It came down to the second two companies which prices were within $1000 of eachother. Company 2 used triple pane glass that had a better insulation quality, the windows had no metal pieces, they stiffened the windows with extruded fiberglass, and the installer was going to finish all the wood work. The sales rep also talked extensively about how good the install was and had pictures of his work. Normally they used cellulose insulation but I asked for spray foam and they were willing for no extra charge.
Company 3 had double panel glass, and said it was just as good as triple pane but then it had a lower insulation rating (so that didn't make sense in terms of actual numbers...) then they told me that the sashes were stiff enough because they use virgin plastic. Now the cross section of the sash was very strong but to me it looked like that was based more on the extrusion shape and not the actual material. So as an engineer I didn't really respect their technical knowledge or at least the information they were giving me. They also weren't going to finish the inside work so I would have to stain and varnish all of it, which I am capable of but wasn't looking forward. They always used spray foam.
Companies 2 and 3 both got out the heat lamp test to prove that their windows don't let heat in or out. They both had a life time warranty on the windows as long I live there, and a transferable warranty of different lengths- which will be nice for the new owners when I sell the house.
The choice came down to three aspects:
Better insulation
Finished wood work/ Confidence in the installer
a longer transferable warranty
I went with Windows Depot. The lead time on the windows was longer than the original quote. But my dad has been so impressed with the install it is worth it. And dad got to be around when they were being installed, I had to go to work, so he definitely has a better picture of the work.














