EER to SEER Calculator: How to Convert for ACs (With Charts)

SEER Label

Roughly three-fourths of all US houses have air conditioners because of the ever-changing weather conditions. However, not all air conditioners are created equal; some are more efficient than the rest.

Therefore, to determine which unit is more efficient than another, you will have to consider their EER and SEER ratings.

During summers, households consume more electricity than in winter to maintain inside cooling. So if you don’t have an efficient unit, you will have to pay hefty utility bills.

If you plan to upgrade or buy a new air conditioner, consider the EER and SEER ratings to calculate its efficiency.

To know more about these ratings and how to convert EER to SEER rating, read on:

How To Calculate The EER Rating Of My AC

The Energy Efficiency Ratio – sometimes also called EER or Energy Efficiency rating – is a value used to calculate an HVAC system’s energy efficiency, particularly smaller AC units.

Simply put, the EER rating gives you a ratio (value) of cooling output to electricity consumed. You can find it on the yellow & black energy guide sticker located within the unit’s condenser.To calculate the EER of your AC unit, the formula is:

EER = Capacity (BTU) / Power (Wattages)

Suppose you have a 12,000 BTU air conditioner that consumes 1000 W. Put both values into the EER formula:

EER = 12000/1000 = 12

AC units with higher EER ratings are more efficient!

Related Article What Is EER Rating?

How To Calculate The SEER Rating Of My AC

The Seasonal Energy Efficiency Ratio, sometimes called SEER or Seasonal Energy Efficiency Rating, is used mainly for centralized HVAC systems. It’s a ratio (value) of the unit’s cooling output over an entire cooling season to the energy consumed.

Like the EER rating, you can locate any unit’s SEER rating on the energy guide sticker placed inside the condenser.To calculate the SEER rating of an air conditioner, the equation is:

SEER = Capacity (BTU) x 1000 / Power (wattages) x 1000

Suppose you have an AC unit with 14,000 BTU cooling power. It uses 1000 W of electricity. Put these values into the SEER rating equation:

SEER = 14000×1000 / 1000×1000 = 14,000,000/ 1,000,000 = 14

Related Article What Is SEER Rating?

How To Convert EER To SEER

While EER gauges energy performance at 50% humidity, 100% cooling-load, and 80°F to 95°F temperature difference, on the other hand, SEER measures energy performance during the entire summer from June to August.

You can convert EER to SEER ratings using the universal EER equation recommended by AHRI (Air conditioning, Heating, and Refrigeration Institute).Here’s a formula to convert EER to SEER:

EER = 0.875 x SEER

Since we have to find SEER rating using the EER equation, the formula will be:

SEER = EER / 0.875

Let’s suppose you have an EER rating of 12, which you have taken using the ‘EER = capacity/ wattage’ formula. Put the value 12 into the SEER equation, and you’ll get the SEER value:

SEER = 12 / 0.875 = 13.7

You can also use the ‘EER to SEER’ conversion chart to know the SEER value if you don’t want to do the math.

EEER to SEER Rating

Apart from that, the online EER to SEER converter may also prove handy when buying an AC unit or heat pump.

The converter is easy to use: all you have to do is input your EER ratings, and that’s all — you’ll have your SEER rating in no time!

EER Vs. SEER: When To Use Each

Now that you know about EER and SEER, here’s when you can use each:

SEER ratings can commonly be used for comparing one air conditioner or heat pump with another.

It’s mostly used for big centralized air conditioning and heat pump systems and is most accurate in areas with moderate climatic conditions.

On the contrary, the EER rating is mostly used for small window air conditioners and heat pumps and is ideal for comparing two separate systems due to its greater accuracy.

Knowing the EER rating is useful if you’re living in an area that has an arid, hot climate.

Related Article How To Convert SEER To EER

Other HVAC Conversions Explained


KW/ton is one of the most vital metrics used for measuring the energy-efficiency of your unit. This metric is commonly employed for commercial and industrial HVAC systems.

Keep in mind that lower KW/ton indicates higher efficiency.With that said, here’s an equation to convert SEER to KW/ton:

EER = 12 / KW/ton

KW/ton = 12/EER

We know that EER = 0.875 x SEER, so put this equation into the KW/ton formula, and you’ll get the converted value:

KW/ton = 12/ 0.875x SEER


The coefficient of performance, also known as COP, is another vital measurement system for your HVAC units’ energy performance.

To convert SEER to COP ratings, you can use the equation:

EER = 3.41 x COP

COP = EER / 3.41

Since EER = 0.875 x SEER, so put the formula to COP equation, and you’ll have your COP ratings:

COP = 0.875xSEER / 3.41

Related Article EER To COP Conversion Formula

People Also Ask (FAQ)

What is the best EER for an air conditioner?

Although higher ratings mean higher efficiency, nevertheless, the best energy efficiency rating for AC units is 12.

Does a higher SEER mean better cooling performance?

Yes, a unit with a higher SEER rating provides better and more efficient cooling, helping you save money on utility bills.

Does 16 SEER AC qualify for tax credit?

Yes, a 16 SEER mini-split air conditioner qualifies for the federal tax credit.

Does EER include fan energy?

Yes, the Energy Efficiency Rating (EER) does include fan energy.

What is more important, EER or SEER?

Both are important because of their functions. If you want to know your unit’s seasonal performance, the SEER rating is essential. However, if you want to know your unit’s energy efficiency at a specified time, the EER rating is necessary.


Air conditioners are effective heating and cooling systems, especially if they’re energy-efficient. Otherwise, the bill at the month’s end may be an unpleasant surprise.

Therefore, it’s essential to know your unit’s EER and SEER ratings; the higher the EER and SEER ratings, the more efficient energy-efficient it will be.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.