Yeah, there's something fundamentally flawed about the assumption in that statement.

The A/C unit will simply try to cool things down to the temperature you set it to. The A/C unit doesn't have a "try harder" setting. For instance, turning things down to 60 isn't going to make the unit work any harder than if you turned it down to 72. It's working at its maximum efficiency at all times.

If you turn it down to 72 and your house isn't getting cold enough, you're running into the following possible issues:

- Air conditioning unit is malfunctioning and not cooling at its full potential efficiency.

- Air conditioning unit is not large and powerful enough for your house and/or your geographic location.

- House insulation is extremely poor, so heat leaks in through the walls and especially the attic, negating all the hard work the A/C is doing.

I lived in a house for years which fell into that third camp. It was pretty miserable.