Do the peppers that survive outperform the new ones you start?

The pepper plants can last several years IF the winter is warm enough. They produce about the same every year.

I too have a short growing season. I built a frame that I cover with plastic in spring (so I can get them out a couple weeks before last frost) and fall so I can keep them out. I often do not have to harvest until December. I ran an extension cord and use my heating matts (for seed starting) and a soil cable (above soil). If temps go below 25 overnight I cover with a blanket too. This makes a world of difference for me getting ripe peppers. Any kind of cover that lets light in a a little heat goes a looong way. You can even use outlets that turn on and off at certain temps with a light bulb to add a little heat.

Agree with the comments posted. But I understand that in order to go dormant (yes, they go dormant, which means that they stop growing and won't fruit) it is best to leave them outside as long as possible. The chill triggers the dormancy. Keep them cool when indoors. You don't want them to break their dormancy until it is time to do so. It seems smart, with a short production season, to have mature plants as early as possible.

50 degrees is perfect overwinter temperature. I cut mine back to the first wye and for us in 9b all i do is if i see freezing temperatures coming grab my plankets and cover them! I would think a steady 50 is ideal. I watered about half way thru the winter and let my plants go dormant! Give it a try want you have to lose?

There is a lot written online about overwintering peppers. I see it written in various places that below 50F will stress the plants. Optimum temperature for dormant peppers is 55F. Reduce watering dramatically. Before bringing the plant in, spray it down to knock off any pests. The leaves WILL start to die back as it goes dormant. That's OK. Remove those. Coax out of dormancy by moving it to a warmer place a month before last frost. Water and watch for new growth.