Trachycarpus fortunei is hardy to about zone 7b. I am in zone 7a/New Jersey. So, in an average year they will be okay unprotected next to the house. In 6b they are even riskier unless protected. Your objective is to keep excessive moisture out of the crown in the winter. You can buy various kinds of frost cloths or burlap it. You could also put some holiday lights under the cloth but be careful..., you don't want to COOK IT. Some of those lights (even the tiny ones) can get very hot, you'd be surprised! The good news, is that the BIGGER the palm is/becomes, the cold hardier it becomes..., so size matters! In an AVERAGE year you should be okay..., but those winters of arctic vortices took a toll for me and I lost a few unprotected ones. Last winter my "big boy" windmill (Japanese fan/Trachycarpus f.) sailed through a mild winter just fine. My winters are very unpredictable though and can range from subarctic to subtropical so my palms live on the edge of survivability. You might want to also consider some Sabal minors..., especially Sabal minor Louisiana. They are cold hardier than a Trachycarpus and all of mine came through even the worst winters unprotected. Buena suerte!

Love you guys for trying.Good luck.Agree with jurasico.Would like to hear about progress.

Thank you for the advice. I will for sure take care of them. I will post some pictures here soon about any progress.

What temperature is usually the point where you start to protect them?

Not so much a specific minimum temperature as a sustained low temp. If sustained low temps are in the 30's, I'd be concerned. That may sound cold but it's NOT for a LOT of other non-tropical species of Phoenix. My Canary Palms regularly survive nights in the 30's in mid winter without any problem; Dwarf Pygmy is just much more tropical a species (there're from Southeast Asia after all).