With Old Man Winter knocking at our door, experts at Therma-Tru remind homeowners to check their doors to make certain they are not leaking air, which can increase heating costs. "Start by inspecting the weather strip around all sides of every door in your home to make sure it has not worn out," says Derek Fielding, director of product management for Therma-Tru Corp. "Stand inside near your doors on a bright day and look for daylight coming in through the door's perimeter. If you see light, that means external air is coming into your home, reducing the energy efficiency of the door. "This can be a simple fix if your foam-filled weatherstrip has permanently compressed, flattened out or cracked. However, if you're seeing large gaps, or if the door itself feels cold on the inside reflecting the temperature outdoors, then it may be time to upgrade to a more energy efficient entry door." Fielding recommends seeking out fibreglass entry doors that are thermally broken, meaning they insulate against both cold and heat. Steel doors can be thermally conductive and result in the transfer of temperatures quickly from the interior to the exterior, and vice versa. "Ideally, you're looking for a fibreglass door system with components that are engineered to work together to help maximize the seal between the door and the frame," says Fielding. "We follow this principle when creating our Therma-Tru® fibreglass doors so that the systems help keep heat inside the house to boost the energy efficiency of the home." Another factor that can help keep exterior weather on the outside of the home is the material used for the core of the door. The dense polyurethane foam used in Therma-Tru's fibreglass doors helps the doors achieve high thermal performance values. "Our solid fibreglass doors offer up to four times the insulation of many solid wood doors due to their thick polyurethane foam core," says Fielding. "This essentially creates an energy-efficient entrance to the home, helping you stay warm on those cold winter nights."