# What exactly do the range of numbers (1 to 7) mean on the temperature knob/dial on a basic window air conditioning unit?

I just purchased a new, very nice and basic (5,000BTU) in-window air conditioner and it does the job for my basic needs. But I have a question I probably have had for years but never had a proper venue to ask it: What the heck do the seemingly arbitrary numbers on the temperature dial mean? See picture below.

I completely understand how a value of “1” is the lowest (warmer) setting and “7” is the highest (cooler) setting, but what relative temperatures do these values relate to? And heck, why does the dial go from 1 to 7 instead of something more seemingly commonsense like 1 to 10?

• Another concept to consider is that almost no two thermostats or thermometers read the exact same tempature. We have two wall thermostats that we added 3 more random digital thermoters temporarily. Between 68 and 80 they all varied. Another place I've noticed this phenomenon is the pool: two old style mercury pool thermometers, one automation system, and a digital display on the heater never all exactly agree. Not having actual tempature on the dial probably saves a lot of calls to customer service. (For example: I set it to 75 but it didn't go off til 70 or vice versa) Jun 26, 2016 at 22:02
• @Tyson Nice comment. Could possibly be a full answer as well. Jun 26, 2016 at 23:10

The numbers are completely arbitrary, and are whatever the product manager or artist at the manufacturer decided they should be. They might be standardized within a company's product line. If these are private-label units, all bets are off.

Numbers instead of real degrees means they used a thermostat too cheap to be consistent from unit to unit, so they couldn't print degrees and have that be meaningful.

Alternate explanation: they market the identical unit in several countries, and one of them uses Fahrenheit, so rather than have 2 scales, they have none.

• Very much agree. Note how the scale is not even linear as the spacing from 5 to 6 is much greater than from say 2 to 3. Jun 26, 2016 at 9:06
• Yeah, cheaper rheostats are even (so many ohms per degree) but the circuit often needs a log or 1/x curve for the marks to be linear. They make rheostats with varying resistance like that, more expensive of course. Jun 26, 2016 at 9:22
• The temperature control on the unit shown in the picture may very well not even be a variable resistor (rheostat or potentiometer). Instead it may directly make a mechanical adjustment to a bi-metallic thermal switch. Jun 26, 2016 at 9:30

From GE Appliances Customer Service:

There is no specific correlating temperature for each number setting. The TEMP control determines the compressor run time. The higher the number, the more the compressor will run to create a cooler room temperature.

• So, it doesn't have a feedback loop?
– Neil
Aug 12, 2022 at 7:11