Hi, I'm looking to replace my thermostat with a new programmable one, and I'm trying to figure out which ones might be compatible with my heat pump. I'm having trouble determining even what type of heat pump I have. Any help would be appreciated!

Here is the information I have:

On the unit outside:
BDP / Carrier
Product #: 542EBX042000AAAF
Model #: 542EB042

On the existing thermostat inside:
Payne Heat Pump
BDP Co
34427DP120
3AAB82B14C2

Wiring:
8 wires
C: Black wire
R: Red wire
O: Orange wire
G: Purple wire
Y: Yellow wire
W1: White wire
W2: Brown wire
E: Blue wire

I believe the unit was installed in the early 1980s. Please help!

Do I have a single or multi stage heat pump?
What do the wire colors mean?
What type of programmable thermostat should I be looking for?

Sorry for the lengthy post, just wanted to include all information. Thank you for your help.

You have a two stage heat one stage cool unit. First stage heat is heat pump second stage is resistant heat.The wiring colors will be explained in your new thermostats install instructions. Honeywell makes a good thermostat. Please read the entire manual that comes with your thermostat. If that fails you then look to the sticky notes at the beginning of this board.

I disagree, it appears you have a three stage heat, the first stage is the heat pump which is the orange wire that reverses the reversing valve, the W-1 is aux. (electric heat strip), the W-2 is another aux. heat strip, that makes three stages of heat.
The second heat strip may be connected to an outside thermostat to keep it from operating until the temperature drops to a preset temperature, this saves money.
The "G" is to engage the indoor fan, the "Y" is to bring on the compressor, the "C" is the common from the transformer to operate a clock or lites in the thermostat, the red "R" is from the transformer (a different leg from the "C") this is switched by the thermostat to the G, Y,W-1,O, W-2, depending on what is desired by the operator.
The "E" is emergency heat and when switched on it disables the heat pump and only enables the aux. heat.

Thank you both for your answers. Is there any further information I can provide that would give me a definitive answer? I have pictures of the thermostat, and of the wiring diagram from the inside of the cover of the heat pump unit if either would help.

Thanks again for your time.

What does it mean if my yellow wire in wrapped on both the Y peg and the W1 peg?