Save energy. Sumum PVC windows technologycan can save up to 68% of your energy bill. Noise insulation. Silence is comfort. Sumum windows can reduce external noise up to 32 times (50dB). Security. Sumum PVC windows are reinforced and use premium brand locks to offer you a very safe window. Insulation. Sumum windows protect you from cold, heat, rain and wind. Youwill be comfortable no matter how the outside weather.