How to Make Thermal Curtains

Wanda Brito

Thermal curtains help seal off your windows to help keep a room’s temperature consistent without changing the thermostat. In the summer the room will stay cooler, while in the winter cold winds will stay out, keeping the room more comfortable as well.

Just what makes thermal curtains work? The key is in the lining. This type of curtain is lined with a special fabric that seals off a window so the room temperature remains more consistent without having to waste energy. There are a variety of insulation materials that can be used to make thermal curtains. Some are very thick with a rubbery texture. These are very durable and washable. They are not your only option, however. There are different fabric weights available for insulation. Depending on the climate control you need, you can choose a light or heavy insulation material. There are materials that offer the benefits of insulation in a much more appealing fabric. There are even color choices that will enhance the top, decorative fabric.

Energy costs can be reduced substantially through the layering effect of thermal drapes. The front layer of fabric in thermal curtains is the ornamental one while the lining is the functional layer. This front layer can be made of just about any medium to heavyweight fabric. This layer will not only add to the thermal function but also to the presentation. Thermal curtains made with a lightweight fabric that is too sheer, will not really hide the functional lining adequately. That is the main limitation in fabric choices for thermal curtains.

Thermal curtains are fairly simple to make. It does take a small amount of ability to sew and measure. The instructions that follow should help you save money by making your own thermal curtains.

  1. Measure the height and width of the windows you are making the thermal curtains for. Keep in mind that your curtains should extend beyond the window for best results. In addition, give an inch or two allowance around the perimeter of the fabric.

  2. Cut the insulation material and the fabric according to the guidelines in Step 1.

  3. Pin the fabric to the insulation material (with the outer surfaces facing in) in order to facilitate the sewing.

  4. Using a sewing machine, sew the fabric to the insulation material. Sew three of the edges together and then turn the inside out to expose the exterior. On the unsewn edge, tuck the inch or two of allowance material into the curtain and sew closed.

  5. Make holes in the curtain about ¾ inch from the edge along the top to put the grommets into. Holes should be an equal distance from each other. Hammer the grommets into place.

  6. Sew Velcro along the sides of the curtain that will be adhered onto the wall. Position and affix the other side of the Velcro on the walls in the corresponding position of the Velcro on the curtains. This makes for better insulation.

  7. Install the curtain rod and hang up the curtains.


North-facing windows in the Northern Hemisphere allow the most heat to escape in the winter, while south-facing windows get lots of sun all day; so you may want insulation on these during the summer. Be sure to use a sturdy material that is not going to stretch or rip easily. Twill is a good material to use. Use recycled or sustainable material and you will benefit the environment in more ways than one.


Lined curtains should be dry-cleaned; fabric and lining can shrink at different rates if they are washed.