Keeping the Cold Out of Old Windows
Notes on foam tape, V-strip weatherstripping, and sash alignment — practical approaches for reducing heat loss in Canadian heritage homes without altering their character.
Practical Guides on Window Sealing
Self-adhesive foam tape is often the first material people reach for when sealing a drafty window. This guide covers material selection, surface preparation, and common mistakes that reduce tape lifespan.
Tension-seal V-strip (also called pile weatherstripping) fits inside the sash channel and remains hidden when the window is closed. A durable option for windows that open and close regularly.
A sash that no longer closes flush is a common source of drafts in older Canadian homes. This article examines causes — seasonal wood movement, paint build-up, worn hardware — and remedies that preserve the original frame.
Why Heritage Window Sealing Is Distinct
Older wooden window frames expand and contract with humidity and temperature cycles. A seal applied in summer may compress so tightly by winter that it tears; one applied in winter may leave gaps when the wood swells in spring. Material choice and installation timing both matter.
Many provincial and municipal heritage guidelines in Canada restrict alteration of original window fabric. Draft sealing using reversible, low-impact materials — foam tape, V-strip, rope caulk — generally does not trigger permit requirements and leaves the original sash intact for future restoration.
Heating season in most Canadian cities spans six months or more. During a cold January in Ottawa or Winnipeg, a single poorly sealed double-hung window can account for a measurable portion of room heat loss. The specific gain depends on window size, outside temperature differential, and existing glazing type.
Foam tape suits fixed or infrequently operated sashes. V-strip suits active sashes where the window opens seasonally. Rope caulk is removable and used for seasonal sealing of fixed panes. Each material has a different cost, lifespan, and installation requirement.
Authoritative Sources on Window Energy Efficiency
NRCan publishes guides on home energy efficiency, including window insulation and air sealing. The Keeping the Heat In publication covers draft sealing in detail.
nrcan.gc.ca →Provides climate data useful for understanding regional heating degree days, which inform the economic case for window sealing in different parts of Canada.
canada.ca →Guidance on maintaining heritage buildings in British Columbia, including notes on window conservation approaches compatible with energy sealing.
heritagebc.ca →