Cardinal 366 vs Sungate 500

[JonDeb96]

We are looking to replace the window Glass in our house in the Mountains of Colorado. We live at approximately 8400 feet and all the Glass to be replaced is south facing. We have gone out for bids and the 2 promising bidders have different glass types in the quotes. One has Cardinal 366 and the other is Sungate 500 (both LowE).

The windows will not have any coverings and the heat retention during winter is highly desirable. The reverse in Summer is also wanted. There are a total of 51 pieces of replacement glass to be installed.

I am not experienced in windows and would like the recommendation of the experts. We are looking for a long lasting high quality replacment glass.

Which of the 2 window types will meet our needs?

Thanks

[Skydawggy.]

The 366 glass is very low solar gain and inappropriate for your application. The Sungate 500 has a U-factor of .33 and a SHGC of .72 iirc. You might also take a look at Cardinal 181. That would be my choice if the manufacturer offers it.

[Windows on Washington]

Guardian also makes a coating called their ClimaGuard 75/68.

75 on the VT rating and a SHGC of 0.68. Another good glass package for those passive solar homes.

[JonDeb96]

Thanks for the reply's. We are definately looking for the solar gain with Colorado Winters.

Neither offer the i81 or the Climaguard options.

So far it looks like the Sungate 500 is a better choice.

FYI the original windows were Oldach windows.

[Skydawggy.]

What brand of window are you looking at?

[Oberon]

As another option if the window company offers Cardinal's 366 then they should also have access to glass with Cardinal's LoE-180 (not to be confused with i81 which is a different coating). LoE-180 is a high solar gain coating with VT-80%, SHGC .69, and U-value .24 when used as a surface 3 coating.

[lf1]

Sungate 500 is a pyrolitic or hard coat low e. Cardinal's LE366 is a softcoat low e. The main difference between these products is in the summer. Sungate 500 allows direct sunlight to pass through the glass, great in the winter, not so great in the summer. LE366 has one of the lowest Solar Heat Gain Coefficients, which will significantly lower your cooling costs in the summer. You can use the window selection tool at http://www.efficientwindows.org to compare glazing performance and energy costs. If heating cost is your only concern, Sungate 500 is fine. If year round performance is desired, LE366 would be the better choice.

Another important item, since you are installing your windows at 8,500 feet, you need to either buy from a local company (the insulated glass must be made at an altitude similar to yours) or use breather or capillary tubes in the glazing to equalize the pressure. If you are using tubes, argon will not remain in the insulated unit. The performance without argon is .03 to .05 higher (lower is better). You may want to consider a 4th surface coating such as Cardinal's I81 to offset the loss in performance from the inability to use argon.

[JonDeb96]

To All Thank you for the responses. Learned a lot as we didn't realize how complex glass is.

We will be going with the Sungate 500 since our only real concern is the heating in winter. Summer his not an issue as natural shade will help there and no direct sunlight at mid summer.

We will be using a local company who is the one offering the Sungate 500.

Thank you again.

Jon