I just replaced an old heavy wood door with a metal door, 9'x7'. That wooden one was heavy, but I could lift it without the springs. Had windows 3/4 the way up.
I bought mine at Home Depot. I DO NOT recommend this route for those looking to replace or upgrade. They charged me $550 delivery included which I thought was a good deal, until I read the receipt from the door co. that delivered it: $222!!!
I complained to HD, but basically said take a hike. So I did ....... straight to Lowe's & I've never been happier!
While installing the new one, one of the cables let go (I didn't have it looped correctly) & fired the spring like a missle. I was about 10 feet away, but luckily adjusting the other spring ... so out of the line of fire!!
What a sound that made! I think the neighbors heard me yell WTF at the top of my lungs from inside!