The stack effect
Warm air rises and escapes through the top of the house; cold air is pulled in at the bottom. The drafts you feel at windows are often air being pulled in to replace what leaks out the attic.
Where the big holes are
Attic floors around chimneys, plumbing stacks and light fixtures; the rim joist; and open crawlspaces. Together they usually leak far more than all the windows combined.
How we find them
A blower-door test depressurises the house, and an infrared camera shows exactly where the cold air comes in.
We can help: Air sealing — Stop drafts at the source — attic floors, rim joists, chimneys and plumbing chases.