MERV. ENERGY STAR. SEER. HSPF. AFUE. If you’ve been shopping for a new furnace or air conditioner, a lot of acronyms and names are thrown at you.

But what do they all mean?

Those words actually hold a lot of weight for heating and cooling systems as they’re all energy ratings that determine how efficient the air conditioner, HVAC, or furnace you’re buying is. And, yes, they’re important ratings to look out for as it largely determines the cost to purchase and operate the device.

So, what are these energy efficiency ratings? How do they work? Which ratings are best? We explain all that and more down below.

1. What Does ‘Energy Rating’ Mean?

Essentially, an energy rating is a measurement of how well a device can consume energy. For example, if an air conditioner output is high, but its electric energy input is low, that’s a very efficient air conditioner and will receive a positive energy rating. If both the output and input are high, the rating will be neutral. And as you may have guessed, if the output is low but the input is high, the air conditioner in question will receive a poor energy rating.

Why is this important to you?

Well, if the device has a low energy rating, that means your energy bills will increase. So, not only will you be buying a new air conditioner, but you’ll also have to pay up each month for its high energy consumption. Whereas, if the unit has a high energy rating, you’ll save more in the long run thanks to its efficient use of electricity.

2. How Do Energy Ratings Work?

Energy ratings take the electrical energy input from heating and cooling devices, comparing input against the energy output. The results determine energy performance against others in its class and places them on a scale. The higher on the scale they’re placed, the more efficient the appliance is.

3. How Do You Read Energy Ratings?

The key to reading energy ratings is to know the types of energy ratings and their scales.

SEER – SEER is the Seasonal Energy Efficiency Ratio and is used to rate air conditioners, heat pumps, and other cooling systems. The keyword in this energy rating is seasonal. SEER ratings attempt to determine the energy efficiency of cooling systems under average temperatures (lower than 82 degrees). And just like most energy ratings, the higher the number, the more efficient the unit. However, keep in mind that a 16-SEER wouldn’t achieve that same rating under higher temperatures.  

Scale: 8 – 30

 

EER – EER stands for the Energy Efficiency Ratio and is the same as SEER, but with higher temperature requirements. Instead, EER rates cooling systems using extreme operating temperatures, higher than 95 degrees. This is helpful as it allows homeowners to see how well their cooling system will perform under the maximum load. And again, the higher the number, the more efficient the unit.

Scale: 8 – 30

 

ENERGY STAR – ENERGY STAR is both a program and a rating. You may see the ENERGY STAR logo on everything from washing machines to office buildings. If you see the logo on a product, you’ll know with certainty that the product contributes significant energy savings as the logo is only placed on products when it meets minimum rating requirements. For example, any air conditioner with a SEER rating above 14.5 qualifies as an ENERGY STAR product.

Scale: None

 

HSPF – HSPF is the Heating Season Performance Factor. The HSPF is used to measure the heating efficiency of air source heat pumps (for cooling efficiency, SEER is used). Some people even refer to HSPF as the SEER rating for winter.

Scale: 7 – 10

 

AFUE – AFUE stands for Annual Fuel Utilization Efficiency and is used to determine the efficiency of residential gas furnaces and boilers. It uses the percent of heat produced for every dollar of fuel consumed to rate heating devices. For example, an AFUE of 80 means that 80% of the fuel you purchased will be turned into heat — the remaining 20% is consumed during the process of producing and distributing heat.

Scale: 78 – 99

 

MERV – MERV stands for Minimum Efficiency Reporting Value and is used to rate furnace and air conditioning filters. The higher the number, the more efficient the air filter is at trapping particles. For maximum heating and cooling efficiency, it’s important that your air filters are effective at trapping contaminants so they aren’t allowed to restrict your system’s airflow, making your system consume more energy.

Scale: 1 – 16

4. What Is a Good Energy Rating for Air Conditioners?

For air conditioners, pay close attention to the SEER, EER, and ENERGY STAR ratings. The minimum SEER or EER rating you can purchase is 13, but anything over a 14.5 will offer energy savings in the long run. And before you go all in on a high rated air conditioner, remember that your climate matters. If you live in California, you probably won’t run your air conditioner all year long and therefore won’t be paying as many bills.

Lastly, if you live in a hot climate like Arizona, Texas, or Florida, an EER rating is probably more accurate for what you will experience over a SEER rating as it accounts for those extreme temps.

5. What Is a Good Energy Efficiency Rating for Furnaces?

If you’re shopping around for furnaces, you’ll want to pay attention to the AFUE and ENERGY STAR ratings. An AFUE of 78 is the minimum energy efficiency allowed for residential homes. Furnaces in the 80 – 89 range are considered efficient, and units rated over 90 are considered best-in-class, high-efficiency furnaces.

First-Rate Heating and Cooling

Energy ratings are tricky, often confusing numbers for homeowners to understand with different scales, letters, and meanings behind each. But, hopefully, as HVAC professionals with over a century of experience, we were able to answer your questions and help you find a system that reduces your heating and cooling costs.

Sick of seeing your energy bills skyrocket? Check out our guides on how to reduce heating or cooling costs below:

• How to Reduce Air Conditioning Costs: 15 Tips for Efficient Air Conditioning
• How to Save on Heating Costs: Tips & Tricks for Furnace Efficiency