If they are the same model, they are the same window (assuming the options are the same).

I would deal with a building supply house first before a big box store. The guys at those counters tend to know their stuff a bit better and you will get just as good a price.

I agree. Some lumber companies also supply windows. If you are just having them installed then go with a GC that can get the window you want. Dealers will mark them up up to 3 times before you ever see a price and that's a fact well known. If you go with a good GC he will warranty your window for 15 years himself on top of the manufacturers warranty anyways. As for windows first decide what you are looking for.. either wood or painted. In my opinion the best is Fiberglass through these manufacturers: Accurate Dorwin, Fibertec, and Thermotech. Serious windows use to be best but Alpen windows in Colorado bought them. Last would be Marvin infinity but they are sometimes higher bid. Canada the best windows for some reason.. maybe they have higher standards than the U.S. Good luck!

Wow...there is a ton of information in this last post and I don't mean to be combative, but most of it is wrong.

Dealers will not mark up your windows at 3X as a standard. There is no set rule and most manufacturers do not allow dealers to sell product only. Most require they sell as an installed service so as to control the installed product quality and therefore maintain the reputation of the product.

Most new construction builds do not have the attention to setting the windows as you would find by a window specific dealer/installer and the last thing that a quality manufacturer wants is to have their windows not perform as a result of poor installation.

The fact of the matter is that should you find a dealer that will sell direct, there will be a mark up in the product, however, to claim that all will be at 300% is false. Some could be higher for that matter but most will be lower.

I would love to see the GC that you are referring to that offers a 15 year supplemental warranty. The standard warrant on most new construction builds is 1 year when it comes to windows. If you are talking about a custom builder, they may go a bit beyond that but I have never seen one go out to 15 years longer than the manufacturer. How would that even be possible on a 20 year warranty? You are going to call the builder of the home 34 years and 364 days later and ask them to fix a window?

When was Serious windows the best? You do realize that they don't produce their own fiberglass and were basing their window on another company's pultrusion. Serious was a fantastic marketing company but did not make anything at the level of those other manufacturers that you mentioned.

We decided on Marvin windows, not available through HD or Lowes, so it's probably a dealer. Our GC budgeted $40,000 for windows and recommended a specific dealer for our Marvin Integrity triple-pane windows. The window schedule has gone through several iterations with a few deletions and additions; the final quote was about $26,000 for 30 windows (mostly 30 x 60 casements) ; this schedule was sent to the GC, and his estimate didn't change. So, should I assume that if he gets the windows from this source, he will get a contractor discount, and will make his money for the install from the difference? The dealer would like to install them themselves, but accepts the likelihood that the GC will install them, and will still honor the warrenty.

We sent the window schedule to another dealer for a quote on Loewens, but haven't received it yet. After a week, they got back to me and asked for my ship-to address. Loewen is Canadian, and they have better u-values (.15 vs .20), but I know nothing about the air infiltration values for either brand. .

All the casements should be super tight either way.

Good selection and well done.