Both are highly reliable and efficient. I'd pay a slight premium for a non metallic spacer like super spacer or duralite, but the stainless xl is good. Either would be a major upgrade over the standard intercept.
Reliability: equal. Performance : slight advantage to super spacer.

XL Edge is what is known as a " true stainless steel" spacer. Many spacer's such as intercept are tin plated steel and NOT stainless. Remember, stainless steel is less conductive than its tin plated counterpart ( intercept).

I am in the same boat as the other guys.

Both are great and I wouldn't choose one window over another based on that fact alone.

Glass and spacer prep are going to be more important at the end of the day.

I have seen more issues with Super Spacer than XL Edge from a purely numerical observation.

WOW's observations are similar to mine regarding seal failures .
In my experience most seal failures are seen with intercept.
My top 2 ( best ) are DuraLite and XL Edge followed by super spacer.

This post was edited by mmarse1 on Tue, Mar 5, 13 at 16:10

The window manufacturer is giving me a choice of either,for the same price.
He claims his company favours XL edge because of greater reliability(about .2% failure,vs up to 6% with ss)
The windows are warranted for life,so they want fewer problems.

My experience is the opposite, but both are very reliable. In my experience, SS runs a slight premium, so perhaps that is why he'd rather give you the xl.... Or, maybe he is telling the truth, lol. I'm sure results can vary as they say...

Super Spacers are usually a bit more premium in our area as well from a pricing standpoint.

Either will serve you well.

I was a little surprised to see a question comparing XL and SS apparently involving the same window company because, performance aside, logistically there is a great deal of difference between the two products.

The XL spacer is only used in Cardinal IG units that are manufactured at a Cardinal IG plant and then sold to the window company, whereas SS is almost always used in IG units fabricated directly by the window company.

I know of window companies that fabricate their own IG's primarily using Intercept as the base product but who offer XL as an upgrade; and I know of companies who fabricate their own IG units using Intercept as the basic spacer and offer SS as the upgrade; but I can only think of one company off the top of my head that offered both SS and XL option (among other spacer options) - and that company recently stopped making their own spacers for 100% XL.

Also, there are window companies that have multiple plants around the country, that started life as separate companies, who were then acquired by the parent to become part of that organization.

As separate companies these plants had materials and processes in place that were not changed after acquisition by the larger company. So in those cases the same company might offer various IG unit options based on what plant the window comes from. Those differences could be more a cost-saving legacy issue rather than a specific corporate decision to offer variety.

Performance-wise, SS is going to be about 2 1/2 degrees warmer than XL at edge-of-glass in the same application. Edge-of-glass is the outer 2 1/2" of the IG unit while center-of-glass is the rest of the IG unit or all the glass area that isn't within 2 1/2" of the edge (and just to clarify, the 2 1/2 degrees versus 2 1/2" is just coincidence, there is no direct correlation in case anyone was wondering).

Per durabilty or longevity, that is harder to quantify, once again because of basic logistical differences in the two products.

As mentioned, XL is produced at a Cardinal facility and sold to the window company as a complete IG package. Cardinal offers the window company a 20 year warranty on the IG unit (what's offered to the consumer is up to the window company).

If an XL IG unit fails, the window company makes a claim to Cardinal, based on the 20 year warranty, making it relatively easy for Cardinal to track IG field failures. As you mentioned, Cardinal has about a .2% 20 year failure rate with XL.

With Superspacer (or duralite, or duraseal, or intercept, or swiggle...), with few exceptions it's the window company who fabricates the IG unit using whichever spacer they choose.

This can be good or this can be bad. A window company that makes a high-end, high quality window is likey going to make a high quality IG unit as well. Quality is part of their process. They are likely to have a world-class Lysec IG fabrication line, high-end washers,QA inspection, and so on.

Whereas why would a company that makes a low-end window make a high quality IG, no matter what spacer they are using? Basically, anyone who wants to fabricate their own IG units in their garage can buy Superspacer materials on line.

The high-end company very likely has excellent durability and longevity; probably not so much the low end company.

Also, there are various materials "approved" by Edgetech (parent of Superspacer) to seal the IG unit using Superspacer - hot melt butyl, polysulfide, silicone, among other sealants are all on the list. Some of these materials are more reliable in that application and some are less so. It isn't surprising that the better performers are the more expensive products while the least expensive materials are also the poorest performers.

Edgetech does not offer an IG warranty since all they do is sell component parts. There really aren't any reliable field failure statistics available for any spacer system other than XL.

So what all that verbage means is that it is entirely possible that company X has a 6% field failure rate with Superspacer, whereas company Y has a half percent field failure rate. It really depends on the manufacturer of the IGU.

This is one reason (in my opinion) why Intercept has a poor reputation, for example.

One thing cardinal does is edge delete. I firmly believe this significantly adds to their low failure rate.

What window companies use Cardinal Glass XL besides, Marvin, Anderson and Sunrise?

I believe Joyce Windows offer XL Edge.

By the way, that was one hell of an explanation Oberon. Thats about as good as it gets.

On their website, Cardinal simply states that they have more than 500 window customers in North America. I suspect that number is conservative.

I also suspect that virtually all of the major wood window manufacturers use Cardinal IG's in their windows - if not in every line or product.

Among vinyl companies it is more hit-or-miss and you would have to check with them to see what they offer.

Also, Cardinal recently introduced a new spacer known as Endur.

Endur is a stainless steel spacer that Cardinal states will have the same longevity ("endurance", per Cardinal), as the XL, but with a degree or two temperature improvement at the edge.

I do know that a number of window companies have switched over to Endur, but I don't know precisely who or how many have partially or fully changed to the new spacer.

Thanks krypton.