a lamp which represents energy
Articles,  Clean economy

What is EER and how is it calculated?

Something that many people fail to consider when heating, or cooling, their home or place of work is the EER of the devices they intend to use.

This is largely because most people haven’t heard of EER to start with!


What is EER?

EER is an acronym for “Energy Efficiency Ratio“. This simply means how energy efficient a particular heating or cooling device is.

Efficiency is highly important when selecting a heating or cooling device
because it’s the best way to gauge how much it is going to cost you in real terms. Having a huge AC unit that is capable of keeping your office at a cool, comfy, temperature is all well and good, until you check your bills
next time around.

energy efficiency ratings from A to G

How is EER calculated?

Luckily, the EER calculation for a heating or cooling device is pretty easy to work out so you won’t be flying blind even if a device doesn’t clearly display its EER for you to see.

The calculation is heat output divided by the power input. This may sound confusing when you are considering the EER of a cooling device, but that’s
not a problem. All devices measure heat output using units called BTUs which stands for “British Thermal Unit” , though you will rarely see it written in this way. 


picture explains how to calculate EER

To help you better understand how EER is calculated, here is a sample calculation:

EER = Heat Output / Power Input.
Heat Output is displayed in BTU
Power Input is displayed in Watts
If we were to apply this calculation to a real device we might see

something like this:

Example Air-conditioning unit EER = 25000 BTU / 2500 Watts 

EER =10

How do I apply the EER rating to my situation?

Now we understand what an EER is, and even how to calculate it ourselves if we are in a pinch, it’s important to understand how to use this information.

When comparing heating or cooling units and their EER we are looking for the highest rating. The higher the rating, the higher the efficiency.

If we had two standard window air-conditioning units with two different energy efficiency ratings, in this example let’s say

they are rated 10 and 11, you would want to pick the one rated 11 because this unit would be 10% more efficient.

than its counterpart which would ultimately lead to saving you 10% on your electricity bill at the end of the month (in theory).

The benefits of energy efficiency for the planet and environment

A better EER rating is directly linked to having a far more friendly carbon footprint. Being conscientious of energy efficiency is one of the best steps we can take as individuals to make the planet a better place.
Reducing our power consumption leads to fewer trees cut down, less oil burnt, and fewer habitats being disrupted.

One or two people going out of their way to purchase heating or cooling units with great energy efficiency ratings isn’t going to stop the rainforest from being cut down. But, if we all do our part, maybe we can make a real difference.

Whether that be reducing your energy consumption at home or doing your best to
improve the energy efficiency rating of your workplace – every little bit helps!

a bright lamp in hand

In summary

EER is a great way of comparing the efficiency and therefore cost-effectiveness of two or more devices. But, it is not always enough on its own to make an informed decision. EER is best used as a supplementary factor and a good EER rating will save you money and help the planet along the way.