US consumers can anticipate the yearly cost to cool their homes based on the SEER rating of an AC system. Typically, the higher its SEER score, the less someone must pay to keep their home cool. However, not everyone understands this scoring system or why it matters. Here is a quick breakdown of this AC performance rating metric, so you can be prepared while shopping.
Calculating an Air Conditioner’s Seasonal Energy Efficiency Ratio
First and foremost, a homeowner should learn how SEER scores are calculated. The seasonal energy efficiency ratio can be determined by dividing BTUs by watt-hours to derive the final figure. In essence, this creates a ratio of the cooling produced by the system and its energy consumption.
As the number increases, so does the system’s overall efficiency, so pay attention to it. Low scores indicate you will spend less using the system throughout the year, saving money over time.
Using a 10-SEER, 5,000-BTU AC system for 1,000 hours would require 500,000 watt-hours per year. Thus, paying $0.20 per kilowatt would mean you pay $0.10 per operating hour to keep the system turned on.
Comparing EER, SEER, and COP
A unit’s energy efficiency ratio or EER is correlated with its coefficient of performance or COP. Usually, industry analysts test units at 95 °F for the outside temperature and 80 °F, assuming a 50% relative humidity.
EERs use mixed units, whereas SEER units do not use them because it utilizes COP during calculations. Since COP has identical units for the numerator and denominator, they cancel out.
Theoretically, a system’s maximum SEER ratios are defined by the laws of thermodynamics. A 120-EER AC system may be created one day, but nothing higher than that will ever exist.
Government Mandated SEER Standards
Since the rating system entered mainstream use, it has become the defacto standard. Today, it even carries the legal weight of the law behind its back, thanks to Congress.
Beginning in 2006, a rating of 13 became required for commercially sold systems. Before that, systems had to score at least a 10, dating back to 1992. As a result, seeing systems with SEER scores below nine is relatively uncommon due to aging.
More recently, the US Department of Energy revised energy conservation rules. They imposed elevated requirements on residential HVAC systems and implemented regional standards. In the Southeastern US, they must now obtain a score of 14 SEER or higher.
Determining Your Annual Cost of Cooling
A typical US consumer determines energy consumption by using a simple-to-understand formula. Start by making your HVAC system’s cooling capacity and multiplying it by the current electrical modifier, which equals 0.132. Then, divide this sum by the SEER rating. Nowadays, an average system’s score ranges from 15 on the low end to 18 on the high side.
Higher-efficiency models may be found with ratings exceeding 20 in some instances. Nevertheless, the price tag may increase by $1,500 to $2,500 when comparing 15-SEER and 17-SEER systems. Despite the insubstantial efficiency gains, the purchase price can increase a ton.
Minimum Rating Required to Qualify for Federal Tax Credits
Efficiency improvements may be worthwhile after considering the federal tax benefits. To qualify, you must possess a SEER-16 system or higher, and the condenser and compressor must be housed separately. Fortunately, this is standard in modern residential applications, so it should be negligible.
Other Factors to Take Into Consideration When Upgrading HVAC Units
Several additional considerations everyone should keep in mind are a unit’s power production. Generally, this is expressed using British Thermal Units or BTUs. Without sufficient power, homes will remain hot, even with the AC cranked to the max.
Additionally, think about noise production, especially in dense neighborhoods. Some local municipalities have set restrictions, limiting noise levels. Furthermore, the system should be reliable, or you will pay out the nose for repairs.
Why Does an AC’s Rating Matter
Lower ratings mean it will cost more to cool your home, particularly whenever it is hot outside. Consequently, spending a little more to acquire a more efficient system may be worth it.