rehabing a 10 year old sun room to make a little more air tight. In the process of air sealing now and will be removing vinyl siding to add EPS. I also plan to add an overhang to shade the South facing windows.
The windows are Harvey vinyl rolling with dual pane glass (no lo-e or argon). The solar heat gain is cooking me in the summer which I hope will be cured by the overhang.
I am considering replacing the existing windows with the same model rolling which has tripple pane/lo-e/argon (u-.20) but, I dont like the VT of .37
The other option is the cheaper Anderson 200 rolling (u-3.0) because I feel it has a better weather strip system.
Does anyone have feedback on air infiltration for rolling windows in general? Can the NRFC labels be trusted?
There is no doubt that my Anderson casements seal better  than Harvey double hungs but is that because they are casements or is it the wood frame vs viny frame?
Any thought appreciated.

AT CT to ME 2007,

Posted By freakboy on 09 Aug 2010 11:50 PM
Does anyone have feedback on air infiltration for rolling windows in general? Can the NRFC labels be trusted?


AT CT to ME 2007,

sliding windows are generally the worst for air infiltration, casements the best and are also available in vinyl with low "e" /argon filled insulated glass and well suited for your application

If you are correcting the SHGC with the addition of the overhang, you would be better suited to go with a higher SHGC window than offered in a triple pane to grab some of that winter passive solar heat.

As mentioned, stay away from Sliders.

update on plan. turns out the sliding sashes I have are screwed together. I have ordered new low-e/Argon glass only for the sashes and plan to reassemle them filling the hollow vinyl chambers with spray foam. Wish me luck. Glass was only $400.00

Posted By freakboy on 30 Aug 2010 08:55 PM 
  filling the hollow vinyl chambers with spray foam.

could be a mistake , if not intended for foam fill they could swell up and not be useable, I would leave the hollow space "as is" as it is also insulation

If you had access to an insulation blower you could probably safely blow the hollow bits full of high-density blown fiberglass or EPS beads, but it's a miniscule amount of material, not worth buying a bag & renting the blower. Expanding foam is too risky.

Exterior roll down shades can be more effective than overhangs, but they'll mess with the view. They give you a lot of control over the solar gain though- much more than with fixed overhangs.

So how do the factories do foam filled frames then? They have to inject the foam into the extrusions somehow.

Update,
I only ordered 1 sash to try this out. First challenge was determining which side had the low-e coating on it. used the flashlight/lighter test to determine the proper side. as it turns out 1 side of the sash frame has aluminum tubing inside so there is somthing to screw the sash locks to. I was able to fill 3 sides and the all important corners of the knock down frame. I used great stuff window/door (blue can) and have plenty of experience with it. I drilled holes about every foot around the perimeter and fed the straw in each way, easy once I figured out best place to drill holes to reach the corners. To keep the foam from getting all over the sash I covered the edge/sides with blue tape ( even though I find it does not stick very well to this manufactures product and some oops are easily scraped off when dry).
I decided to clean the window frame real well prior to installation. There are removable aluminum tracks on the bottom which the rollers slide on and once removed I found a huge souce of air infiltration. As someone posted previously there are drain holes which lead directly to outside for the water to drain away. No big suprise now why these windows are so drafty.
To answer Greentree question on how the factorys do it I only have info on Harveys vinyl. I recently installed 4 double hung units for a customer and did some investigating on them to find they put loose 1/16" sheet stuffed inside. Apparently they only stuff in enough to get to the federal tax code.

Posted By greentree on 02 Sep 2010 08:34 AM
So how do the factories do foam filled frames then? They have to inject the foam into the extrusions somehow.

Drop tubes with a low-expansion/low-pressure polyurethane foam.

Difficult to fill properly.  Many manufacturers now use a rigid inserted foam.

Foam, in a majority of the cases, does little to nothing to the U-Factor on the window.

freakboy;

as soon as you alter a window frame or sash by drilling holes , you have most certainly voided the warranty the small alleged benefit is not worth the damage caused

freakboy,
So now that you plugged the weep holes are you just going to let the sashes sit in a puddle?

Sliders being leaky has more to do with the sashes just sitting on a track with no pressure applied to seal the sash to the weatherstripping. Casements are much tighter due to the fact that you are pressing the sash into the weatherstripping with the cam action of the lock. The way you remove a slider sash compared to a double hung is the reason double hungs are slightly better and not just a slider on its side.

Posted By greentree on 04 Sep 2010 10:39 AM
freakboy,
So now that you plugged the weep holes are you just going to let the sashes sit in a puddle?

Sliders being leaky has more to do with the sashes just sitting on a track with no pressure applied to seal the sash to the weatherstripping. Casements are much tighter due to the fact that you are pressing the sash into the weatherstripping with the cam action of the lock. The way you remove a slider sash compared to a double hung is the reason double hungs are slightly better and not just a slider on its side.

This is absolutely the truth.  If you fill that extrusion with foam, you are going to potentially creating issues for yourself.