Installing "ecobee3 Lite" Smart WIFI thermostat
 

For those considering upgrading their existing "Carrier Edge" thermostat.
After research, I chose the ecobee3 Lite. $169 at Amazon.

I discovered that my existing original (6 year old) Carrier Edge thermostat for my Carrier heat pump was wired with only two wires to an interface control board which is mounted on the outside of the air handler in the garage. What I thought was going to be a problem, was not.

The two wires from thermostat connect directly to the interface control board along with the other necessary wires for a smart thermostat, except for a required common "C"wire.

The cable between the thermostat and interface board contained 5 wires. (3 are spare) Exactly what is needed.

The ecobee thermostat comes with an adapter included called a "PEK" that provides the C wire. It is connected along with the other wires using wire nuts on the outside of the air handler. No need to even open the cabinet.
The interface control board that is mounted on the side of the air handler is completely bypassed and can be removed.

The ecobee is better than expected and all functions including emergency heat still work.
The reports online even show in graph form, when (and how long) air conditioning, heat, emergency heat and fan were on. Along with humidity levels.

I installed the newest Nest thermostat last month, replacing the Carrier Edge. Can't believe that HVAC vendors charge $175+ to do it, it took literally 20 minutes.

Which model did Nest t-stat did you install?

This is such a coincidence! We are now in the process and confused because ours has 6 wires and instructions show 4. We have a standard builder AC. Is that considered a heat pump? Our home is 12 yo. As you can tell, we know nothing about this. We’re ready to give up.

Not sure which one Laboutj installed but we recently installed the Nest3. I had seriously looked at the Ecobee3 lite but my wife has used the Nest in the past so rather than confuse her we went with the Nest.

I hate my Ecobee and having to navigate through menus to turn off or on the HVAC. I miss my old thermostat with the select lever below (Heat-Cool-Off) and one temp set for all with no buffer zone.

Do you have the app on your phone or the website on your computer???
Simple, Simple, Simple.

I installed this one: https://www.homedepot.com/p/Google-N...4-US/314573006

I don't like it as much as the more expensive 3rd Gen. I got a deal on it that I couldn't pass up from the electric company in the state where our other home is. It's easier to control from the phone than trying to change temps on the thermostat itself.

I can post separately how I hooked it up, but I actually found the links using the search function on the forums.

Is it a Carrier unit? What kind of existing thermostat do you have?

When you download the app it will walk you through how to hook it up. The app asks you which color wires you have. Have you gotten that far?