Should add - as for the energy efficiency questions, I'm in NYC.

The Okna 800 is a great window. Adding color to the exterior definitely adds more money.. Yes, if the gap is too narrow then caulk around window is fine.

Thanks mmarse!

I think I'm almost there, just haven't fully figured out whether I should get the triple pane windows or not. I've well exceeded my budget at this point, but I want to be absolutely sure I get the best windows I can at this price point and not just miss out because of 10-15% at the end.

I'm concerned because I've read in some places that triple pane with certain coatings can result in a loss of ambient light, something I don't want to do (especially since the glass area is reducing in size going from my existing windows to these).

Whether Triple Pane glass is a good option depends on the additional cost and where you live. Prices on TP have come down over the years and I expect they will continue to fall as more manufacturers get involved in the R-5 Window program. The problem in the past is that the additional investment in the necessary equipment to produce a TP window has been expensive and so manufacturers charged a premium rate. So whether it makes sense depends largely on how much more and how long you plan on living in the house.

While TP does produce a more energy efficient window, the trade off is that you will have a lower Solar Gain in the winter and also reduced Visible Light or VT. It may very well be that it makes more sense to use TP on the North, East and West elevations and then use Double Pane on the South.

Okna makes an excellent window as does Gorell. I would base my decision between the 2 on which company you think will do a better job. If you think the both will do great, then I would look at the aesthetics and the total cost.

I would also ask if they are using krypton or argon gas between the panes. Krypton is preferable but it also comes with a higher price tag. Savings % will vary depending on where you live but keep in mind that although the difference in energy efficiency between a TP with kyypton at a U-factor of .15 and a DP with argon at .29 is nearly 50%, that does NOT mean the window will reduce your heating and cooling costs by that much. Depending on where you live, I would not expect to see much more than approx 10%-15% difference in utility costs between the two.

Sky is 100% correct. I would always try to get the absolute most efficient window that I could get but there are several factors that bear consideration.

At a U-Factor of 0.26 of the Okna 800 Deluxe, that is very near where most of the triple pane argon numbers are for the Gorell.

I don't think the Krypton is worth the additional investment in most cases as there are other locations in the home that can be upgraded and have a much better ROI when you examine their impact on utilities.

You have a couple of really good windows up for comparison there and as long as you pick a good installer, you can't really go wrong. If I had to choose, I like the Okna 800 better for its better thermal, air, and structural numbers, but both are stellar windows.

Thanks skydawggy and WoW.

The installer part of the question is out of the equation - the same installer sells both Okna and Gorell, and they come recommended with generally good feedback on the Internet.

The pricing he gave me was close, with the Gorell 5300 coming to be about 10% more than the Okna 800. To be honest, I didn't see much of a difference between the two but little features like the locks intended to let you keep the windows slightly open for ventilation but still secured as well as the metal lift made the difference for me.

The figures I got were for triple pane, argon filled gas. The salesperson advised that krypton was a lot more expensive and didn't merit the extra cost (in terms of recouping investment over the lifetime of the windows).

I hate the light loss that the TP glass will provide (WoW was kind enough to provide me those figures on another forum, thanks again!), but I can live with it if it makes it easier to cool the house in the summer. The next upgrade to the house is a mini-split AC system, which I'm hoping together with the window upgrades and some insulation and painting on the roof will make a big dent in my heating/cooling bill over the next year.