Energy Efficiency Ratings and What They Measure
Updated: May 11
If you spend any time at all doing research on selecting an optimal HVAC unit for your home or business, you will come across various efficiency ratings. These rating standards can vary and are not necessarily intuitive for first time buyers. If these ratings seem overwhelming or just down right confusing, don’t fret. We are here to help.
The first thing you should know about energy efficiency rates is: the better the score the lower your long term costs. That does not mean that the upfront cost will decrease, in fact the opposite is true. Often more energy efficient units run on the high end for initial purchase cost. However, the reduction in energy bills is sure to save you money in the long term. Be sure to find the unit that that fits you needs. If you buy a unit that is too big for a space, you are just wasting resources. If you get a unit too small for your needs it is likely to wear out sooner than expected and struggle to provide the comfortable environment you are seeking.
Top Five Energy Efficiency Ratings You Should Know:
The first is the Energy Star Rating. Originally created by the US Department of Energy in the early 90’s, this rating is now regulated and managed by the EPA. For many in the US, this is the standard nationally recognized symbol for efficient use of energy. Because this rating is given by the EPA and not a company, the results are deemed unbiased.
The Energy Star Rating uses BTUs (British Thermal Units) to measure energy. One BTU is the unit of energy needed to raise the temperature of one pound of liquid water by a single degree when at sea level. HVAC equipment utilizing the Energy Star Rating determine efficiency by how many BTUs a product can add or remove from the air within one hour.
The SEER (Seasonal Energy Efficiency Ratio) focuses on the amount of energy needed in both air conditioners and heat pumps to effectively cool a home. While some hotter regions have higher requirements, all HVAC systems are required to have a minimum SEER rating of 14 (as of 2023). This tells the user how much energy will be needed to cool an entire room versus how much is needed to run the HVAC unit. In Texas, it is standard to have a SEER rating of at least 15. If you are looking for a way to determine how much you will spend annually on energy costs, this is a rating you want to pay close attention to.
Another commonly used rating system for energy efficiency in the HVAC industry is the AFUE Energy Rating. This acronym stands “annual fuel utilization efficiency.” The AFUE rating communicates how effectively a furnace utilizes fuel and converts it into warm air. These are standard ratings that are required by the Department of Energy to appear on all furnaces, so it is simple to compare various units to determine where you will see the most savings in energy efficiency. Calculating this rating is exactly what you would expect- comparing the amount of fuel needed to run the unit over the course of a year compared to amount of heating output produced during that same period of time. The resulting rating is the efficiency of the unit on an average day.
The next rating is the HSPF (heating seasonal performance factor) rating. This rating is exclusive to heat pumps, and is required by law to be at least 8.2 along with an accompanying Energy Star Rating of 8.5 or higher. This measures the heat produced during heating season compared to the electricity consumed.
Easily compared to the SEER, the EER (energy efficiency ratio) communicates how well a system can provide a comfortable environment. The same formula used to determine the SEER is used here. The primary difference is that the SEER measures a central air conditioner as it turns on and off in a variety of temperatures while the EER focuses on a single room unit running constantly at 95 degrees.