[rwest]

A heat pump will be more energy efficient than a standard AC unit- but, using it to heat may be more expensive than using natural gas as most places electricity is more expensive than gas.

In your situation, we would need more information on what you have now and what is being purposed.

In my house, using a conventional gas furnace with a AC coil is my most cost effective option- I live in MN, so winter heating is substantial.

In my garage, I was using an electric heater to keep it around 50 degrees in the winter, but I replaced that with a mini split unit that is a heat pump system and it cut my cost considerably.