A/C SEER Rating

When an HVAC unit works efficiently, it will consume less energy as it makes your home feel comfortable. A factor that helps you determine an air conditioner’s efficiency is its Seasonal Energy Efficiency Ratio (SEER) rating. An A/C’s SEER rating relates to how much energy and money the unit will use during operation over the course of a year. Understanding what this rating means for you before an A/C installation will help you make an informed decision about the cooling unit that best meets your needs.

How to Calculate SEER Ratings

SEER ratings are ratios derived by calculating the annual cooling output during the cooling season divided by the total electric energy input. The total cooling output is the A/C’s British thermal unit per hour (BTU/h) multiplied by the number of cooling hours per day and the number of cooling days per year. For example:

6,000 BTU/h x 10 cooling hours per day x 200 days per year = 12,000,000 BTUs per year

Using the example above, if an air conditioner has a SEER rating of 15 BTU per watt-hour (Wh), you could calculate the estimated annual energy use as follows:

12,000,000 BTUs per year ÷ 15 BTU/Wh = 800,000 Wh per year

To calculate the annual average power use, divide the A/C’s BTU/h by the SEER rating. For example:

6,000 BTU/h ÷ 15 SEER = 400 watts (or 0.4 kilowatts)

To calculate the cost of electricity when using the A/C, multiply the average kilowatts from the formula above by your local electricity rate in kilowatts per hour (kWh). For instance, 0.4 kW x $0.25 kWh = $0.10 per hour. The EnergyGuide (Yellow Sticker) label on the HVAC unit will also indicate the amount of energy the equipment consumes.

What Is a Good SEER Rating?

The US Department of Energy sets the minimum SEER rating by region. Currently, the minimum SEER for air conditioners is 13 or 14 depending on where you live. The good news is that many modern units have ratings between 13 and 21. When looking at the SEER rating, you may be wondering if an A/C unit with a high SEER ratio is worth it. Higher SEER units prove better cooling power and lead to more comfortable spaces. These units also offer more consistent cooling and don’t require your A/C to frequently turn on and off to maintain temperatures. If you want to replace a 20-year-old air conditioner with a new one that has the minimum SEER rating, there’s a good chance that your energy efficiency will improve instantly. In general, good SEER values for residential air conditioners are 14 to 16.

How SEER Ratings Affect Your A/C Unit

Before an A/C installation, keep in mind that a SEER ratio indicates the unit’s maximum potential. This means that when a unit states that it has a value of 21 SEER, for example, the rating can be as high as 21 SEER. It will not always perform at 21 SEER because of other variables such as outdoor temperatures, thermostat settings, building envelope and current ductwork.

SEER ratings are variable, which means that HVAC units with the highest SEER values may not save you money in the future or “pay for themselves.” If equipment rated at 21 SEER performs at an average of 15 SEER, it may be wiser to save money and purchase an A/C with a lower SEER rating. An HVAC specialist can help you determine the most appropriate SEER rating for your new A/C unit using special equations that average the maximum Energy Efficiency Raito (EER) over the range of expected seasonal temperatures. In general, good SEER values for residential air conditioners are 14 to 20.

Other Factors to Consider in an A/C Unit

While SEER ratings are an important factor when buying an air conditioner, it is also necessary to consider:

  • Your budget
  • The size of your home
  • The size of the air conditioning unit and its air handling capacity
  • EER ratings
  • Ease of maintenance
  • Lifetime costs, including energy, maintenance, and repairs
  • A unit’s quality and life expectancy
  • The manufacturer’s history of reliability
  • Warranty terms

The implementation of SEER ratings has made air conditioners more energy efficient and Earth-friendly, creating a win-win situation for all. When planning a new A/C installation, contact your Honeywell HVAC specialists to learn more about the options available and receive expert help with determining the best SEER rating for your comfort and energy savings goals.