I wonder if anybody else has had the same problem with Loewen windows that I have had. The problem is that the bigger windows won't close properly. They just seem too delicate for a window that size.
What sort of Loewen windows do you have? My mother has the double hung ones and yes, she did have difficulty with them. She ended up having a private contractor not associated with the company come in and correct the fit. You might want to contact the company directly with your question and see what they recommend.
The Lowen windows I have had problems with are the large casement type, about 5x3 feet in size. The frame just seems too small for a window that size, and as a result the window warps when it is closed and doesn't come flush with the weatherstripping. To compound the problem Loewen has put the mechanism at the bottom of the Window creating an asymetric force on a windo that bends. It seems like a fundemental design flaw to me.
I didn't use double hungs, but a contractor told me he had problems with Loewen sliders. My feeling is that the source of the problem is window frame sizes which are just too small for larger sizes. Unfortunately Loewen has been unhelpful and I have had to get legal help to try to get the to respond. Very frustrating, those windows were expensive!