Getting a new air conditioning unit and looking at different air conditioners? You probably already know that a higher SEER air conditioner is more efficient.
But by how much? And is the difference worth it in the Phoenix Area?
Good questions. In this article, we’ll show you how to estimate the energy savings between any 2 air conditioners with different SEER ratings (assuming all else is equal).
And, for example purposes, we’ll be using 3-ton, 16-SEER vs 14-SEER air conditioners because they are popular sizes and choices in the Phoenix area.
So let’s get started...
Psst...our AC techs do all this math for you during one of our FREE AC installation estimates. Just contact us with your SEER questions.
Determine each air conditioner’s estimated annual energy use with this equation:
[(Size of AC system x 12,000) / SEER] x 2100 = amount of Watt-hours used annually
To better understand what’s happening here, let’s breakdown each step of this equation:
The first part of the equation is calculating the amount of cooling your air conditioner provides. 1 ton of cooling = 12,000 BTUs. (There’s a lot of history here if you’re curious).
This is the capacity of your AC system, much the same way the horsepower of a car tells you the capacity of the engine.
Next, we need to calculate how efficiently your AC system provides that capacity...
Dividing the capacity by the air conditioner’s SEER gives you the approximate number of Watts the air conditioner uses per hour.
You’ll now have the amount of energy your AC uses per hour, which is similar to how the MPG of your car tells you how many miles you can go on one gallon of gas.
Now we simply multiply by the number of hours you’ll use your AC...
According to Energy.gov’s calculator the average Phoenix-area home uses their air conditioner for about 2100 hours per year.
Which gives you...
You’ll now have the estimated amount of energy (measured in Watt-hours) that the AC will use in a year.
So for our 3-ton example air conditioners, we get:
For a 14-SEER:
[(3x12,000)/14]x2100=5,400,000 Watt-hours (rounded to nearest thousand)
For a 16-SEER:
Now that we know approximately how much energy each of our air conditioners will use, we need to find the difference between them. This is simple subtraction:
Energy use of 14-SEER
- Energy use of 16-SEER
= Energy savings of higher unit
In our example, the difference is 675,000 Watt-hours, annually.
Now we simply need to calculate the actual amount of money this number equates to. Your electric company (either APS or SRP) charges you per kWh, or kilowatt-hour.
To convert the Watt-hours to kWh, you divide by 1000.
So our example is 675,000 Watts/hour / 1000 = 675 kWh.
Now to get the estimated annual energy savings, you just multiply by the rate your utility company charges. The average electrical rate in the Phoenix area is around 12 cents per kWh.
So a 3-ton, 16-SEER unit in Phoenix saves you about $81/year (675 x $0.12) in electricity costs over a 14-SEER unit.
Well, it will depend on 2 things:
So, if in our example the 16-SEER air conditioner was going to cost $900 more and you only planned on being in your home 5 more years, you likely won’t see the payoff ($81 x 5 years = $405).
But if you plan on living in your home for the full 15 years of the air conditioner’s life, you will see some overall savings ($81 x 15 = $1215).
And don’t forget: when calculating the difference between the 2 systems, a 16-SEER+ air conditioner can qualify for the $300 energy efficient tax credit.