Your cool place should not get under 36 degrees or else it's a goner!
Pelargoniums are succulents! When I lived in Germany, we would take all the
dirt off the plants, hang them upside down in the root cellar part of the
house. By early March we would start potting them up giving them water and
florescent lighting. Gradually we got them outside and enjoyed them for the
rest of the spring and summer months, then cuttings were made and by the
Octoberfest time...we would start getting them ready for winter again!