How to use cardboard for room insulation

Updated December 21, 2016

If you have a room in your home that is always cold in the winter, it may need more room insulation. Insulating it with corrugated cardboard may sound like a cheap fix, but it's actually quite effective method of insulation. The best way to use cardboard room insulation is to cover windows and unused doorways with it. These two features are always major sources of heat loss. Corrugated cardboard room insulation may not be the most stylish room decor, but it's only a temporary fix and you can take it down as soon as spring arrives.

Close and lock the windows and doors that need cardboard room insulation. Put a layer of duct tape over the worst leaks to boost the insulating effects of the corrugated cardboard.

Measure the length and width of the window or door to determine how much cardboard you need. Find cardboard to cover the area. Two pieces of cardboard can make a difference, and three or four are even better if you can find them. Use a utility knife to cut the pieces of cardboard to the dimension of the window or door.

Place a bead of glue on one side of a piece of cardboard. Lay a second piece of cardboard on top of it. Align the edges. Repeat with the third and fourth piece of cardboard if you are using them.

Tape the edges of the cardboard stack closed with duct tape. To increase its resistance to heat flow, cover the entire piece of cardboard with aluminium foil. The foil helps radiate heat from the room back into the room.

Tack the cardboard piece in place in the window. If you prefer, you can use tape to secure it in position.


Look for corrugated cardboard with thick baffles. The thicker the cardboard, the more insulating properties it has. Appliance stores are a good source of thick cardboard suitable for this project. They're usually happy to give the cardboard away. If you can't find enough cardboard, sandwich a layer of bubble wrap between two corrugated cardboard pieces. If the cardboard is too unsightly for your taste, cover it with curtains or tape some artwork to the foil.


Flat cardboard doesn't provide the insulating effects of corrugated cardboard.

Things You'll Need

  • Duct tape
  • Tape measure
  • Corrugated cardboard
  • Utility knife
  • Craft glue
  • Aluminium foil
  • Tacks
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About the Author

Denise Brown is an education professional who wanted to try something different. Two years and more than 500 articles later, she's enjoying her freelance writing experience for online resources such as and other online information sites. Brown holds a master's degree in history education from Truman State University.