At 66F,the bottles will def take a week or two longer to carb at least. Had that happen to me before. The Ambient temp def effects the metabolism of the yeast left in the bottles. So keep the container they're in wrapped in the blanket,it does help a couple of degrees,ime.
I keep my conditioning bottles & fermenter stand all in the same room as the computer. Been working well so far,give or take a couple degrees temperature.