The Biggest Bang For Your Buck: Air Sealing  

You’ll Need: ~$400-$1000 for air sealing supplies (like weatherstripping and gaskets) and a blower door test (the cost of that is included in an energy assessment). These fixes usually take a week or two, but they really pay off. 

All of the little holes in your home (like where vents are cut to the outside and where pipes/wires enter your home) REALLY add up. Here are two quick examples to show you what we mean: 

1. One of our volunteers lives in a 1910 semi-detached home in central Toronto. Their blower door test revealed a total air leakage area (all of the little holes added up together) of 495 square inches —that’s like having a nearly two-foot by two-foot hole in the wall all year round! In their case, air leakage accounted for half of the home’s annual heat loss. They would have never known this without doing a blower door test. 

2. This air sealing case study from the Pocket Change Project shows the importance of a blower door test. Their tests revealed they had an incorrectly installed range hood in the kitchen that was leaking an incredible amount of air— their air leakage measurements were literally off the charts.  

   
   

Sealing these holes is usually the biggest bang for your buck when it comes to updating your insulation. Hiring a professional to run the test is worth its weight in home comfort.  

Check out a blower door test in action in this video from PBS.

Big Insulation Fixes In Your Attic, Basement, and Walls 

You’ll need: $2000-~$35,000. These are big jobs! This includes the cost of an Energy Assessment, as well as material and labor for major insulation upgrades. 

If air sealing isn’t cutting it, then a bigger fix might be in order. The scope of this project is bigger, so we won’t try and cover everything here. Here are some quick tips based on case studies and advice from our experts.  

Walls 

The Pocket Change Project has a few examples of people updating their wall insulation: 

Less Disruptive: These homeowners hired a contractor to blow insulation into existing cavities in their walls.  Small holes are drilled, the insulation is added, then the holes are patched up again! It cost them ~$12,000 all in, and it dramatically improved the comfort of their home. Not all homes work for this, though — you need space in the walls. 

 Exterior Insulation: If your home doesn’t have space in the walls, insulation will need to be added to the outside. The process is like adding a new wall: a frame is put up, then insulating is added, then it’s covered with siding. Two case studies cover this: Jeb paid $25,000 for his work, while Gina paid $34,500 — both have much improved home comfort.   

Basement 

Foam padding can be added around unfinished basements to improve the insulation. 

Attic 

Your fix will depend on whether your attic is occupied or unfinished, but Toronto homes are unlikely to have lots of extra space up there! Borrowing from the Less Disruptive wall fix, insulation can be blown into cavities between the top floor and the roof to improve its insulation.  

A quick note on spray foam: Attic insulation and spray foam are usually tied together, but advice varies widely on this. CBC has articles about people abandoning their homes because of toxic off-gassing, but there are better certifications in Canada than the US. The middle ground seems to be: under perfect conditions, spray foam is safe and works, but perfect conditions are rare and the risks (not to mention the climate impact) are high. Cellulose alternatives are great.  

Are there rebates for this? 

You won’t get any money back for doing a DIY job, but Ontario’s Home Renovation Savings Program has generous rebates for air sealing and insulation (as long as your get an Energy Assessment done before and after the project). We have a deep dive on rebates here!