Many of us are converting our garages into workspaces and adding things like air conditioners and heaters to make it habitable for year-round use. To make your garage as energy-efficient as possible, make sure the door is as insulated as possible. Avoid garage doors with windows; they are rarely well-insulated and can leak air very easily. Try to use “triple-layer” doors, which have foam insulation that protects from the elements. And if you use a garage-door opener, opt for one that is designed for low-energy standby mode; it won’t draw as much energy when it's not in use.