EER to COP: Online Calculator for AC Units (+ COP to EER)

Did you know three-quarters of all American houses have air conditioning systems due to the changing climate? This usage is an immense strain on American pockets and the fight against global warming!

Having an efficient HVAC system negates both these worries. You will save a significant amount on your energy bills and keep your environment safe with low carbon footprints.

However, not all HVAC systems offer the same efficiency, which is why it’s essential to do your homework before purchasing. To determine efficiency levels, consider the COP and EER ratings.

If you’re planning to buy or upgrade your existing HVAC system, learn more about these COP and EER ratings. Read on as we help you get there:

Why Calculate And Monitor COP & EER

Calculate and Monitor COP & EER

COP (or Coefficient of Performance) shows the efficiency of heating/cooling units. It’s the ratio of heat dissipation and energy consumed.

Higher COP means the unit operates efficiently, while lower COP may have adverse effects on your unit’s operating cost.

Here’s the formula to measure COP:

COP = Q/W  

On the other hand, the EER rating of your cooling system is a ratio of cooling output and electricity consumed.

Typically, EER ratings are calculated using constant inside and outside temperatures such as 80°F and 95°F, respectively, and 50% humidity levels.

EER ratings are read similarly to COP: higher EER ratings indicate the system works more efficiently, while the lower suggests the opposite.The formula of EER rating is:

EER  = capacity (BTU) / Power (wattages)

How To Convert EER To COP (+ COP To EER)

Luckily, you can use three easy ways to convert EER to COP or vice versa:

Covert By Formula

Since COP or Coefficient of Performance is the metric used for energy performance of heating as well as cooling units, according to the first law of thermodynamics, it can be calculated using the equation:

COP = Q /W

Q represents the heat taken or provided to the unit, and W indicates work (or electricity).

Based on the COP definition, the EER rating equation can be deduced. Here’s how you can measure EER ratings from COP:

EER = 3.41 x COP

Use this formula to convert COP to EER, whereas if you want to convert EER to COP, the equation can be:

COP = EER/3.41

Chart conversion

In case you don’t want to do all the calculations to find out the COP value, you can use the EER to COP conversion chart, which is relatively simple to read.

Here’s the EER to COP conversion chart with few examples showing EER ratings and their equivalent COP values:

EER to COP Ratings

However, if you want to convert COP to EER ratings of your unit without doing all the maths, you can use the COP to EER conversion chart to make things a lot easier:

COP to EER Ratings

Online Calculator

The formula and conversion chart are not the only things you can use to calculate your HVAC system’s heating and cooling energy efficiency.

Apart from equation and chart, the online EER to COP or COP to EER conversion calculator can also prove useful in helping you pick out a heat pump or air conditioner.

Using the converter calculator is pretty simple: all you need to do is choose your existing metric from ERR to COP and input details – that’s it, you’ll have the EER as well as COP ratings instantly!

Understanding EER, SEER, And COP In HVAC

As is already apparent, the efficiency of your air conditioners and heat pumps is measured through SEER, EER, and COP ratings. Read on as define each separately:

The Energy Efficiency Ratio, or EER, is an energy-efficiency value used to identify cooling capacity (BTUs) in the given power (wattages). You can locate EER ratings within the condenser of your HVAC system.

EER ratings are essential for many reasons: you can save money on your utility bills, get improved cooling comfort, and reduced carbon footprints.

On the other hand, SEER ratings or Seasonal Energy Efficiency Ratio is employed mainly for central air conditioning and heat pump systems. It’s the ratio of your system’s cooling output against the power consumed over the entire season.

Like EER ratings, SEER ratings also help you ensure the better energy-efficiency of your unit. Once you learn to read these ratings and shop accordingly, you can get higher savings on energy bills and efficient operations cost.

Lastly, the COP ratings are used to assess the efficiency of your unit’s heating and cooling. It’s a ratio of output heating/cooling (in Wh) against energy used (in Wh). Like EER and SEER ratings, the COP ensures lower energy costs and higher power-savings.

Related Article What Does HVAC Stand For?

SEER Rating Chart

People Also Ask (FAQ)

Is a higher COP rating better?

Yes, a higher COP value (ratio) is better because it provides higher efficiency and low operating costs.

Can COPs be negative?

No, they can’t. Usually, COPs for heat pumps and refrigerators are greater than 1.

Can COP be less than 1?

Yes. The COP value of your air conditioner and refrigerators can be higher and less than 1. However, the COP ratio of heat pumps always remains higher than 1.

What is a good EER rating?

Normally, a 12 EER rating is considered a good rating. Nevertheless, higher EER ratings mean the unit is more efficient.

What is a good SEER rating?

Anything above 13 is considered a good SEER rating for your cooling or heating system. Anyway, like EER ratings, higher SEER ratings mean more efficiency and less power consumption.


For climates with mild cooling and heating needs, air conditioners and heat pumps are not stressful to keep. However, their efficiency varies from model to model. That’s why you need to check their COP and EER ratings to ensure higher efficiency and savings.

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.