By not covering up your HVAC registers and vents, it’s like leaving windows and doors open. Our insulated magnetic covers create a barrier around ceiling and wall registers eliminating heat loss and cold drafts during the winter when your Central Air Conditioner is not in use. If you want to reduce energy costs and feel more comfortable then this product is for you! From the Manufacturer By not covering up your HVAC registers and vents, it’s like leaving windows and doors open. Our insulated magnetic covers create a barrier around ceiling and wall registers eliminating heat loss and cold drafts during the winter when your Central Air Conditioner is not in use. If you want to reduce energy costs and feel more comfortable then this product is for you!