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Thankfully, this one is easy. A 16 SEER air conditioner is far superior to a 10 SEER unit. Indeed, according to the Department of Energy, anyone shopping for an air conditioner today should consider models rated at least 13 SEER. Anything below 10 SEER is considered inefficient.

You will also notice that nearly all modern air conditioners are rated 13 SEER or higher. Be careful not to confuse SEER with EER or CEER. The latter two have much lower values than SEER.

Thus, a 10 EER air conditioner is considered highly energy-efficient. The same applies to 10 CEER values. However, 10 doesn’t even exist in modern appliances for SEER ratings because it’s an abysmal rating.

You’re probably wondering how bad is 10 SEER that it’s no longer acceptable. Let’s find out. We also explain the difference between a 10 SEER and 16 SEER air conditioner in detail to help you make an informed decision.

## What is SEER?

The Seasonal Energy Efficiency Ratio or SEER rating is a measure of the energy efficiency of air conditioners. It’s used alongside the Energy Efficiency Ratio (EER) and Combined Energy Efficiency Ratio (CEER) to indicate the level of efficiency among air conditioners. In Europe, they call it European SEER, i.e., ESEER.

The official definition of SEER is – the total cooling output of an air conditioning appliance during a typical cooling season divided by the total electric energy input over the same period. The higher the SEER value, the more energy-efficient the air conditioner.

## Calculating SEER Values

From the definition, it’s easy to calculate the SEER rating of your air conditioner, though most manufacturers usually indicate the value on the product label.

SEER = Total cooling output per season ÷ The Appliance’s total electricity consumption over the same period.

The BTU rating determines total cooling output. The BTU rating of an air conditioner is defined as the amount of heat (in British Thermal Units) the AC removes per hour. Thus to determine the cooling output per season, you need to multiply the appliance’s BTU rating by the length of the cooling season. The average length of the cooling season in the US is 1,000 hours, i.e., eight hours per day for 125 days.

## Minimum and Maximum SEER Values

The maximum and minimum SEER values are hard to define. For instance, there aren’t many air conditioners in the market rated under 9.0 SEER. 9.0 and 10 are the lowest ratings ever made available to consumers.

On the other end, SEER ratings can be as high as 30. Indeed, the refrigeration system with the highest SEER rating is known as the Carnot cycle. The Carnot cycle has an EER of 120 and a COP of 36. Since COP values are closest to SEER values, we can safely assume that the maximum SEER value is 36. But, of course, the Carnot cycle isn’t practical in real life. It only happens in the lab.

Of note, though, is that the US government controls appliance efficiency as part of its efforts to conserve the environment. And this is where it gets interesting.

- In 1987 legislation that took effect in 1992, the government passed legislation requiring a minimum of 10 SEER for all refrigeration appliances, including air conditioners. This is partly why there aren’t 9.0 SEER or lower air conditioners around. Of course, the other reason is that 9.0 SEER or lower ACs are dangerously inefficient.
- In 2006, the government revised the energy efficiency requirements with new legislation requiring a minimum of 13 SEER for all refrigeration appliances. The legislation required that all residential refrigeration systems developed after 2005, except window air conditioners, must have a SEER rating of 13. To quality for Energy Star Certification, the system must be at least 14.5 SEER. Window air conditioners were allowed to operate under the 1987 legislation.
- Finally, in 2015, the government revised the requirements again. This came when the extremely efficient mini-split systems entered the market. So, starting January 2015, all Southern States (totaling 15) must have mini-split air conditioners rated at least 14 SEER and 12.2 EER. Meanwhile, the rest of the country is allowed to operate under the 2006 legislation.

## Comparing 10 SEER vs. 16 SEER Air Conditioners

Now that we know a few things about SEER values, we can compare the performance of a 10 SEER air conditioner vs. a 16 SEER unit. This time, we’ll assume you’re shopping for a 22,000 BTU air conditioner.

**Electricity consumption **

Let’s begin with how much electricity each air conditioner would consume per hour, day, and over a cooling season.

An easy way to calculate the amount of electricity an AC consumer per hour is to divide the BTU rating by the SEER rating. Thus;

The 10 SEER AC would consume 22,000 BTUs ÷ 10 = 2,200 watts/hour. Since 1,000 watts = 1kw, the AC would draw 2.2 kilowatts/hour. This comes to;

- 2.2 x 8 = 17.6kw/day
- 17.6 x 125 = 2,200kw/year

Meanwhile, the 16 SEER air conditioner would consume 22,000 ÷ 16 = 1,375 watts/hour. This translates to 1.375kw/hour. This is equal to;

- 1.375kw/hour x 8 = 11kw/day
- 11kw/day x 125 = 1,375 kw/year

So, that’s a difference of 6.6kw/day or 825 kilowatts per cooling season. i.e., you’d consume 825 kilowatts more if you pick the 10 SEER AC over the 16 SEER AC.

**Running Costs **

We all love to think of purchases with cost savings in mind. So, how much more would you spend or save when you choose a 10 SEER AC over a 16 SEER model or vice versa?

It’s easy to calculate. But, first, we need to determine the cost of electricity. Currently, the price of electricity in the US is 13.76 cents (or $0.1376) per kilowatt-hour.

So, starting with the 10 SEER air conditioner, the cost of running the appliance would be as follows;

- Cost to run it per hour = $0.1376/kwh x 2.2 kwh = $0.3027/hour
- Cost to run it per day = $0.3027/hour x 8 days = $2.4217/day
- Cost to run it per season = $2.4217/day x 125 days = $302.72/year

Onto the 16 SEER air conditioner, the cost to run it per hour, day, and over an entire cooling season would be as follows;

- Cost to run it per hour = $0.1376/kwh x 1.375kw = $0.1892/hour
- Cost to run it per day = $0.1892/hour x 8 hours = $1.5136/day
- Cost to run it per season = $1.5136/day x 125 days = $189.2/year

So, what’s the difference in running costs? A massive $0.11/hour, $0.91/day, and $113.5/year. Yes, you would spend $113.5 more if you opt for the 10 SEER air conditioner! The other way to look at it is that you’d save $113.5 by opting for the 16 SEER air conditioner.

## Verdict

There’s no contest here. A 10 SEER air conditioner is dangerously inefficient, consuming 825 kW more per season to run compared to a 16 SEER model, assuming you’re shopping for a 22,000 BTU air conditioner. The difference is even more significant for larger-size air conditioners.

This can translate to hundreds of dollars in extra electricity costs. In our example, you’d end up spending at least $113.5 more, translating to $1,135 over ten years. Imagine what you could do with $1,135 right now!