I just purchased and installed the 8500 series in my home in NH. They were a snap to install and are great looking and work great too.I spent $700 for oil last year and I'm eager to see the savings from the install of these windows.. I did alot of r&r befor my purchase and spent $1600 for 10 windows. I was quoted by 2 other window companys from $5500.00 to $8000.00.