Making Existing Homes Net-Zero

About one-third of greenhouse gases come from the buildings we use today, and by 2050, 70 per cent of these buildings will still be standing. We can’t address climate change just by constructing new net-zero homes; we need solutions to make the 15 million homes Canadians live in right now net-zero to preserve a livable climate. Deep Retrofits are the solution.

A deep retrofit prepares an existing building for a net-zero, emissions-neutral future. With the right blend of mechanical and envelope improvements, a deep retrofit can reduce a building’s energy needs so much that it can get all of its power from emissions-neutral, renewable sources. Besides having drastically reduced operational emissions, or none at all, a retrofitted home looks brand new, is resilient in extreme weather events, has fewer drafts and uncomfortable temperature swings, and will have healthier and fresher indoor air. 

Effective retrofits also minimize the upfront emissions associated with construction (also known as embodied carbon) by paying close attention to the carbon footprint of the materials, waste, and processes used in a retrofit. 

The deep retrofit movement is still in its early days. There are relatively few experienced consultants and even fewer contractors who have completed net-zero-ready retrofits to existing buildings. To date, Canada has seen only a few successful examples of residential deep retrofits, generally the result of the fortuitous alignment of critical factors: enlightened owners, consultants trained in net-zero or passive house standards, and committed builders willing to prioritize net-zero or passive house principles despite profitability risks.

The road to net-zero can be a complex technical and financial challenge. This retrofit roadmap will help guide building owners, contractors, and residents in the pursuit of their net-zero destination.