I have had some issues with temperature in my fermentation operation as well. Sure it is beer rather than kefir but 68-71 degrees is what it is. Just takes a little longer for the yeast to do what it is to do and a little space heater during the prime fermentation phase. Actually loving the post fermentation phase with lower temperatures slowing bacteria formation.

Fermentors will be in high demand for the post-apocalyptic communes! ;)