Disclaimer: I'm a first time homeowner, and have only been living in the house for less than 6 months. Please bear with me as I learn!

The house is about 28 years old in the Northern Delaware area. It is an all electric heat pump (forced air) system, with the furnace and a/c are almost 2 years old.

Inside the house is a Trane XR402 Comfort Control. It has heat and emergency heat (emheat). So my main question is when should I use heat vs. emheat? I vaugly remember someone trying to explain to me that I should use the emheat when it got very cold, or something like that. But I wanted to post here to see what more specific advice I could get.

Thanks in advance!