When you’ve been shopping for a new portable air conditioner, you may have noticed two different BTU ratings: ASHRAE vs SACC BTU Rating. Why are there two numbers coming up on your search, and what do they mean exactly? So, let’s start to learn about air conditioner (AC) BTU meaning and Portable AC BTU Guidelines. Also, we need to understand what BTU SACC means.


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What Is A BTU in AC?

British Thermal Unit (BTU) is a measure of the cooling capacity of an air conditioner. It is usually the most important consideration when purchasing a new portable air conditioner. When comparing portable air conditioners, it is important to consider various aspects. The higher the BTU DOE in AC, the more powerful the air conditioner. Simples? Until it comes to seeing different BTUs for the same unit. So what does BTU stand for in AC? It can help you determine the kind of air conditioner you need for a home your size.

What Is The ASHRAE Definition?

ASHRAE ratings evolved under old test standards developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). In ASHRAE testing, portable air conditioners are set to run in nearly perfect conditions. However, this does not always translate to how it would work in real-life situations.

When performing ASHRAE BTU testing on portable ACs, 80 degrees Fahrenheit temperature and 51% relative humidity are used as baselines. One major limitation of this rating is that it fails to consider that we don’t live in a world where our use of ACs is devoid of any imperfection. The temperature and humidity level in our rooms may be higher or lower than the ASHRAE testing requirements, which changes the cooling capacity of the air conditioner.

A new testing process was developed to get a better idea of how a portable air conditioner works in changing different conditions, the SACC rating was invented.

What changed?

To help better reflect the energy efficiency of each portable air conditioner, the FTC rolled out new labeling requirements to improve accuracy. In past years, portable ACs were rated similarly to other air conditioning systems using the ASHRAE standard, which was unintentionally misleading customers to compare portable units to stationary units.

What do BTUs Mean for your AC?

When it comes to air conditioners, size matters. Too small of a unit will continuously run and not adequately cool a room, whereas, too large of a unit will cycle off too quickly, not properly removing moisture from the air, and may even freeze. It also leads to higher energy bills!

So what about ASHRAE Sizing Guidelines for Portable ACs? To determine the right size, refer to the BTU rating. The bigger room is cooled by an appliance with more BTU. You can check this sizing list as well; this might give you some clue about what size unit you need:

  • 100 up to 150 sq. ft. = 5,000 BTUs per hour
  • 150 up to 250 sq. ft. = 6,000 BTUs per hour
  • 250 up to 300 sq. ft. = 7,000 BTUs per hour
  • 300 up to 350 sq. ft. = 8,000 BTUs per hour
  • 350 up to 400 sq. ft. = 9,000 BTUs per hour
  • 400 up to 450 sq. ft. = 10,000 BTUs per hour
  • 450 up to 550 sq. ft. = 12,000 BTUs per hour
  • 550 up to 700 sq. ft. = 14,000 BTUs per hour

What is the difference in the ratings?

The ASHRAE test was done in a perfect situation while SACC is based on actual conditions. The SACC rating method is a more precise way of determining an area that can be cooled economically.

Is there any way I can tell whether the rating is ASHRAE or SACC?

In many cases, not all products have ever stated – that which BTU rating system was displayed on the box or product label. It may be necessary to look at the detailed specifications of a product to identify the actual rating system. The transition to SACC for portable air conditioners began with units made in 2020. As of 2024, all portables use SACC instead of ASHRAE in their naming sequence. This will necessitate referring to the detailed specifications if in doubt.

Not all manufacturers have moved to indicate the SACC rating on their product pages or even within their naming scheme hence validation is key.

What does it mean by SACC?

This new SACC rate takes into consideration weighted-average BTU/hour performance that under extreme conditions incorporates infiltration air effect and duct heat transfer from environmental variables affecting portable ACs. Hence, the earlier ASHRAE standards were not as thorough in accessing all these factors that affect a portable AC unit.

With the new testing methodology used, the SACC rating might appear lower than past ratings on some unit packages though the model has not changed.

What’s going to happen to my portable AC or future portable ACs?

Accordingly, any brand-new portable air conditioner made after 2017 will have a listed SACC rating. For the consumer to compare both ratings, some manufacturers may prefer indicating both ASHRAE and SACC ratings on their packaging.

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ASHRAE Guidelines for Portable AC Size

The newly introduced Energy Guide labels for portable air conditioners are meant to be more reflective of each model’s energy efficiency. What does this new labeling accomplish?

  • Accurate: Enables consumers to get clear and accurate information about the energy efficiency of portable air conditioners.
  • Mandatory Changes: Retailers and manufacturers must correct their advertisements with up-to-date details that are aimed at guiding customers.

Why Did It Alter?

FTC, a body that demands changes in Energy Guide labels, decided to change it as there are new guidelines for energy testing of single-hose and dual-hose portable air conditioners provided by the Department of Energy (DOE). The new energy testing guidelines were first proposed in February 2015 and officially went into effect in June 2016.

When the new testing protocol was implemented, an unintended consequence was that prior inconsistent testing may have caused Energy Guide labels that misled customers about how portable ACs compared with other types of air conditioners.

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What Are the Changes?

Cooling and heating test requirements were altered thereby revising an old rating system and introducing a new one.

  • Combined Energy Efficiency Ratio (CEER): It is a measure of both running and standby power consumption when the unit is on, but not running.
  • Seasonally Adjusted Cooling Capacity (SACC): This rating is in BTU/hour representing the average results from various tests which could include some extreme cases. It is concluded that Portable ACs appeared to be more efficient than they are if tested using this method.
  • Recommended Room Size: To eliminate the hassle of trying to estimate how many BTUs you need for one room, all products will have a clear statement of the maximum square footage for which that model is designed.
  • DOE SACC Ratings: The BTU DOE SACC rating depicted on the product page contents is also in compliance with federal laws. However, the thing that must be kept in mind is that this new rating was made using updated testing standards therefore; the recommended maximum BTUs are lower than before. In summary, it does not mean that there have been any changes to the air conditioner.
  • ASHRAE Rating: During this interim period, ASHRAE BTU ratings will still appear beside old unit lists on web pages.
  • Manufacturer Packaging: Many manufacturers will put last year’s DOE rating together with the new one on their packaging throughout this transition year.


ASHRAE BTU ratings are determined by testing the performance of portable air conditioners under ideal conditions (80° F/51% RH), whereas SACC BTU ratings are calculated based on a weighted average of a portable air conditioner's performance at different temperatures and humidity levels.