efficiency ratings HVAC systems

Understanding Efficiency Ratings for New HVAC Systems

When considering a new heating or cooling system for your home, efficiency is naturally one of your top priorities. You want a system that will keep you and your family comfortable throughout the year without generating a massive utility bill at the end of each month.

At Action Plumbing, Heating, Air & Electrical, we’ll assist you with every step of an AC or furnace installation, from selecting the optimal brand and model for your home to installing it safely and efficiently for long-term use. When it comes to understanding how efficient a new system will be, there are a few different efficiency ratings used in the heating and cooling world – let’s go over some of the most common and what they mean for your system.


For systems that specifically use a boiler or a furnace for heating, the AFUE metric is used to represent the fuel efficiency the system uses. It tracks the amount of fuel used when the unit works, then converts that into a percentage – so if your AFUE number is 90, this means the system used 90% of the fuel for its standard purposes but lost 10% to exhaust and other runoff.

As you might have guessed, this means you want your AFUE number to be on the higher side. The best furnaces and boilers are close to 100, meaning they utilize almost all their fuel efficiently.


Short for Seasonal Energy Efficiency Ratio, the SEER rating is a well-known ratio that measures the cooling produced compared to the electricity used in an AC system. SEER ratings range from 10.9 up to 23 within standard systems. Once again, the higher the number, the more efficient the system is.


This is a metric similar to SEER, but without the seasonal output variable. It’s determined by a single outside temperature and a single inside temperature, meaning it doesn’t factor seasonal changes here and is a bit more of a general metric rather than a specific one. It’s commonly used to rate window AC units or single-room air conditioning units, because the SEER rating isn’t practical for these.


This metric stands for Heating Seasonal Performance Factor, and is used for heat pumps primarily. It’s found by dividing the overall heat output by the total electricity used, with ratings ranging up to 10 – the closer the number is to 10, the more efficient the system is.


Finally, a rarer metric used mostly for rate-split systems is the IEER rating, which evaluates the system’s output at varying times based on specific conditions. This is valuable for split systems, which work utilizing multiple air handlers and in different condition ranges.

For more on the various efficiency ratings you might see when selecting a new heating or cooling system, or to learn about any of our HVAC or plumbing services, speak to the staff at Action Plumbing, Heating, Air & Electrical today.