To retrofit means to fit something up with new or modified parts, elements or equipment that usually were not available when the thing was manufactured. It is a form of modifying, or adapting to a new purpose or need. The something that is retrofitted can be almost anything, e.g., mechanical equipment, airplane, or a building. For environmental purposes, retrofitting buildings, either commercial or residential, is designed to make them more energy efficient by reducing greenhouse gases (GHGs) emitting from the building.
Some of the means of retrofitting buildings for climate change include replacing oil furnaces with new boilers using natural gas, or, better yet, with electric heat pumps that rely on the heat in outside air, if the electric grid is decarbonised with renewable energies. Other means include replacing older lights with LED lights, with sensors that turn on the lights only when someone is present in the space to be lit; tight, insulated windows or walls; green roofs; or, smart utility meters
Older commercial buildings can often be retrofitted easier than residential buildings because the owners often have more resources and can pass along the costs to tenants. Owners of residential buildings can recoup expenses for retrofitting from the savings in energy costs from more efficient heating or air conditioning systems, but the upfront costs are sometimes prohibitive.
Some further ideas to explore on Retrofitting:
Explore all the means of retrofitting your residential space.
Choose one, and determine what it would cost and how you could fund the retrofit.
Determine what you would save in lower energy bills if you did the retrofit, and if your carbon footprint would be lower.
Jefferson Kolle, “An Easy HVAC Retrofit for Old Houses,” Old House (18 April 2019). bit.ly/3aVpc38
Nic Fleming, “Retrofitting older buildings: innovations and necessity,” The Guardian (20 May 2014). bit.ly/2KJEIo6
Landlease, Retrofitting old buildings can provide immediate environmental benefits bit.ly/2WcL5FP
U.S. Office of Energy Efficiency & Renewable Energy, Retrofit Existing Buildings bit.ly/2WaSo0I