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What is EER Rating in Aircon Units?


Every cooling system has a rating procedure called Energy Efficiency Ratio (EER), which you may have noticed if you install a new HVAC system. Any specification sheet for different air conditioners will include them.

But did you know that the EER rating plays a crucial role in saving your expenses for electricity bills? This rating system helps users determine whether their air conditioning system signals energy efficiency.

To learn more about the energy efficiency rating system and the importance of EER rating in aircon units, continue reading this article.

Why Does EER Matter?

Most of the electricity used at home is consumed by an air conditioner. Your electricity bill is more impacted by how much energy our unit uses. Therefore, you should consider a system with electrical energy efficiency as a key deciding element while searching for a new air conditioner.

If you want to save money and receive lower energy bills, you should consider an air conditioner that offers a comfortable and cool atmosphere while consuming less electrical energy.

The Energy Efficiency Rating determines a system’s energy efficiency. It is one of the standard system performance ratings used in the HVAC industry to determine, quantify, and express an air conditioner’s power efficiency.

Understanding EER means it will enable you to correctly compare air conditioning systems in terms of their capacity for power-saving and helps you avoid choosing a less efficient system. A more energy-efficient unit can drastically cut your energy consumption.

As a result, knowing about EER before making an air conditioner purchase will make you a wise consumer who understands the long-term financial advantages that come with picking more energy-efficient equipment.

What Is the Difference Between SEER and EER?

Seasonal Energy Efficiency Ratio, also known as SEER, is similar to EER in that it is a ratio of cooling output to power intake, but the main difference is that the SEER rating is calculated throughout the entire summer season.

Room air conditioners often have EER ratings, while a large unit of central air conditioners uses a Seasonal Energy Efficiency Ratio (SEER) rating. Compared to EER, which measures energy efficiency during the warmest part of the year, SEER rating is more of an average EER.

We calculate the SEER rating using an inside temperature that remains constant throughout the season, while the outdoor temperatures can range from 60 °F to 100 °F. SEER rating guarantees that the efficiency rating is averaged out throughout the season.

On the other hand, the EER of an AC unit is calculated at a fixed indoor and outside temperature. Therefore, rather than providing an extensive overview of energy savings over a longer period, the EER provides more of a fast snapshot of the air conditioner’s energy savings.

EER is estimated with an outside temperature of 95 °F and an indoor temperature of 80 °F with a relative humidity of 50%.

How Do You Calculate the Energy Efficiency Ratio Rating of an Air Conditioner?

The EER rating is quite simple to calculate. You only need to be familiar with two practical metrics:

  • The capacity of an air conditioner. E.g: 6,000 BTU, 10,000 BTU, 12,000 BTU, 18,000 BTU.
  • Power of an air conditioner. E.g: 800W, 1,000W, 1,200W, 1,400W

What Is the EER Formula?

The EER rating for an air conditioner is calculated by dividing the cooling capacity (in British thermal units or Btu) by the power input in watt-hours. In other words, its BTU rating over its wattage is written as follows in a formula:

EER Rating = Cooling Capacity (BTU) / Power (in Watts)

The EER rating reveals how energy-saving an HVAC unit is. If the AC units are not costing much in your utility bills, then they might have a high EER.

Following the formula, the energy efficiency ratio (EER) is calculated by dividing the cooling capacity of the air conditioning unit by its power wattage.

Assume you have a 12,000 BTU mini split air conditioner with a 1000W power supply. The EER rating can be determined as follows. EER rating: 12,000 BTU / 1000 W = 12.

Essentially, a higher EER rating indicates that the system is more power efficient. It makes sense that choosing a new air conditioning system with a greater rating would be preferable. An air conditioner’s side will have a yellow sticker with the words “Energy Guide” written on it that displays the EER rating.

It is critical to comprehend that EER relies on an established set of conditions, particularly:

  • Outdoor temperature: 95F
  • Indoor temperature: 80F
  • Relative humidity: 50%

What Does 10.4 EER Mean?

Since we already have the energy efficiency ratio (EER) formula, here’s a sample calculation of an EER rating of 10.4.

Let’s say a portable 13,000-BTU AC unit uses 1,250 watts. It will have a 10.4 EER rating as a result. It’s expressed as a formula:

13,000 BTU / 1,250 W = 10.4 EER Rating

That sample calculation is based on running the air conditioner at an outside temperature of 95°F. The EER rating reveals an HVAC system’s electricity input efficiency.

Based on the rating chart, an EER 10.4 unit is 24% more efficient than a lower EER unit. In comparison, it will be 24% less cost to run an EER 11 portable air conditioner.

What Does 12.5 EER Mean?

Here is another sample calculation for the EER rating, but now, we will use a higher EER rate.

If you have a 24,000 BTU air conditioning unit with a 1,920 watts cooling capacity, the energy efficiency ratio (EER) rating would be 12.5. The formula is as follows:

24,000 BTU / 1,920 W = 12.5 EER Rating

An EER rating of 12.5 tells us that for every 1.9W of energy we provide to the air conditioner, the air conditioner will give us 24 BTU of cooling effect.

A 12.5 EER rating is an excellent one for an air conditioner. The most advanced devices can even achieve a high EER of more than 12.5 EER.

What Is a Good EER for Air Conditioners?

There are a lot of energy-saving air conditioners available in the market. But to save money on your power bill, checking their rating is the most suitable way to determine which AC is a good choice.

The average EER rating of an air conditioner is around 8.5. Thus, buying those with below 8.5 ratings is not recommended, while those with above-average 8.5 ratings are the most prudent decision from an efficiency standpoint. Considerably, an air conditioner with an EER rating of 11.2 is the most energy-efficient.

As new technologies become available, air conditioners will inevitably move toward higher efficiency ratings, resulting in greater comfort and convenience.

What Are the Benefits of Energy-Efficient Air Conditioners?

Now that you are familiar with EER and SEER ratings, allow us to go over some advantages and benefits that high EER and SEER air conditioners offer:

Significant Energy Cost Savings

Higher ratings directly translate to lower electricity consumption. As a result, lower utility bills mean more savings. For example, the higher the SEER rating of your air conditioner, the more energy efficient it will be.

Improved Cooling Comfort

In general, an AC with higher ratings utilizes more advanced technology. It would improve the features and cooling output of the air conditioner. As a result, you’re not just reducing costs but also getting improved cooling.

Minimized Lifecycle Cost

Higher AC energy efficiency ratio ratings have a higher upfront cost. However, lower operating expenses throughout the AC’s lifespan will eventually offset this. Besides, a newer, higher-efficiency AC would use advanced technologies and be less likely to experience serious problems.

Reduced Carbon Footprint

A more efficient system will be more ecologically friendly and will be your constructive contribution to the environment. In the current climate, we must all do our share to safeguard the environment and reduce our power consumption.

Final Thoughts

We know how crucial it is to monitor your power consumption wisely since utility cost comprises a sizable portion of your household’s expenses today, but that doesn’t mean you have to give up your comfort.

We hope this article helped you switch to a more economical cooling system and understand the EER rating in aircon units.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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