While I can not share experience on the Certainteed product I am experiencing identical problems on Comfort Line Fiberglass windows. Unfortunately all are leaking and it is not an installation problem as I removed siding to add house wrap and this gave the installers direct access. I also participated in the foam sealing and urethane window wrap.

I'm extremely curious to see what the pros out there think about this since the Bryn Mawrs are one of two windows I'm considering using along with the Ellison 1500 series.

Hopefully it's just something simple that the installers overlooked, and that they will fix it without a hassle. I've read of many instances like this where the manufacturer and the installer blame each other while the homeowner is stuck in the middle with bad windows/bad install. I hope you get it sorted painlessly, and I'll be keeping an interested eye on this thread. Good luck!

It's hard to tell fom the pictures. If the window wasn't squared in the opening, it's possible it could be an installation problem. Try putting a small level on the top of the lower sash at the meeting rail and then use a T-square in each corner. It's also possible the installer bowed the frame. Also, look at the outside and see if the weep hole covers are closed securely

It may also be that the frame and sashes weren't matched well during the manuf. process. Do you see a difference in the gap between the tops and bottoms of the sash? You can also unlock the sash and see if there's a lot of horizonal movement between sash and frame.

I'd also check and make sure you haven't developed another escape route for air such as a bathroom fan.

Sorry I can't be of more help without seeing the window from the inside and outside. Call your contractor and see if he will help and if not, call Certainteed.

Good luck.

I've been seeing a lot of complaints this year on air infiltration issues. As Skydawggy explained above, it's very difficult to isolate the issue without really being there to look the window over. Most of the issues I've seen lately are related to the weep holes some how venting back into the home. I'm not sure what type of weeping system the Bryn Mawr window has. Hopefully they have some type of damper or flap that blocks air from blowing back into the window. The flap will open to let water out, but cover the hole when air tries to come back in.

The issues I've seen lately have been related to these flaps getting ice build up and freezing open. The air will then infiltrate the hole and enter the home. Some of the vinyl and fiberglass extrusions have connecting chambers that are open all around the window for entering air to find ways out. I've noticed open chambers up the sides that can vent out through the fastener holes. That's why most manufacturers send some type of hole plug to seal the fastener holes after installation. There are a lot of installers that don't seal these holes up after installation. Make sure the holes are plugged where the installer has fastened the window. Even if they have used low expansion foam and capped the exterior properly, air can still gain access through the weep holes if they don't shut properly.

The other big leaking spot is the reveal between the window sash edge ad the frame like Skydawggy talked about above. The sash has to seal up against the frame in order to seal the unit. Yours look tight from the picture but it's tough to tell. There should also be a foam seal at the bottom of the spring track that your husband has foamed. If you open the lower sash up there should be some kind of seal in that track that stops any blow back air from getting up under the closed sash. If there's nothing there to block the air it can blow under the sash and up the track. It kind of works like a fireplace chimney and vents up the open track. See if any of these issues are relevant to what you have and post back. Guy

Ply Gem Windows who bought Certainteed in California has remade the double hung and is now part of their Premium line which is pretty good. Most of Certainteeds lines are being replaced by Ply Gem lines because of issues like this.