While new construction can be flashy and exciting, retrofitting or renovating an existing building is an excellent opportunity to reevaluate its energy usage.
Retrofitting allows existing buildings to take meaningful steps like recommissioning and upgrading energy systems, improving the building envelope to more air-tight, and install efficient lighting to improve their energy performance and to save on utility and maintenance costs down the road. Many utility companies even offer incentives to reduce the costs of retrofits. The City of Chicago also has a program emphasizing energy efficiency in existing buildings; check out more information about Retrofit Chicago here.
As anyone with drafty windows will tell you, windows and doors are one of the primary locations for air infiltration and drafts. Air leaks can sometimes be fixed by using caulk or by weatherstripping. Retrofitting to double or triple pane windows is more expensive, but can also make a huge difference, even more so if the air gap between panes is filled with an inert gas (like helium, neon, and argon) since heat travels through those gases less easily than typical air. Tinting, shading, and/or the addition of a thermal break are also options that can reduce heat gains and losses.
A great first step when considering a retrofit project is to have an energy home audit completed by a professional. Watch this video about energy assessments to see where to start!