CleanAir Solutions Blog

Air Conditioning Terms You Need to Know

confusing air conditioning terms

BTU, anyone? SEER? EER? What do all these terms mean? And how can they translate into paying less (or more) for your energy bills each month?

For that matter, how does the type of air conditioner you choose factor into the overall cleanliness of your indoor air at home and at work? Can your air conditioner's health really affect your health?

In this post, learn about some of the most important air conditioning terms and what they mean for the purity of the air you breathe every day.

A Brief Glossary of A/C Terms

Unless you have purchased an air conditioning unit in the past, have worked in the cooling industry, or just have a passion for reading the dictionary, you (like most people) probably aren't sure what the following terms mean.

So here is a handy glossary to refer to when the need arises:


BTU is an acronym that stands for “British thermal units.” A thermal unit is “the amount of work required to raise the temperature of a single pound of water by one degree Fahrenheit.”

What does this have to do with air conditioners? In the world of cooling, BTUs are an indication of each air conditioner's ability to cool a space by removing the heat in that space. Each air conditioner comes with a BTU indication that lets you know if it is the right size for the space you are trying to cool.

For example, according to Energy Star, you would need an A/C unit with a 5,000 BTU capacity if you wanted to cool a room up to 150 square feet. But if you have a 2,500-square-foot house to cool, you would need to choose an A/C unit with a 34,000 BTU capacity.

Some consumers, in a well-intentioned attempt to improve cooling efficiency, will choose an air conditioner that is rated at a higher BTU than the size their space actually requires. Unfortunately, this will not provide any savings and can actually be harmful in terms of air humidity and purity.

If you install an A/C unit rated at a lower BTU than what your space needs, it will never stop running, and you will end up spending more on your energy bills, but will never feel like your home is cool enough.

Conversely, if you install an A/C unit rated at a higher BTU than what your space needs, it will shut off sooner than it should and you will have an uncomfortable amount of humidity in your indoor air, which can lead to the growth of mould spores and mildew.


The acronym EER stands for "energy efficiency rating." This rating corresponds to how much cooling you can reap from each unit of electrical energy. Typically, a unit with an EER rating (instead of a SEER rating — read on for more) is a smaller window or wall air conditioner rather than a central unit.

Not all air conditioners are created equally when it comes to EERs. The higher the EER rating, the less electrical energy input is required to cool a space. However, often units with a higher EER rating also have a higher sticker price.

So here, you want to consider your overall energy costs as well as the percentage of time each year when you really need to run your air conditioning, in order to determine if the higher sticker price will pay off (and if so, over how many years' time) in terms of overall electrical energy savings.

In general terms, any A/C unit with an EER rating of 10 or higher is considered very energy efficient.


This similar acronym stands for "seasonal energy efficiency rating." SEER is the rating used most frequently to indicate energy usage per cooling output for central air conditioning systems.

In the same way that a higher SEER-rated A/C unit will cost less in terms of energy use to operate, it may also be higher priced at the time of purchase than its lower-rated peers. So it may take some calculation to determine whether opting for a higher rating will pay off over the long term in energy savings.

Generally speaking, any air conditioning unit with a SEER rating of 13 or higher is considered very energy efficient.

Energy Star

Energy Star certification is currently the gold standard for energy efficiency across a range of appliances, including but not limited to air conditioning units.

An air conditioning unit of any size that carries the Energy Star seal of certification will consume up to 10 percent less electrical energy and save you up to 20 percent on your energy bill.

Purify Your Indoor Air with the Right A/C Unit

Buying a new air conditioner can be a daunting task, especially with all these new terms to learn. But the payoff is worth the work, especially when you have clean, pure indoor air to breathe and a low energy bill to show for it.

By using the BTU rating to match your space size to the right-sized air conditioner and selecting a suitably high EER/SEER and/or Energy Star rating to maximize the electricity you use, you will be doing your part to ease the planet's burden as well as your own.

Contact Clean Air Solutions Hamilton for Help

Here at Clean Air Solutions Hamilton, we are proud resellers of the Napoleon SEER air conditioning units.

These highly rated, energy-efficient air conditioning units deliver maximum energy efficiency for your space and budget and come with a 10-year limited warranty (compressor and parts). For clean, pure air with just the right balance of humidity, Napoleon central and side discharge air conditioning units always deliver the highest level of reliability and efficiency.

For a free estimate and help selecting the right A/C unit for your space and cooling needs, contact us at 905-544-2470 or online at

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