Thermal backed curtains keep warm air and the heat of the sun out during the summer and keep the cold out and the warmth inside during the winter. They are an inexpensive way to lower your energy usage without much effort. Newer thermal curtains are attractive, with the thermal portion on the outside so it doesn't face into the room. Washing thermal backed curtains is not much different than other drapery care.
Vacuum the curtains on the front and the back to remove surface dust one to two times a month. Vacuum weekly if you open your windows in the summer.
Remove the curtains from the rods if they are too soiled for vacuuming to clean completely. Take off any removable hooks or hardware that are used to hang them.
Fill the sink with warm water and add 1/4 cup of mild liquid laundry detergent. Place the curtains into the water.
Gently agitate the curtains in the water with your hands, squeezing and releasing the fabric lightly. Avoid twisting or bunching the curtains as this can cause the backing to pull from the curtain front.
When finished, empty the sink and rinse the soapy water from the curtains with cold running water. Gently squeeze out the excess water and line dry before rehanging.