Window and portable AC units work just like your central AC system. But just on a smaller scale, they utilize a closed loop consisting of compressors, coils and expansion valves to remove heat from one area and transfer it to another. The expansion valve and the evaporative oil drop, the temperature and the pressure of the refrigerant very low allowing it to absorb heat from your air and provide that sweet relief. In the summertime. The compressor and condenser coil then do the opposite heating, the refrigerant even more and allowing it to shut that heat outside. Now, the refrigerant is ready to head back into the expansion valve and start the cycle again until the thermostat's target temperature is reached to assess and compare the performance of every window and portable AC unit. We test, we head over to our temperature control test room here at CNET labs, Louisville. Here we install the test unit on the window, we rebuilt. Then we begin our experiment by raising the room temperature to 92 °F using a mini slit system and additional heaters. Once the temperature reaches 92 degrees, we turn off the heat and turn the ac unit on setting it to 60 degrees at medium fan setting a thermocouple in the ceiling allows us to collect the temperature readouts every minute. For the next 2.5 hours. We use this data to visually inspect the temperature profile achieved by each unit. Then using a count of function, we calculate how consistently the portable or window air conditioner kept the room within 5% of 68 degrees and how consistently it kept the room within 5% of the AC units, individual lowest temperature. All this information is to help you make an informed purchase decision the next time you're in the market for a window or portable AC unit.
