Use the Sun forFree Heat. 

That bright orb in the sky should be a focus of temperature control in your residence throughout the year.

During winter days, open the curtains on your south-facing windows to bring free heat into your home. Close your window coverings when the sun goes down to keep more of the heat inside.  This technique uses what is called “passive solar” because no energy is used to produce the heat. 

The winter sun does significantly less bleaching of rugs or other fabrics due to the lesser intensity of the sunlight than is present in the summer months.