I bought a 1000 sqft roll to do one portion of my house that is always the hottest during the summer and coldest during the winter. I installed it myself, and took my time, as I am 45 and had a heartattack 2 yrs ago, plus the excessive heat here in texas in Sept. After 2 seperate saturdays (about 4 hours each day)crawling throught the attic and stapleing to the rafters I had it complete. The following Sunday I was working in my Garage sweating in the heat, and relized I had left a couple of tools up in the attic where I had put up the foil. I got out the latter and opened the attick crawl space getting inside,to my ammazement it was now actually cooler than in my garage, with my large overhead garage door open and side door open for ventilation through the garage, the attic was cooler. WOW this made a believer out of me. My wife also stated that during the days while she is home that the A/C comes on less and actually doesn't come on until almost noon now in the mornings. This product works very, very well. The price for 1000 ft roll is nothing compared to the cost savings and the coverage. I am waiting to see how the winter goes, since this was also the coldest part of the house. I recommend this product and will be buying more for the other portion of the house. and over my garage.