Keep your house cooler by putting trash bags on sliding doors when it is hot and sunny outside. My sliding door lets a huge amount of sun and heat in in the morning. I use those large black yard waste trash bags to block the sun and heat. Painters tape will hold the bag. I only need two pieces at the top.
When the area is shady I just take the bag down and fold it up to reuse. I stick the painters tape to the sides of the door frame and reuse it also. I am sure it would work the same if you get evening sunlight. Standing outside on a sunny day, you can't even tell it is there.By ann from Saint Peters, MO
They make reflective plastic that is just for patio doors. It is not expensive and reflects all heat. It looks like a mirror from the outside but you can see out from the inside. Much better than garbage bags.
Great Idea, but, at Walmart in the camping area, is a light weight blanket that is made of some type of NASA material. It is like the size of a deck of cards, costs about $2.00. and I put it on windows and you can hold your hand up to it and it keeps the inside cool. You can also see through it, so, it stays in place and don't have to guess on what's on the other side of that door.
We had a house in FL with a very large family room, thus very large windows & patio doors. I bought Window Tint at Home Depot by the roll. It's like what they tint car windows with.