The central a/c in my house is on the fritz. When I turn it on, the emergency heat comes on and blows out warm

air. Any suggestions as to what could be wrong? The central heat is working fine, just the a/c is not acting right.

The central a/c in my house is on the fritz. When I turn it on, the emergency heat comes on and blows out warm
I don't know where you live...but it's the middle of winter here in Tennessee. On most newer thermostats, there should be 4 settings...cool, heat, off, and emergency. You mentioned that the emergency heat is coming on, do you have it set on emergency? Sounds like it might be time for a replacement thermostat if you have it set to cool and the emergency heat is activated. You might want to have a certified HAVAC technician come out to your home for an inspection of your heating/cooling system. If you decide to change out the thermostat yourself, make sure you cut the power off to the heat pump. Failing to do this can seriously damage the circuit board in the HVAC. A friend of mine recently had to have the circuit board replaced in his because he failed to turn off the breakers to the heat pump.
Reply:You have a heat pump. The outdoor unit should run in the heat mode. For more info including a troubleshooting guide, check out the heat pump page at my source.
Reply:if your a/c and heat run at the same time, call your heating guy.
Reply:Sounds like the reversing valve is stuck in your heat pump. You'll need a HVAC tech. Sorry!