If you’re looking for an AC unit for your home, you should know the various ratings and specifications. As of January 1, 2023, all new AC units must be SEER2 certified and have SEER2 ratings — SEER2 is a measure of the AC’s energy efficiency. If you have an AC unit that was made before 2023, it likely has the older SEER rating. The U.S. Department of Energy regulates the minimum SEER/SEER2 requirements for AC manufacturers.
Another critical rating of AC units is the cooling capacity, measured in tons or British Thermal Units (BTUs) (1 ton of cooling capacity equals 12,000 BTUs/hour). There are several other important AC ratings, such as ENERGY STAR and HSPF, which we will cover in this comprehensive guide.
Related: Air Conditioning Calculations
Air Conditioner Ratings & Typical Specifications
Here are some of the air conditioner ratings you may encounter in the brochures or specifications of the central air conditioner or heat pump unit.
Related: What is an Air Conditioner Btu?
1. Capacity
The capacity is the most basic specification that you should look out for. In ductless split, the range of cooling capacity can go from 9,000 Btu/h to over 30,000 Btu/h. The amount of cooling needed by the space will be used to determine the capacity of the air conditioner needed.
2. COP(Coefficient of Performance)
This coefficient is the ratio of the cooling capacity(W) versus power consumption(W).
COP= Cooling Capacity(W)/Power Consumption(W)
The higher the COP, the higher the efficiency of the air conditioner. Usually, the value ranges from 2-4, but in recent years, the use of inverter compressors has enabled this coefficient to go higher than 4. This formula is also applicable to heat pump systems. See the explanation on heat pump COP.
If the cooling capacity is given in Btu/h, you can convert it to Watt by dividing it by 3.412.
1W= 3.4121 Btu/h
3. EER (Energy Efficiency Ratio)
This rating was established by ARI or Air Conditioning and Refrigeration Institute in 1975 for manufacturers to rate their equipment so that consumers or consultants can tell the cooling efficiency of the AC system by just looking at the specifications provided.
This rating is obtained by dividing the cooling capacity (Btu/h) by the input power (Watt). The rating points are at 80 °F dry bulb/67 °F wet bulb indoor temperature and 95 °F dry bulb/75 °F wet bulb outdoor temperatures.
For instance, if you look at the brochure and the unit has a Cooling Capacity = 25,000 Btu/h and Input Power = 2,400 W,
EER = (25,000 Btu/h)/2400W = 10.42
The larger the value of EER, the more efficient the HVAC system is. Therefore, choose a bigger EER if you are comparing two pieces of equipment.
The EER has a limitation in that it is measured only when the unit is in steady-state condition. The starting-up and shutdown cycles are not included in the calculation.
Therefore, this rating does not give a complete picture of the efficiency of the unit. So, a better efficiency ratio known as the Seasonal Energy Efficiency Ratio or SEER was developed.
Choose wisely these air conditioner ratings as the efficiency of the unit will drop as the unit ages over the years.
4. SEER (Seasonal Energy Efficiency Ratio)
The criteria that make up the SEER rating calculation are determined by the AHRI (Air Conditioning, Heating, and Refrigeration Institute). All manufacturers’ equipment ratings are published in their catalogs. SEER takes into consideration non-steady state conditions such as the start-up and shutdown cycles of the air conditioner.
Since Jan 23, 2006, all central split-cooling systems produced in the US must have a SEER rating. Since 2006, the U.S. DOE has raised the minimum SEER ratings for new AC units several times.
When you’re picking out a new AC unit, I recommend choosing one with a higher SEER rating, as It means the unit is more efficient and will lower your energy bills. However, the trade-off in choosing a higher SEER is that usually, the initial cost of the equipment will be higher.
This ratio is obtained by dividing the total cooling that the equipment is able to provide over the entire season (Btu) by the total energy in Watts-hours it will consume (Wh).
5. SEER2 (Seasonal Energy Efficiency Ratio 2)
SEER2 is the newest energy efficiency rating for air conditioners and heat pumps — it officially replaced the older SEER rating as of January 1, 2023. SEER2 uses a different testing procedure that more accurately reflects real-world performance.
The minimum SEER2 rating varies by where you live in the U.S. – 13.4 SEER2 is the minimum in the North, and 14.3 SEER2 is the minimum in the South. Higher SEER2 ratings mean the air conditioning system has better efficiency and lower energy costs.
6. HSPF (Heating Seasonal Performance Factor)
This ratio is used to determine the efficiency of air source heat pump equipment.
It applies to the heating mode by which the total heating used during the entire season is divided by the energy in Watt-hours that it consumed.
A ratio of greater than 8 is considered an efficient equipment. However, the advancement of better control and inverter compressors have enabled units to have HSPF up to 13.
You will see this figure moving upwards as newer designs are being developed.
For example, a ductless split unit heat pump delivering 100,000,000 Btu during the entire season and consuming 12,000 kWh will have an HSPF of:
HSPF = 100,000,000 Btu/12,000 kWh = 8.33
The higher the HSPF, the better the unit is.
7. CEER (Combined Energy Efficiency Ratio)
The Department of Energy (DoE) of the United States has been using this rating for room air conditioners/window air conditioners to specify the efficiency of them since June 2014.
CEER is defined as ‘The ratio of measured cooling output (in BTU per hour) to measured average electrical energy input (in Watts) and measured standby/off-mode power consumption (in Watts.).’
This ratio is more accurate as it takes into consideration the energy consumed while running as well as when the unit is on standby mode. During standby mode, the unit is plugged into the power but is not running. The control that is made up of electronic components is consuming power even though in standby mode.
If you are looking for a unit, look for a higher CEER as it will save you energy cost in the long run even though it is more expensive.
For example, the Midea inverter model MAW08V1QWT, with a cooling capacity of 8,000 Btu, has a CEER rating of 15. This rating is shown on the energy guide in the figure below.
8. Noise or Sound Level
In a ductless split unit, there is an indoor and outdoor unit. The specifications will state the noise level of both the indoor (evaporator) and outdoor (condenser). The lower the decibel (dBA) value, the quieter it is. Hence, if you are installing a unit in the study room, choose a lower dB level.
The evaporator is always quieter than the condenser unit. Depending on the capacity, the indoor noise level can go down to below 21 dBA, and the outdoor unit can go higher than 50 dBA. Higher-capacity equipment will have higher sound levels compared to lower-capacity equipment.
9. Refrigerant
The refrigerant used will also determine the pricing of the unit. For example, R22 will be phased out soon, whereas R410A is the more ozone-friendly refrigerant.
The cost of the newer refrigerant is more costly but you will be helping to reduce the amount of gas that is harmful to the ozone from being used. Ask the dealer about the refrigerant used and get their advice on future replacement and service.
10. ENERGY STAR
Look out for ENERGY STAR rating of the equipment. An equipment with this rating shows that the equipment is designed to save energy hence reducing your electricity bills as well as protecting our environment.
Units that are qualified for ENERGY STAR ratings are listed on the official website. See the ENERGY STAR air conditioner ratings here.
2024 Efficiency Requirements for residential central AC and heat pumps
The minimum efficiency standards for residential central air conditioning and air-sourced heat pump systems sold in the United States increased on Jan 1, 2023.
As such, newly manufactured AC units and heat pumps (split systems) must meet the below SEER2 requirements.
- 14 SEER and 13.4 SEER2 for residential systems in the northern part of the United States. The previous minimum was 13 SEER.
- 15 SEER and 14.3 SEER2 for the southern part of the United States. The previous minimum was 14 SEER.
The new minimum HSPF (effective since Jan 1, 2023) for heat pumps is 8.8 HSPF compared to the previous 8.2 HSPF minimum.
These requirements do not affect the air conditioner you already have installed in your home. For example, if your AC unit was installed 10 years ago and has an 11 SEER rating, you won’t need to replace it. However, if it is at the end of its lifespan and you need a new one, you’ll only be able to get one with a SEER2 rating that meets the above requirements from the U.S. DOE.
Final Thoughts
Knowing these critical air conditioner ratings is crucial when selecting a new unit for your home. Key ratings to consider include SEER2 for efficiency, cooling capacity in tons or BTUs, and EER for performance at a specific temperature. As of January 1, 2023, all new units must meet minimum SEER2 requirements set by the U.S. Department of Energy. If you’re unsure what ratings you should get for your new air conditioning unit, consult with a local HVAC company for help.
Frequently Asked Questions
What is a good SEER2 rating for an air conditioner?
If you want the best energy savings, consider choosing an AC unit with a 16 SEER2 rating or higher from a top air conditioning brand like Rheem, Amana, American Standard, Trane, Lennox, York, or Goodman. However, it will cost more upfront than a lower SEER2 rating.
How does the cooling capacity of an air conditioner affect its performance?
The cooling capacity (measured in BTUs or tons) directly relates to how many square feet it can cool. To make sure you get the correct cooling capacity for your home’s square footage, hire an HVAC technician.
Do higher SEER2 ratings always mean better performance?
Yes, a high SEER rating will always have better performance and more energy savings than lower SEER2 ratings. That’s assuming you have a reliable AC brand, it is properly installed, the correct size, sealed ductwork, etc.
