What is Energy Efficiency Rating for AC? EER Explained

energy efficiency score image

With summer in full swing, air conditioners and other electrical appliances are working overtime and consuming lots of energy.

How much energy? Buildings alone account for almost 70% of all greenhouse gas emissions in New York City. 

This has led to an increase in energy utility bills and a reliance on gas and other fossil fuels. So consumers understandably want to know: what are the most energy-efficient air conditioners? And how do you understand EER and SEER ratings?

As a World Leader in Sustainable Energy & Carbon Footprint Reduction, we’ve provided a detailed breakdown of everything you need to know about EERs, including what they are, how they’re calculated, why they matter…and why they aren’t the only (or best) solution for reducing energy consumption and costs.

What is EER?

An Energy Efficiency Rating (EER) is a rating system used to measure the energy efficiency of air conditioners. The EER is a measure of how much cooling a unit provides for every watt of electricity it consumes. The higher the EER, the more efficient the air conditioner.
Every air conditioner has a certain EER outlined in terms of values or numbers.

An air conditioner’s energy efficiency ratio is obtained by dividing its cooling capacity (measured in British Thermal Units, or BTU) by its energy consumption, measured in watt-hours.

In other words, it’s a measure of how efficiently an air conditioner uses electricity. The higher the EER rating, the more efficient the air conditioner and the lower your operating costs. 

Why should I care?

Although buyers consider the performance and aesthetics of the air conditioning systems when making purchases, not many know that the Energy Efficiency Rating is an essential factor. EER shows you exactly how energy efficient a unit is and how much money you can save on your energy bill. A unit with a high EER will cost less to operate than a unit with a low EER.

This is especially important for buildings in New York City looking to raise their Energy Efficiency Score. The NYC Building Energy Efficiency score is a way for the city to track a building’s energy usage and emissions over time. The goal of the energy grade is to help buildings save money on their energy bills and to reduce their environmental impact.

There are a few recent laws that have been passed that affect the NYC Building Energy Efficiency score. One of these is the Climate Mobilization Act, which requires all buildings over 25,000 square feet to reduce their greenhouse gas emissions by 40% by 2030 – and 80% by 2050 relative to 2005 levels.  

This Act will affect over 50,000 buildings, which is approximately 60% of NYC’s square footage.

A high EER unit will not only help reduce overall costs but can also help buildings avoid upcoming fines placed on buildings with energy usage over the legal limits. 

However, only having high EER AC units will not be enough to meet the lower energy expenditure requirements. 

The solution? Alternative Sustainability.

Alternative Sustainability (AS) is the only company that guarantees its products will reduce a building’s carbon footprint and raise the energy score above the 2030 penalty levels without using any fossil fuels.  

Yes – NO FOSSIL FUELS. With AS, building owners won’t have to worry about any LL97 penalties. We want to get fossil fuels out of buildings as much as possible. 

We’ve designed energy-producing devices that are changing the energy-production landscape, reducing carbon footprints, and helping buildings & homeowners lower utility costs.

Our Low Carbon PTAC units are the only ones on the market with: 

  • Quieter operation, especially in heat mode; super quiet 
  • Galvanized steel enclosures with electrostatic paint so there is no rusting
  • Sealed, self-lubricating fan motors 
  • Built-in heat sources

So, what does all that do for you?

  • Up to 80% in gas reduction in buildings
  • Overall energy reduction
  • An ROI of 3-5 years when figuring in building gas consumption reduction

We’ll go into more detail later. For now, let’s continue with our EER & SEER guide. 


Energy efficiency is important, but it’s not the only factor you should consider when buying a new air conditioner. Seasonal Energy Efficiency Ratio (SEER) is another measure of cooling efficiency. The objective of SEER is to capture more accurately the practical energy efficiency of air conditioners during the summer.

Although they are both essential factors to consider when purchasing an air conditioner, they have distinct purposes. EER measures the energy efficiency of your air conditioning unit at one particular temperature. It’s a more straightforward measure of how much energy the appliance uses to produce a specific amount of cooling. It is calculated at set indoor and outdoor temperatures and is a theoretical measurement of how efficient a unit is. 

SEER is more comprehensive: it measures an appliance’s energy efficiency over an entire cooling season and considers an appliance’s Energy Efficiency Rating at a range of temperatures, not just one set temperature. It has more practical applications because it measures the efficiency at actual temperatures. 

The Seasonal Energy Efficiency Rating is more extensive than the Energy Efficiency Rating because it allows you to see how much energy your air conditioner will use over an extended period and in different weather conditions. Also, the Energy Efficiency Rating mainly applies to room air conditioners. In contrast, the Seasonal Energy Efficiency Rating (SEER) is a rating that can be given to any cooling system, including central air conditioners.

This means that the Seasonal Energy Efficiency Rating (SEER) is an average of the AC’s energy efficiency, while the Energy Efficiency Ratio (EER) is one specific data point. Also, the EER and SEER are used at different times. EER is considered when the temperature of your location is 95°F or higher, while SEER ratings are used for locations with moderate climates.


What is a Good EER Rating for an AC Unit?

The first thing to know is that the higher an appliance’s Energy Efficiency Rating (EER), the more efficient it is. An air conditioner with a higher EER consumes less energy to provide the same amount of cooling as one with a lower EER. 

According to the U.S Department of Energy, the national appliances EER standard for a room air conditioner ranges above 8.0. The EER is 9.0 for users living in mild climates, while hot climates vary over 10. (Energy efficiency is especially important in hot climates, where air conditioners tend to run for long periods of time.)

Unfortunately, many air conditioning system producers fail to consider the environmental factors while manufacturing, bringing a one-size-fits-all appliance to the market.

How to Calculate EER Rating of an Air Conditioner

To calculate the Energy Efficiency Ratio for your air conditioner, you’ll need to know the cooling capacity in British Thermal Units per hour (BTUs/hr) and the power consumption in watts. The BTU rating should be available from the manufacturer’s documentation, and the power consumption can be found on the nameplate or EnergyGuide label.

The best formula for calculating the Energy Efficiency Rating (EER) is:

EER rating = Capacity (in BTU) / Power (in W)

For example, if you have an air conditioner with 9,500 BTU of cooling energy, and it takes 950 watts to power it, the EER is 10.

9,500 BTU / 950 w = 10 EER.

EER is calculated with a 95 °F outside temperature, an inside temperature of 80 °F, and 50% relative humidity.

EER ratings


Benefits of a High SEER/EER Air Conditioners

Using appliances with high Energy Efficiency Ratings (EERs) has several benefits. They include:

Significant Energy Savings

An essential benefit is that EER air conditioners help you save money on your energy bills. High Energy Efficiency Rating appliances use less energy to provide the same amount of cooling as their lower-rated counterparts, which means you will decrease your energy consumption and bills.

In some cases, the Energy Efficiency Rating of an appliance is so high that it can offset any increased unit cost over time. 

Still, there are alternatives that can save more energy – and further reduce cost – that we’ll cover below. 

Improved Cooling Comfort

In addition to saving money and helping the environment, high Energy Efficiency Rating appliances also provide improved cooling. These appliances cool your home more effectively, which means you can enjoy a comfortable temperature all day.

If you live in a hot climate, a high Energy Efficiency Rating air conditioner is essential for keeping your home cool and comfortable at lower costs. 

Financial Incentives

There are several government incentives and manufacturer rebates for purchasing high-efficiency air conditioning units. These rebates are often used to promote high-energy-efficient air conditioners and help users save money. 

Plus, reducing energy usage will help buildings apply to the new energy level laws being implemented in NYC and other cities across the world. But…not enough to avoid LL97 penalties. 

Lower Carbon Footprints

High Energy Efficiency Rating appliances also help to lower your carbon footprint. These appliances use less energy, which means that they produce fewer greenhouse gas emissions. 

If you are looking for ways to live a more sustainable lifestyle, high EER and SEER appliances are a good place to start. But, there are even more energy-efficient solutions for those looking to continue to reduce costs and save energy.  

Alternatives to High SEER/EER Air Conditioners

If you’re looking for alternatives to high SEER/EER Air Conditioners, you need to consider Alternative Sustainability. AS is a manufacturer of state-of-the-art, patented (and patent-pending), energy-producing devices. 

We design energy-producing devices that are changing the energy production picture and saving buildings & homeowners money, all while significantly reducing carbon gases. 

Let’s lose the fossil fuels, energy-draining heat coils, dirt build-up, and ridiculous energy costs. Low Carbon PTACs are the answer, especially for areas with cooler temperatures.

PTACs are air-cooled units, which means they use external air to cool their condensers (the part that does the real work), while the heat source is usually steam or hot water. But, that heat is always provided by gas – whether directly piped into the unit or whether the gas is used for large boilers that produce steam or hot water. 

The bottom line is gas is used for the supplemental heat source…but that’s what we’re out here to change.  

Alternative Sustainability’s Low Carbon PTAC offers the following advantages over standard PTACs: 

  • Built-in, very efficient heating elements. Not the typical Calrod or heating wire that most other manufacturers use.
  • Self-limiting heating coil conserves energy
  • Hydronic option for colder areas that need extra heat
  • Additional thermal and sound insulation (quiet – no hums, ticking, banging, or knocking from the typical steam heating coil.)
  • Self-lubricating motors mean they operate more efficiently and don’t burn out nearly as often as conventional fan motors.
  • Built-in heat source — no need for external steam, hot water, or gas
  • Built-in UV-C sterilization — later, 99% of bacteria and viruses!

Bottom line? We enhance the traditional PTAC in every way possible so there is less dependence on building plants, fewer energy costs, and better customization. 

We’re the only company that produces energy-producing devices that change the energy production picture, reduce CO2 gas, and help buildings & homeowners save money. And we can do this with an ROI of 3-5 years. 

We put our money where our mouths are, too. Other companies get away with a one-year warranty because they know that’s how long it’ll take before the things start rusting and falling apart. 

But with Alternative Sustainability, you’ll get two years of parts and labor – plus an additional four years for the compressor part. 

Our services are open to businesses and home or property owners who need to reduce their carbon footprint, increase their energy efficiency, invest more in clean energy, cut their gas, oil, or electric bills, make clean energy, and take advantage of government tax incentives. 

Choose Energy Efficiency with Alternative Sustainability 

There are no other products in the world that will help residential, commercial, or any other multi-unit building reduce their energy usage enough to meet the upcoming NYC building energy requirements. For example, the Climate Mobilization Act will require all buildings over 25,000 square feet to reduce their greenhouse gas emissions by 40% by 2030 – and 80% by 2050 relative to 2005 levels.  

Without Alternative Sustainability, it will be almost impossible to avoid the new fees and fines that will be placed on buildings with energy usage over the legal limits. Our heating and cooling solutions conserve energy, don’t break the bank, and save you thousands in energy costs on your residential, commercial, factory, and any other properties. 

We guarantee our products will reduce a building’s carbon footprint and raise the energy score to levels above the penalty levels, and help save the environment along the way.

Of course, we’re not only manufacturersーwe’re also energy consultants who can review your building and tell you exactly the changes you need to make to improve your energy consumption right now. 

It’s time to act: book a free consultation with us today.