Will an "outdated" round thermostat work with a new air conditioner?

Get into a time machine and return to the past.

You need someone (electrician, guy who installed the AC) to explain how to use the thermostats. There is probably useful info in the manual, also. I know that they are not fun to read.

(Egypt is not a galaxy. And Egyptians probably feel equally put upon when they buy appliances with instructions in English.)

I said OR another galaxy. They did not come with a manual. Have a nice day.

Honeywell still makes “The Round” – classic thermostat – that should work just fine. Thermostats are basically just switches, so there aren’t too many compatibility issues.

It should work. There are new ones that are not digital still. There should be a manual for yours, most likely it is online. Most digitals have 2 or 4 time possibilites for automatic change temperatures. You can just set all the times at the same temp and never have to deal with it again. You will still be able to put it up or down to click it on or off at whim. If you tell us the brand I can maybe you help you with it. But, if you want the old style, it’s probably not very expensive.

@Aster DAo you have a model number of the thermostat? Maybe the manual for that can be found online and we can attempt to decipher the mysterious glyphs collectively.
[ p.s. “Egypt or another galaxy” Seemed clear enough to me. I did not confuse Egypt with a galaxy. ]

Me too Egypt as in BFE. LOL.

The “round” thermostat must be matched-up to the A/C and have both the “A/C” position switch and the “Heat” position. Does the round one, you have, have places on the back for six to eight wires from the new A/C ?

@Tropical_Willie I don’t know what’s on the back and we won’t be checking!! I’d just love to have a non programmable analog one. They were always so simple to operate.

You might also take a look at the new, rather pricey Nest intelligent thermostat, which has been lauded for its intuitive user interface. Its design is inspired by the classic round device.

THis is a really good time to say “It depends”. There are a number of questions that you need to address:

1) did you have an AC before? Or is this a totally new one? If you had an AC before, then you had 4–5 wires that the round thermostat controlled. IF you didn’t, then your electronics are *totally * different and the old one won’t work.

2) How many wires are connected in the old one? (Similar question to above)

The answer is really MAYBE. It depends on the layout.

(By the way, although they are more complex, the thermostats with internal timers are really a good thing and I recommend them.)

@Aster Call the person / company that installed the new A/C. The fact that you don’t want to look at the back for wires, tells me you need to have a professional do the installation.

I agree with @Tropical_Willie just give the company a call, or send an email, that did the original installation.

I don’t see how it could work, if it is just a furnace thermostat. I have to switch mine from heat to cold, and I don’t imagine the old round thermostat would have that capability.

@Skaggfacemutt yes, the old Honeywell thermostats had “cool” and “heat” on the dial plus the temp you wanted. You can see a photo of Honeywell analog thermostats on www.google.com .

@Aster The round thermostats will NOT work with a heat pump / auxiliary heat type A/C. I just verified it with the spec sheet for Honeywell YCT87N1006 The Round Heat/Cool Manual Thermostat.

@Aster Here is something new on the market, it is called the Nest. Might work for you should be professionally installed ? ?