Quality Outstanding performance energy efficiency and easy maintenance make Therm-O-Loc Windows your best choice. Whether you're remodeling or building new, our quality materials, years of experience in producing windows proves Therm-O-Loc to be the ideal window to meet today's need for efficiency and affordability. Crane Vinyl SidingProtection With Therm-O-Loc windows you can rest easy, secure in the protection of our full warranty. All vinyl parts are guaranteed for a lifetime and the insulated glass units are warranted against all defects including fog-up for a period of twenty years. Value Because each window is specially built for you to exactly fit your opening, you can custom design the window you need. Select only the options you want from our large selection. From basement to attic, from basic to dramatic, the window you want is the window we'll build for you.