Btu’s of heat from your house in one hour’s time. A two-ton air conditioner can remove 24,000 Btu’s, and so on.

So, what size of air conditioner do you need to effectively cool your home? That depends on various factors such as your home’s square footage, the number of occupants and the number of windows. Here’s a chart containing some of the typical AC sizes by square footage. If your home is larger than these examples, you may need multiple air conditioners working simultaneously. Anything over a 5-ton air conditioner is considered a commercial size and is not available for residential use.