Do heat pumps have heating elements?
My thermastat is set for 68 degrees but when I got up in the middle of the night is was cold to me so I checked the thermastat and even though it was set at 68 before I went to bed the actual only said 57. It is running but not getting up to the temperatur the thermastat is set at. I have using enmergency heat when I go to bed.

Heat pumps are only efficient down to a certain outside temprature.

You might be referring to what's known as emergency or Auxiliary heat, which might usually be electric (but could be gas or something else) but installed on your indoor portion of the home Heating Cooling unit.

What were the outdoor tempratures the night you mentioned?

Do heat pumps have heating elements? No

What is the outside temp? What kind of emergency heat do you have? Gas-oil-electric? Is it working ?

Lots more info is needed

The outside temperature is about high 30's at night. I have electric heat for the emergency heat. Yes, it works when I turn it on. I have just heard though it costs more to heat the house that way. It is mid 40's during the day.
This is the answers to my previous post.
catwoman57

I have just heard though it costs more to heat the house that way. it is mid 40's during the day.

You have a choice. Pay for the electric to keep warm or be cold. Heat pumps as mentioned before only work well to a given temperature so you will have to use the emergency/resistance heat to keep warm when colder temperatures hit. In most areas it is a bit warmer during the day than at night.

Keep the filters clean more so if you have indoor pets, make sure all vents (return and supply ) are clear and open, you might look at improving the house heat lose,around windows and doors, set tstat a couple- three degrees lower will help on the operating expense

We all have to pay through the nose to keep comfy

The 30's is about the limit on a system in top tune.

When was the unit last serviced? Is the pump running constantly? Is there icing on the indoor evaporator/condensor unit (if its running constantly its highly possible it is)? I'd look for that... If it goes on and off all night (but not frequently) then its likely working fine, and just too cold outside.

If you can say yes on the last two questions... the freon is low (or the pump is worn out) and the system isn't cycling long enough to eliminate that from happening. And you need to call for a service.