If you’re looking for a new air conditioning system for your Salida, CA, home, you likely want the most efficient model you can afford. If you’re unaware, ACs use a system called SEER that describes their energy efficiency. One of the purposes of the SEER system is to provide a simple way to compare the efficiencies of different ACs. At a basic level, using the system isn’t difficult. In short, the higher the SEER rating, the more efficient the AC. Unfortunately, that doesn’t tell you much about what to expect regarding real-world use. To help, here’s a detailed explanation of the SEER rating system and how best to use it in your purchase decision.
What Is SEER?
SEER stands for seasonal energy efficiency ratio. It’s an efficiency measure designed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). It debuted in 1975 alongside the Federal Energy Policy and Conservation Act of 1975 (EPCA). The system’s original purpose was to provide a way for regulators to set minimum efficiency standards for ACs.
Initially, the EPCA only specified suggested minimum AC efficiency standards based on the SEER system. It wasn’t until 1992 that the first enforceable minimum efficiency standards went into effect. As of then, the lowest-efficiency AC you could purchase had a SEER rating of 10. Today, in California and in southern states, the minimum SEER rating for a new AC is 15, while in northern states, the minimum is 14.
How Are SEER Ratings Calculated?
To assign a SEER rating to an AC system, manufacturers begin with another efficiency measure called EER. That stands for energy efficiency ratio, and it’s the result of a simple formula. To calculate it, you divide the AC’s maximum hourly cooling output in BTUs by its wattage. EER lets you know how much energy an AC uses per hour while operating nonstop for an hour.
The trouble with EER is that it doesn’t reflect real-world AC operating conditions. When you use the AC in your home, it won’t operate nonstop. It will cycle on and off to maintain your desired indoor temperature. It’s that real-world use pattern that SEER attempts to simulate.
SEER begins by assuming a range of outdoor temperatures from 65 degrees to 104 degrees Fahrenheit, averaging around 82 degrees. This assumption informs the rest of the formula, which simulates how often your AC cycles on and off. The formula does that by applying the system’s EER as follows:
- 100% EER for 1% of cooling season
- 75% EER for 42% of cooling season
- 50% EER for 45% of cooling season
- 25% EER for 12% of cooling season
It’s important to note that the result of the above formula may bear little resemblance to how you use your home’s AC. Average Salida summer temperatures can be significantly higher than those assumed in the SEER formula. However, all that means is you probably can’t trust the estimated operating cost listed on an AC’s EnergyGuide label. However, you can still use SEER ratings to gauge one AC’s efficiency relative to another.
Using SEER Ratings in Your Purchase Decision
You can use SEER ratings to compare the efficiency of ACs just by looking at the ratings themselves. But as you do so, there’s something important to remember. SEER ratings are not linear. The further you go up the SEER scale, the smaller the efficiency boost. In other words, the efficiency difference between a SEER 15 and a SEER 16 AC is bigger than between a SEER 16 and SEER 17 AC. That can make it hard to judge whether a higher-SEER AC is worth its price premium.
The good news is that a formula can tell you the exact efficiency difference between two SEER ratings. To use it, first divide the higher SEER rating by the lower one. Then, subtract one from the result. That should leave you with a decimal value. If you multiply that decimal by 100, the result is the efficiency difference between the two ACs as a percentage.
You can also use an AC SEER rating to determine how much a given AC costs to operate each hour. To do that, you divide the system’s BTU output by its SEER rating. The answer you get is how many watts of electricity the AC uses per hour. Dividing that number by 1,000 will convert it to kilowatt hours (kWh). Then, consult your electricity bill to see what you pay per kWh. Multiply the two figures to determine the AC’s hourly operating cost in your home.
A Word on SEER and SEER2
When you shop for an AC, you may notice that today’s models have both a SEER and a SEER2 rating. SEER2 is an updated version of the original SEER rating system. It includes stricter testing standards and factors in a broader range of outdoor temperatures. The testing also includes using more realistic ductwork static pressures to account for air resistance found inside the average home. As a result, SEER2 ratings should offer a more accurate representation of real-world system performance.
The first thing you’ll notice about SEER2 ratings is that they’re lower than corresponding SEER ratings. As a result, the minimum legally allowable SEER2 of a new AC is 14.3 in California and southern states. Also, there’s a way to convert between the two rating systems for easier comparison. If you multiply a SEER2 rating by 1.05, you get its equivalent SEER. It’s important to know that the result of the formula isn’t precise, however. So, you should only use it for rough comparisons and not to calculate actual operating costs.
What SEER Is Worth Paying For?
Generally speaking, it’s wise to buy a new AC with the highest SEER rating you can afford. However, you’re unlikely to recoup the price premium you’ll pay beyond a certain efficiency level. If you want to figure out if you will, you can estimate the operating costs of two ACs using the formulas described above. Then, add up your potential savings, assuming your new AC will last about 15 years. If your estimated savings exceed the price difference between the two ACs, it’s worth the extra upfront cost. Operating cost savings aren’t the only reason you may want a more efficient AC. After all, lower energy consumption equals a smaller carbon footprint. You’ll be helping the environment by buying a central air conditioner with a higher SEER rating, even if the lower operating costs do not justify the increased purchase price.
Your Local Efficient Cooling Experts
Since 2009, Loves Air has sold and installed quality, efficient ACs throughout Salida and the surrounding areas. We carry the latest AC systems from reputable manufacturers like Rheem and Bosch. As a locally owned business, we also focus on developing long-term customer relationships. This focus means you can count on us for quality AC installation at a fair price. If you need help with financing, we can help there too. Contact us today to schedule an appointment with one of our knowledgeable team members.
