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The BTU on the box is not the BTU your room gets
A portable air conditioner sits inside the room it cools. Its hose and case leak heat back in, and a single hose unit pulls warm air in through every gap. The big ASHRAE number on the box ignores that. The DOE's SACC rating counts it. On the seven models here, the SACC number is 56 to 83 percent of the box number. Size your room by SACC.
Portable AC size calculator (SACC BTU)
An estimate. It uses the ENERGY STAR room AC sizing chart and its sun, people and kitchen adjustments. The ceiling step is ours: past 8 ft we scale up by height divided by 8. Compare the result with the SACC or DOE number on a portable listing, not the bigger ASHRAE number.
Find the SACC your room needs See the 7 picks
Guides
- The 7 best portable air conditioners, sized by the number that counts
Seven portable ACs from Midea, Whynter, BLACK+DECKER and Frigidaire, compared by the DOE SACC rating on each listing, hose type, window fit and noise.
- What size portable air conditioner do you need?
Enter room size, ceiling, sun and people to estimate the SACC BTU a portable air conditioner needs, from the ENERGY STAR sizing chart.
- ASHRAE BTU vs SACC: why your portable AC feels smaller than the box
A portable AC box shows the ASHRAE BTU. The DOE SACC rating counts heat from the hose and air that leaks in. Here is the gap on seven real listings.
- Single hose or dual hose?
A single hose portable AC pulls replacement air in from the rest of your home. A dual hose unit brings it from outside. What that does to SACC, and which picks use which.
- Will the window kit fit your window?
Portable AC window kits fit a range of openings. The ranges on seven listings, what to do with crank-out casement windows, and how to seal the gaps.
- Where the water goes, and when you have to drain it
Where the water goes in a portable air conditioner, when you have to drain it, how a continuous drain hose works, and a CPSC recall to know about.
- What a portable AC costs to run, and how loud it is
How many kWh a portable air conditioner uses, how to turn that into cost with your own electric rate, and what the noise numbers on listings mean.
- Portable or window air conditioner?
A window AC keeps its hot side and compressor outdoors. A portable does not. When a portable still makes sense, how their BTU ratings compare, and a window unit recall.