- Energy saving solution. Maximize energy efficiency and reduce your carbon footprint with this air conditioner window seal. It blocks backflow of hot air, lowers power consumption, and is an environmentally friendly, cost effective solution that is easy to install and remove. - Durable and weather ready. Made of high quality waterproof polyester, this seal provides long lasting use and windproof protection in all weather conditions. - Easy installation, no tools required. Place the hose, open the zip, tighten the seal, attach it to the window frame and enjoy an airtight seal for cool comfort. - Simple, year round temperature control. Keep your room cool in summer and warm in winter without removing the window seal. Open or close the window as needed, and reinstall easily next summer. - Use scenarios - Home or apartment with a window air conditioner: prevents warm air from entering and reduces energy waste. - Rentals or windows you cannot modify: no drilling or permanent installation required. - Seasonal ventilation: keep the seal in place for most of the year and use window opening for controlled ventilation as needed.