February 12, 2007

Which Low-E is Right for My Shop?

By Paul Bieber


You don’t have to work with one only. Soft coat low-e is perfect for some situations, and hard coat for others.

Here are some pros and cons:

Soft coat should be used when you have the lead time to get the product from a reliable vendor. Soft coat is better performaning, meaning it is more energy efficient than hard coat.

That is soft-coat’s only advantage–but it is the most important reason to use energy efficient glass so it trumps all other points.

The reasons to use hard coat, though, are many. And a lot of these reasons will add up to the point that some jobs are better in hard coat. Hard coat is in stock at most temperers and insulators, while soft coat is not as readily stocked. If you have a job that will require quick and unexpected replacements, like an elementary school, than hard coat may have an advantage. Every architect will specify soft coat, its your job to remind them of the replacement product dilemma. You probably have vendors that specialize in both hard coat and soft coat, so you can get what is needed, but availability is the key to quick replacement.

Soft coat is being improved every year. The manufacturers keep coming up with new and more energy efficient flavors, but reorders and color matching becomes more complicated. The hard coats have basically changed twice in about ten years, so you have a stronger chance of succeeding in color match on a job down the road.

Soft coat is more complicated to fabricate than hard coat. Buy your soft coat from a supplier that really knows how to handle it. There are lots of good ones. Most fabricating insulators can handle hard coat very well. The only mistake that’s really made with hard coat is to fabricate with the wrong surface out. Be sure to check that before installation. Ask your fabricator to put stickers on the low-e side.

Depending on your climate, some windows have low-e on the second surface and some on the third. Now you just hired a few new installers, who maybe came from another part of the country. Make sure your current crew knows what the glazing requirements are for the jobs they are working on.

If you fabricate your own replacement IG, then you can work with hard coat, just like any other product. Keep the glass clean, use good sealants and you’re fine!