We had issues with one large single hung window on 2nd floor of house installed 7 yrs ago. The window would not stay up and the screen kept falling onto our shared driveway. Guarantee says lifetime on windows. Contacted FM Industries. Had to pay $150 + tax for them to come and repair window. Service person came and after 2 visits repaired window but extremely stiff to open - told us to get jiffy lube for window which we did - still really stiff. Said he ordered new screen. Never came. Never contacted us again. We waited months, contacted company again. Another service person contacted us. We explained situation. He said he couldn't do anything - just order the same sized screen as the order - I explained screen fell out all the time so size has to be wrong and that the window was really hard to open - finally agreed to come and look at window - never came as promised - we still have an extremely stiff window and no workable screen and we are tired of calling to get this fixed. The other windows ($11,000) we had installed have had no issues. We were happy with the windows but the guarantee is useless if they will not follow up and fix problems - we paid for a service that was never completed. issue.