Each window company designs their window and initially they all will do the job. The spacing of the panes is not as critical as the quality of construction by the manufacturer. If you are choosing replacement windows, just my opinion, it really will not matter too much since they all will fail somewhere in the not too distant future. In windows you really do get what you pay for.

Thanks for your words of encouragement, but I'm not sure what you are suggesting - keep my old non-functional, rusted, leaky windows or spend as much money as possible on replacements? I don't have an unlimited budget and I am simply trying to balance the costs and benefits of the various products available.

I would appreciate any CONSTRUCTIVE comments.

What I was trying to explain was that I am not a great believer in replacement windows that are manufactured by a variety of companies. Living in Florida you are not subject to the extreme cold that we have in the north and the high heating bills. I only know from experience the problem that many people have had with these types of windows. While initially they work quite well, within 5 to 10 years the complaints begin of leaking air and condensation on glass. I am sure some people have had good luck with replacement windows, but from my experiences they are the minority.

For the above reasons I would not even consider installing them and tell people to look for another contractor. I will spend the extra money and purchase windows that have stood the test of time. I have no qualms installing a quality product from Anderson, Pella, etc. I know for a fact that 15 or 20 years down the road these windows will still be doing their job and the bad complaints are the minority. This was all that I meant by "with windows you get what you pay for". All of the talk that you receive from salesman about pane spacing and other words is just their way of trying to overwhelm and confuse you. In their world the best salesman wins.

If you have time, write to the above companies and ask for their specification and test data sheets and compare their results to the companies that you are speaking with now. You will receive straight facts from them. You can then make an informed and intelligent choice. It is a major expenditure and not a decision that you want to end up regretting.