Hey everybody I\'m trying to improve the performance of my vintage metal Coleman cooler I just got. To test it I filled it up with water bottles and 5lbs of cubed ice from Stop and Shop and left it in the closet with the dorm\'s AC set to 65. When I got back 28 hours later the ice was completely melted. The water still kept the drinks cool for several days after that, but I\'m frustrated that the ice melted in a single day.Aluminum foil has zero R factor (insulation factor). However, if it put on the outside of a cooler it will reflect the sun rays away from the cooler, and make it easier for your cooler to keep things cool. Gel packs are slightly better than extra ice (depending on the amount/concentration of glycol alcohol in them) -- gel packs are popular because they are self contained and not as wet and messy as melted ice. Edit: Well, indoors the aluminum would not be a complete waist. Heat waves from inside the house would still bounce off the aluminum. But the other answerer mentioned a very good way to further insulate your cooler. Just attach (tape or glue) stryrofoam sheets to the outside of your cooler == that would be a big time improvement.It\'s perfect if you are just starting out or if you\'re a seasoned carpenter. you will like it for sure ! It has almost 20.000 woodworking plans and you have a CAD/DWG software to view and edit the plans. You have step-by-step instructions with photos and high quality blueprints and schematics. If you are a beginner this is the easiest way to start your woodworking projects, and if you already have experience you can anyway find a lot of interesting ideas!installing styro foam sheet cut to size glued to the exterior and then take the same product 1/2 thick and apply to inside will greatly improve your preservation time.also throwing a old folded blanket around the out side worksOther related question