How To Better Understand Heating And Cooling Equipment Energy Efficiency Ratings

Original posting by George Davis 9/6/16

What do they mean and how can they help me?

When you’re in the process of purchasing a new air conditioning, heat pump or other heating system, you will see a big yellow sticker on the unit, telling you the efficiency rating of that specific system. These efficiency ratings play a vital role in determining how much the system costs to both purchase and operate.

In general, system performance is measured by a higher seasonal energy efficiency ratio (SEER) and energy efficiency ratio (EER). Higher ratings mean lower operating costs, but they also mean higher upfront costs.

If you’re in the market for a new air conditioner, we believe it’s worth investigating higher-rated systems. Similarly, a higher rated Heating Seasonal Performance Factor (HSPF) means a more efficient air-source heat pump.

What does SEER mean?


SEER (Seasonal Energy Efficiency Rating) shows the electrical input required to run the air conditioning over one average cooling season, compared to how much cooling the system generates. This rating is assigned based on an average, lower temperature of 82 degrees. You should know that a 16-SEER A/C unit achieves this rating within this temperature range but not at higher temperatures.

What does EER mean?

EER, (Energy Efficiency Ratio) on the other hand, is more like calculating the “highway miles” of the system, as it is tested based on higher operating temperatures, generally 95 degrees or higher. This rating also takes into account humidity removal and is useful because it shows how an air conditioner performs under maximum cooling load.

Knowing how to navigate both efficiency designations is helpful during the buying process because many homeowners need to install an air conditioning unit that functions efficiently in both conditions: mild, warm days, and hot, humid days.

You shouldn’t sacrifice one rating for the other, and it’s important to keep in mind that an A/C unit with a high SEER rating won’t necessarily also have a high EER rating. Look at both ratings to make a wise purchase.

What does HSPF mean?

The HSPF (heating seasonal performance factor), like SEER, measures efficiency over the course of one entire season as a ratio of heat generated to electricity consumed.

In the United States, split-system heat pumps manufactured in 2015 or later must have an HSPF of at least 8.2, and single package units must have an HSPF of at least 8. The maximum possible HSPF for today’s most efficient heat pumps is 10.

What’s more important: SEER or EER?

EER measures a snapshot of a moment in time, whereas SEER measures usage over time. Therefore, HVAC experts say SEER represents a more important number to pay attention to for long-term energy usage. “I always concentrate more on SEER than EER,” says Dan Rich, Service Manager for ServiceMark Heating, Cooling & Plumbing’s King of Prussia office. “We’re always available to discuss the different ratings and what they mean to the pocketbook”, added Dan.

George Davis, Marketing Manager for ServiceMark in the Exton, PA office, reminds homeowners that energy efficiency rating is only one element of how much power your system will consume, and many other factors influence your energy bills during a hot summer or cold winter.

“If the system is not installed correctly, or if you have duct leakage or bad insulation, the SEER and EER won’t matter,” he says. “I’ve seen cases where a company installed a 14-SEER system for someone and saved them just as much money as a 20-SEER system by making some upgrades to their home’s insulation and over-all weatherization so they’re not losing conditioned cool or hot air.”

Government minimums

It’s helpful to learn the government’s minimum efficiency ratings in order to do some comparison shopping. In order to encourage residential energy efficiency and conservation of natural resources, the government established federal minimums for air conditioning efficiency in 1992. Click here to learn more.

Prior to 2006, manufacturers had to create air conditioners that met the 10 SEER minimum. Starting in 2006, the minimum rating was raised to 13 SEER, and as of 2015 the minimum was raised to 14 SEER for most systems except split-system air conditioners, which remain 13 across the U.S, except for a few states where the minimum was bumped to 14.

Today’s cooling systems generally achieve a minimum EER 10 rating, though some states, as detailed below, have higher requirements. In order to attain Energy Star status, air-source heat pumps and central air conditioners must maintain 12 EER for split systems and 11 for package units.

Choosing a cooling system that merely meets the minimum won’t help you achieve optimal energy efficiency, however. Instead, give high-efficiency air conditioning a second look, especially if you live in a very warm or humid climate like what we encounter in the Middle Atlantic region. The heating and cooling experts at ServiceMark recommend high-efficiency air conditioners and heat pump systems that start at 16 SEER and 13 EER.

The meeting point

Comparing two systems with a 14 SEER rating and differing EER ratings is helpful to homeowners when comparison shopping.

A system rated 14 SEER and 10.52 EER has a lower cooling capacity at 36,000 British thermal units (BTUs), but has an increased power requirement of 3,420 watts. A 14 SEER conditioner with a higher EER of 11.37 has an increased cooling capacity (37,800 BTUs), but a lower power requirement (3,320 watts). The higher EER-rated system, therefore, costs less to operate.

No matter what ratings you choose for your new system, you can take steps around the home to drive its efficiency even higher. Talk to ServiceMark about sealing air leaks and upgrading insulation, and be sure to have the ductwork sized when installing new equipment.

Proper installation and care for the system goes a long way toward helping it operate at peak efficiency for many years and your Hawthorne Plumbing, Heating, & Cooling team stand prepared to guide you in this very important decision.