What do HVAC Efficiency Rating Mean?

What Do HVAC Efficiency Ratings Mean? Should I Worry?

Modern HVAC systems are designed to be as efficient as possible. Specifically, they are optimized to perform best while utilizing less energy. This, in turn, saves you money on energy bills. The efficiency of these HVAC systems is defined by what’s known as efficiency ratios. In technical terms, this is the ratio of the cooling capacity in British thermal units (BTU) per hour to the power input in watts. Let’s break down what this means and why you should care.


What are British Thermal Units (BTU)

BTU measures how much energy an AC uses to cool a space within an hour. It depends on the interior space being cooled, expressed in square feet. BTUs need to be just right, not too much, not too little. This is why the correct sizing of an AC system is crucial. The more space, the more BTU is required for efficient cooling. Overall, 20 BTU is sufficient for every foot of cooling space.

Air Conditioning Energy Efficiency Ratios

Air conditioning energy efficiency ratios are calculated for room air conditioners and central AC units. This variation gives two types of ratios: EER and SEER.

How Is EER Calculated? 

Energy Efficiency Ratios (EER) are denoted as ratings or scores, such as 15 EER. These ratios are calculated by dividing the BTU by the watts required to power the AC. For instance, the 15 EER above is arrived at by dividing 15,000 BTU by 1,000 Watts. This calculation uses a 95°F outside temperature as a constant. Both the BTU and wattage are indicated in the energy guide label.

How is the SEER efficiency rating calculated?

How Is SEER Calculated?

The Seasonal Energy Efficiency Ratio (SEER) of an AC is its cooling capacity, BTU, divided by the watts needed to cool indoor air. SEER is somewhat similar to EER but different in that it is calculated for central air conditioning systems and for specific seasons. SEER is calculated assuming an 82°F outside temperature.

Heat Pumps Efficiency Ratio

Combined heating and air conditioning systems that use heat pumps also have an efficiency ratio referred to as the Heating Seasonal Performance Factor (HSPF). This rating is defined as the ratio of heat output in BTU per hour divided by the power input in watts. Like the EER, the higher the HSPF, the more efficient it is. HSPF is also a vital rating to consider when purchasing a combined HVAC system.

What’s a Good Efficiency Rating?

Different HVAC systems have various cooling capacities, hence varying EER and SEERs. These variations might confuse you and make it hard to choose an AC based on efficiency ratings. However, these differences are there to account for the unique requirements of each HVAC user.

When deciding on an efficiency ratio, you need to consider factors such as:

  • The size of your home in square feet
  • Your ceiling height
  • The heat source for heaters
  • Power source
  • Outdoor temperatures

These factors are considered when calculating EER, SEER, and HSPF. The brand, type of HVAC system, and regulations also influence these ratings. In some states, regulations control the minimum HVAC efficiency ratings. If you are looking for a number, always know that, in most cases, the bigger the ratings, the more effective the unit.

Why care about HVAC efficiency ratings?

Why Care About HVAC Efficiency Ratings

Out of the several factors considered when choosing an AC, the efficiency rating is the most superior factor. This is because these ratings outdo other factors such as installation cost, energy consumption, durability, and maintenance. All these are considered secondary factors when choosing an AC.

For an HVAC system to be considered efficient, it has to function as intended without energy and money waste. This is why the EER and SEER ratings are calculated. One thing to note is that high-rated HVAC systems are relatively costly to install. But, the price is justified by improved heating and cooling capabilities and the use of the latest technologies.


Inefficient HVAC systems are frustrating, unsafe, and costly to maintain. This can be avoided by using highly-efficient systems. As we have seen, choosing systems with high energy efficiency ratios is the best place to start. It might be costly upfront, but the benefits become evident over time. All in all, the extra cost you pay for high-rated systems is for consistent performance down the line.

Kalka Plumbing Heating & Air – Irvine


Kalka Plumbing Heating & Air is located in Irvine and services all Orange County residents and businesses for plumbing, heating and air conditioning needs.

At Kalka Plumbing, Heating, & Air, our goal is to offer the most reasonably priced plumbing and HVAC work in Orange County and the surrounding cities. Because we value our customers, we do everything we can to reduce service costs without skimping quality. We also pride ourselves on serving our customers for almost three decades. Find us online at www.kalkaplumbingheatingandair.com. Or by phone – (949) 458-6600.


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