I can only find a 14,000 btu window a/c for my small room. I really only need an 8,000 or 10,000 btu but can’t get one in my area. I was just wondering if I kept a/c on lowest speed, would the btu be less?? Thanks!

  • 2
    I think the BTUs deal with the compressor/cooling system, while the fan only deals with air movement, so the fan speed will not change the BTUs, but will change how fast the room cools.
    – crip659
    Commented Oct 4, 2023 at 22:03

1 Answer 1


The air conditioner has a thermostat, so hardly ever uses its maximum BTU cooling capacity. Being oversized just means it will cycle off more often, but the room will still be at the temperature you set.

However, an oversized air conditioner has a few possible disadvantages:

  • It would be a bit less effective at removing humidity from the air.
  • It draws more current when cycling on. Electric bills won't be appreciably higher, because the compressor would not run as long as that in a small unit, but the wiring must be able to handle the higher current.
  • It likely would cost a bit more than a smaller unit.

That said, a unit 50% larger than ideal likely would not be a major issue.

  • note that an inverter AC will run at lower BTUs when required, this advice is good for non-inverting ones though, which is more of the older ones and cheaper newer ones.
    – dandavis
    Commented Oct 6, 2023 at 4:40

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