Oh Auntie Em, no wonder you fear the cold, all that latino blood running through you!
Anyway, about this cold cold winter in the CB, or CDS...........a good tip is toleave the sun blinds open all day, trapping the heat, then close them before the sun goes down. This is quite effective.
Also, here in the Torreveija area, Some people have had this film put on their windows, is mirrored from the outside, so no blinds needed, but you can see out from inside. It keeps the house cool in summer and warm in winter.
My neighbours have it and said they didn't use ANY heating last winter.
We are Playa Flamenca and face the sea, so get the cold winds straight at us in the winter.
Not sure if the window film would suit everyone, don't think I like the look of it personally, but cheap to install 300€ for a wide balcony (set of 6 windows).
Rgds,