1. We should learn about PVC profile, hardware fittings and the assembly quality of plastic-steel doors and windows. PVC profile reasonably designed has multiple cavities and thicker walls, contains anti-aging agent and ultraviolet-proof auxiliaries, and looks bright, clean and bluish white. Medium and low-grade profile is yellowing in white, has poor sunscreen capability, and will become yellow gradually until aging, deformed or brittle because there is much calcium in its formula. The wall thickness of profile should be larger than 2.5mm, and the three-cavity structure (including closed draining cavity, isolation cavity and enhanced cavity) will prevent the window from deforming (you can claim different profile sections from manufacturers for comparison).
2. It has smooth and flat surface, without open weld and cracks. The sealing strips should be flat without crimping and off-from-slot, and the adhesive tape is odorless. When the door and window are closed, there is no gap between sash and frame, the sliding plastic-steel window is free to move, no sharp noise and dust dropping.
3. There are special steel lining embedded in profile of frame and sashes. The glass should be flat and free from watermark and mounted securely, the installed glass does not contact the profile directly, and the gaps are sealed by sealing strips rather than glass cement. There is no dust and vapor in the interlayer of double glass.
4. Hardware fittings are complete, installed correctly and securely, and are easy to use.
5. It would be best to choose plastic-steel window with hollow glass for residential buildings having large noise outside, which shows excellent sealing and sound insulation.
6. It is necessary to consider the functions, good-looking appearance and coordination with the surrounding in design of window pattern.
7. Shall make clear name and specification of plastic-steel window on the invoice and contract.