The argument that one spacer system is inherently superior to another or all others  is ripe with the possibility of misinformation, misunderstanding, and certainly a great deal of emotionalism. Each system has its proponents and its detractors. SuperSpacer uses an organic as the primary moisture and gas seal. It uses an acrylic as the primary structural seal. Unlike other systems, SS is "backwards" in that it places the structural seal inside of the moisture seal. The primary structural component of SuperSpacer is silicone - which is neither moisture nor vapor resistant, so the silicone is wrapped with a moisture barrier to prevent air and other gasses from passing thru the silicone. Does this make SS an inferior product? Nope, not in the leastÂactually SS outperforms every other system on the market in energy performance numbers. What EdgeTech (makers of SS) does really well is market their product (for example "Health Smart Windows" is primarily a marketing tool). They have what may be an excellent product, but they also have a marketing program that totally kicks butt! They have opened areas of discussion that really didnÂt exist prior to their introduction of itÂthey have emphasized SSÂs inherent advantages while ignoring any potential disadvantages (which is what marketing folks do, of course). They have "invented" new ways to categorize window spacer systemsÂheck, they have introduced IGU spacers to the general public. For an example of longevity, EdgeTech advertises that their system goes 80+ weeks in a P1 test chamber (a standard for testing dual pane windows). They advertise that the "Stainless Steel" systems go 40+ weeks in the P1 chamber. What they donÂt advertise is exactly how long is the "plus" in the 40+ weeks of the "metallic" systemsÂhow about 80 weeks for a PIB / silicone dual seal stainless steel spacer system. By the way, at 80 weeks or so the glass begins to break down and the seal tends to be lost at that point because of glass rather than spacer issues. The hot melt systems used with the SuperSpacer system also have a very specific application temperature range of about 275º  325º. If the applied material is outside of this range, then the P1 chamber testing can be significantly reduced  to as little as two to three weeks to seal failure. What happens in the field in this case? Only time will tell. Am I slamming SuperSpacer? Nope, not a bit. When manufactured to strict quality control standards and exactly as specified by the manufacturer, then SuperSpacer really is a very good, even superior, product. Energy performance and durability are what these things are ultimately about. How do different systems compare? As I mentioned, SuperSpacer is on top  at the edgeÂand TPS is second, by about ½ of a degree or so. The Stainless Steel systems (there are a couple of different ones) tend to be about a degree or so lower  about equal to Swiggle (again, at the edgeÂthe difference may not have much of an impact on the overall U value depending on the construction of the window). Drop another degree or so to Intercept and about another 8º for an aluminum spacer. Using a LowE coating will have more of an effect on the overall window temperature than does the choice of one of the "warm edge" systems. Of course using a LowE coating with SuperSpacer and with Swiggle still keeps SS a couple of degrees warmer at the edge. BUT, these are also ratings of the "raw" IGUÂwhat happens when the unit is in a frame? Well, how about this for thought: Conclusion The thermal resistance of the spacer bar material influences the glass temperature at the edge-of-glass region of an IG unit. Based on the limited testing performed at IRC and computer modelling at EMPA Switzerland, the spacer bar with the highest thermal resistance shows the warmest glass temperature on the warm side and the coldest temperature on the cold side of the glass at a distance 5 to 60 mm from the edge of the IG unit. But the effect of the type of spacer bar on the overall thermal resistance (and tote heat loss) through windows depends heavily on the window design and material. Therefore, the full impact of thermal characteristics of the spacer bar material on the thermal resistance and the condensation resistance of a window should only be determined by testing complete window assemblies. Interesting concept  testing complete systems.

This is my same post to a blog from a few days ago, but answer applies here. Let us know who you go with! I got new windows installed over the last few months. I wanted fiberglass, brown on both sides. I got quotes on Anderson Fibrex, Milgard Ultra, Marvin and Pella. As stated above, Anderson's Fibrex is NOT fiberglass. When I asked if any vinyl was in the product the sales rep stopped replying to me. I lost faith in Marvin because the sales rep here tried to sell me windows with argon in order to qualify for the tax credit, but failed to tell me their warranty is VOIDED if windows installed at over 5000ft don't have breather/capillary tubes because the seals can pop and glass bows. http://search.yahoo.com/r/_ylt=A0oG78xF119NszsANUdXNyoA;_ylu=X3oDMTBybnZlZnRlBHNlYwNzcgRwb3MDMQRjb2xvA2FjMgR2dGlkAw--/SIG=129s3ps6l/EXP=1298155461/**http%3a//www.marvin.com/download.aspx%3fDocumentID=1547 I ended up going with Milgard. Over the warranty was the best, the product has great ratings, and it was pretty cheap to get triple pane. You can read my blogs here of problems I have had though, but it is not with the product itself. Between the sales rep and the company they have made FOUR mistakes on my order from the wrong size to missing grids to non-matching grid patterns. They were supposed to be done with installation in Nov, and it probably won't all be fixed until March. I still like the product though. Out of the 4 quotes, Marvin was the most, Anderson was 2nd most expensive.

Thank you Toddimn and EcoStarRemodel. Toddimn, thanks for the warning about the need to install a header if we combine the windows. We'll definitely look into what is involved before deciding if we want to go that route. I went to another window store that had a better variety of display windows. They carry only Milgard. Milgard seems to have the corner on the market in this area. After seeing the both the Style Line and Tuscany windows, I would definitely choose Tuscany. The Style line have thin, unimpressive frames and look very similar to our aluminum windows. The Tuscany frames are much beefier, more like a wood window. The uneven sight lines in the Style Line windows doesn't look good to me. The operable windows have glass that is at least 2" smaller, whereas the Tuscany windows have matching glass sizes. The Tuscany locks are nicer and the weepholes are covered. Montecito is the same frame as the Tuscany. The Montecito lacks a few of the nicer features of the Tuscany and doesn't have the glass breakage warranty. The saleslady told me that the price of the two lines is almost the same ( usually within $2 to $5) so she doesn't ever sell the Montecito. Home Depot gave me a quote for Montecito windows. That might be one good reason to buy from a window supplier rather than Home Depot. Neither window store that I visited had any double hung window displays. I would be interested to see one. I was told that the double hung windows have thicker frames than the single hung. I don't think I would want an even thicker frame for our narrow kitchen windows so the double hung might not work for our home. I guess the single hung could look mismatched since the screen is only on the bottom but I wonder if it would be annoying to have to look out a screen at the top? I will do the contoured grids just in the top of the windows. They don't come in a smaller size. EcoStarRemodel, the window salesperson said that they can order picture windows with frames to match casement windows. She suggested making the two center windows into one picture window and putting casements on the sides. That way the view in the middle wouldn't be obstructed by the center bar of a double casement. However, she said that the picture window in a casement frame would cost almost as much as a casement window. I didn't realize that all of the windows in the house should be of the same type If that's the case, then I wouldn't want to go with casements. We would need 13 of them which would be way too much $$$. Would it also look weird if we combined the two center kitchen windows into a picture window with single hungs on all the other windows?

Yes, they are installing all the windows and the front door. My contractor, who is the one that referred them to me, said they would charge a lot to install the sliders cause you have to cut into the stucco. Since he is working with us on various projects, including replacing some facia board before we paint, he said he would do it. I have to call her today and let her know which hardware we want as well. She gave me the Emtek catalog and they have some amazing prices! I will let you know and post pics! Toodlse, L