Draft-Proofing Doors and Windows to Lower Heating Bills
Cold air rarely enters through one dramatic gap. It usually leaks through small cracks around sashes, door bottoms, letter plates, keyholes, loft hatches, and service penetrations. A 3 mm gap along the bottom of a 900 mm door can behave like a permanently open hole. The U.S. Department of Energy says air sealing and insulation …








































