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Understanding HVAC Efficiency Ratings: SEER, EER, HSPF, and AFUE

Updated: Aug 4, 2023

In the world of HVAC (Heating, Ventilation, and Air Conditioning), a handful of acronyms significantly impact your comfort and monthly energy bills. Four of these key terms - SEER, EER, HSPF, and AFUE – all represent different methods of measuring the efficiency of your HVAC equipment. Understanding these ratings can help you make an informed decision when buying or upgrading your system.

SEER: Seasonal Energy Efficiency Ratio SEER measures the cooling efficiency of your air conditioner or heat pump over the course of a typical cooling season. It’s calculated by dividing the cooling output over a cooling season by the total electrical energy input during the same timeframe. A higher SEER rating indicates greater energy efficiency, which usually leads to lower energy costs. However, the overall efficiency of your system can also depend on the size of your home, your ductwork, and other variables. An HVAC professional can provide valuable advice tailored to your unique situation.

EER: Energy Efficiency Ratio While SEER measures efficiency over an entire season, the Energy Efficiency Ratio (EER) evaluates the efficiency of an AC or heat pump under one specific set of conditions, i.e., an outdoor temperature of 95°F and an indoor temperature of 80°F with 50% relative humidity. Because EER ratings reflect performance under consistent conditions, they’re useful for comparing the efficiency of different systems in a controlled environment. However, they may not fully reflect how a unit will perform under varying weather conditions throughout a season.

HSPF: Heating Seasonal Performance Factor For those of us who rely on heat pumps to warm our homes during the chilly months, the Heating Seasonal Performance Factor (HSPF) is a crucial term to understand. It evaluates a heat pump's efficiency over the course of a heating season. Like SEER, HSPF is a seasonal measure and is calculated by dividing the total heating output of a heat pump during a heating season by its total electricity consumption during the same period. A higher HSPF rating indicates greater energy efficiency and lower energy costs.

AFUE: Annual Fuel Utilization Efficiency The Annual Fuel Utilization Efficiency (AFUE) rating applies to furnaces and boilers and is a measure of heating efficiency in converting fuel to energy. A furnace or boiler's AFUE rating is the ratio of heat output to the total energy consumed by the unit over a year. An AFUE rating of 90% means that 90% of the energy in the fuel is being converted to heat, while 10% escapes as exhaust. In conclusion, these four efficiency ratings – SEER, EER, HSPF, and AFUE – can provide valuable insights when you're considering an upgrade to your HVAC system. By understanding these metrics, you can make an informed choice that will not only maintain comfort in your home but also effectively manage your energy costs.

Remember that every home is unique, and there are many factors to consider when choosing the right HVAC equipment. If you need expert advice on HVAC systems, don't hesitate to reach out to us at Salmark HVAC. We're here to help you understand your heating and cooling needs and to ensure you get the most efficient system for your home.


Salmark HVAC


Lemont, IL

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