8,000 BTU vs. 10,000 BTU Portable A/C Unit – Will the 10,000 BTU unit cool the same room X degrees more if all other variables same the same

air-conditioning

My 150 square foot bedroom has central air and stays around 80 degrees F (sometimes a few degrees more or less).

8,000 BTU Results

I purchased a Frigidaire 8,000 BTU unit from the Home Depot to cool the room. It is able to keep the room at 68 to 72 degrees F and runs constantly (I have it set to 62 – it occasionally switches to fan only mode to let the compressor rest).

10,000 BTU Question

I would like to cool the room more and remove more humidity. The Home Depot sells the same series model in a 10,000 BTU variation. If I upgrade to 10,000 BTUs will I see a difference? I would like to get the room to stay at 64 to 68 degrees F at 50% or lower relative humidity.

I am guessing that the 10,000 BTU model will also run constantly (occasionally going to fan only mode) as it will never be able to reach the set temperature of 62 – I am fine with this as I am replacing my old unit which did the same thing and lasted for 8 years.

My understanding is that portable air conditioners have overrated BTUs as they are no where as efficient as window units because the compressor is inside the room.

Best Answer

Basically, a BTU is the amount of heat required to raise the temperature of one pound of water (at or near 39.2 degrees Fahrenheit) by one degree Fahrenheit

So, an AC unit with the capacity of 10,000 BTU's per hour can cool more air (a bigger room) at the same rate, or the same amount of air faster than a unit with a capacity of 8,000 BTU's per hour.

So, in the exact same room under the exact same conditions, the larger AC can maintain a lower temperature than the smaller one.

If you have the AC set at 62°F and it never reaches that temperature and shuts off then the unit is overloaded and has to rest the compressor to keep from freezing up. Or it is possible the freezestat is shutting the compressor off when the evaporator coil freezes up. Either way, setting it to 62° is futile since it apparently cannot get to that temperature.

It appears your current unit can only get to 68° so that would be your maximum low set point for that unit.

A larger unit should be able to get to a lower temperature under the same conditions. But it still may never make it to 62°.

Good luck!

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