Two totally different install methodologies right there.

What is coming out and what the two different installs?

You are covered on the windows. The 500 and 800 are fantastic.

You probably dont need new construction( nail flange) if there isnt alot of wood rot. The reason for a nail flange/ new construction would include removing all exterior and interior trim. If only using a nail flange and not removing interior trim, i see no point, a basic replacement would be just fine.
Both are great windows. Great pricing for the 800 series. Good luck.

This post was edited by mmarse1 on Tue, Apr 22, 14 at 9:05

Thanks both of you.
The contractor wanted to do new construction format said it's only available for 500, not for 800. He did mentioned about remove outside trim, but nothing about inside. and he only gave quotation on 500. The other guy said we don't need nailing flange and sent us quotes on both 500 and 800, which I mentioned before.

I agree with mmarse1, you probably don't need to go to the expense of replacing the trim to utilize the nailing fin. I'd go with the middle quote - 800 and retrofit installation.

You can, however, add a nailing flange (via clip in) to the 800 series.

I do agree that it is probably not necessary though.

Thanks. How much more do you think it will cost for the nailing fin for 800? Will the flange make big difference in energy efficiency?

Flanged install will be much more expensive but not because of the flange.

The install is much more labor intensive and if both are done correctly, there is no benefit in energy efficiency in one over the other.

+1. Great windows, and you probably dont need the full tear out installation. That is great pricing on all of the lines, particularly the 800 series.

Thanks to all of you. I will go with the 800 regular install. The guy has pretty good reputation on window installation through online search.

Great choice and good luck.