My 15 year old heat pump runs continually, but if I turn it to emergency heat it runs a lot less, plus there is heat coming out of the vents. It seems to me it would be cheaper to run in emergency mode. It seems to run A lot less (blower). Can someone tell me if it saves money in emergency mode, and what is the cost difference?

You will save no money in the emergency mode if your heat pump is running correctly.

Long heat pump run times should only happen when it is very cold outside. A heat pump might have a hard time to keep up when the temps get below 30 degrees F.

Emergency heat mode is strait electric usage
Heat pump has added value from the compressor so it uses less electric.

That's great info. Just moved to a Ranch style house in Oregon. I guess I'd like to understand exactly 'how' the AC unit can run as a heat pump, and how it can be more efficient than 'Eheat' since it produces no heat of its own (AC that is.) thanks for the knowledge. Bob