A 15 gallon Sabal minor or Rhapidophyllum hystrix would be much hardier. The only time the Windmill palm (Trachycarpus fortunei) becomes hardier than the the previous two is when the growing season is too short and cool to produce enough energy to overwinter year after year. Windmills can recover in less time with less heat.

Thanks im going to check those out any info on where to get them?

Where are you located?