When shopping for a new portable air conditioner, you've probably encountered two different BTU ratings: ASHRAE and SACC. Why are you seeing these two numbers, and what exactly do they mean? Keep reading to find out.
What Is A BTU?
A British Thermal Unit (BTU) measures an air conditioner’s cooling capacity. It's typically considered the most important factor when buying a new portable air conditioner.
The higher the BTU, the more powerful the air conditioner. Simple right? It is until you start seeing different BTUs for the same air conditioner.
What Is The ASHRAE Definition?
The ASHRAE rating was developed under old testing standards devised by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). During ASHRAE testing, portable air conditioners are examined under ideal conditions. However, these testing conditions don't always mirror how the air conditioner will perform in real-life applications.
ASHRAE BTU testing is conducted to see how the portable air conditioner performs in conditions of 80 degrees Fahrenheit and 51 percent relative humidity. The main drawback of the ASHRAE rating is that it doesn't account for the fact that we don't use air conditioners in perfect conditions. 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, the SACC rating, was developed to better understand how a portable air conditioner works in changing conditions.
What's The Definition of SACC?
In 2017, the Department of Energy (DOE) introduced a new rating for portable air conditioners called the SACC rating.
The Seasonally Adjusted Cooling Capacity (SACC) rating is essentially a weighted average of a portable air conditioner's performance at various temperatures and humidity levels.
Additionally, the DOE accounts for the infiltration of air, or the amount of air the unit is bringing into your space as it exhausts warm air, in single-hose portable air conditioners.
See The DOE Energy Conservation Standards For Portable Air Conditioners
What All The Portable Air Conditioner Testing Means
When comparing portable air conditioners, you will come across two types of BTU ratings: the ASHRAE BTU rating and the SACC BTU rating. It's important to note that the SACC rating is always lower than the ASHRAE rating.
But this lower rating doesn't indicate any changes in the portable air conditioner's internal components or operation. It simply means that the air conditioner has been tested under different conditions.
ASHRAE to SACC BTU Comparison
Since portable air conditioners are tested under different conditions, it's difficult to calculate an exact conversion from ASHRAE BTUs to SACC BTUs. The chart below provides a general guide for comparing the two ratings.
| ASHRAE vs. SACC BTU Comparison | ||
|---|---|---|
Old ASHRAE BTU |
New DOE BTU SACC |
Coverage Area |
8,000 BTUs |
4,000 - 5,000 BTUs |
Up To 250 Sq Ft |
9,000 BTUs |
5,000 - 6,000 BTUs |
Up To 300 Sq Ft |
10,000 BTUs |
6,000 - 7,000 BTUs |
Up To 350 Sq Ft |
11,000 BTUs |
7,000 - 8,000 BTUs |
Up To 400 Sq Ft |
12,000 BTUs |
8,000 - 9,000 BTUs |
Up To 450 Sq Ft |
13,000 BTUs |
9,000 - 10,000 BTUs |
Up To 500 Sq Ft |
14,000 BTUs |
10,000 - 11,000 BTUs |
Up To 600 Sq Ft |
15,000 BTUs |
11,000 - 12,000 BTUs |
600 Sq Ft+ |
In Summary
ASHRAE BTU ratings are determined by testing the performance of portable air conditioners under ideal conditions (80 degrees F and 51 percent 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.
Click Here To Read More About Portable Air Conditioner BTU Guidelines
