Air Drafts and air infiltration in a house

Have you ever felt a cold air draft on your skin, when inside a building? This is caused by air infiltration, the air movement into a building, a home or a structure.

Air infiltration into your home can affect your building in the following ways

More energy costs

To control a building’s climate, we need to add or remove heat from the building’s interior. This consumes energy and money.

Air leakage into a building’s interior increases energy consumption even more because if the building’s envelope has openings, air will move freely in and out of the building. This will affect the energy required to cool or heat the building. According to experts, air infiltration accounts for 25–40% of the energy used for heating and cooling in a typical home.

Air drafts in Old and new buildings

Nowadays, contractors use sealing products such as foams, house wraps, sealants, and tapes to airtight the building’s envelope to eliminate air infiltration.

Unfortunately, this practice was not always common. In fact, buildings built before the 21st century suffered air infiltration problems. Many older homes are not well insulated or sealed, and as a result, air leakage is a common problem in older homes.

Less Comfort for your Family or Clients

Aside from the financial damage, air leakage also causes discomfort to the home or building tenants as they may feel cold drafts of air during winter or uncomfortable humidity and heat in the summer.

How does air get into a building if the windows and doors are closed?

Air can seep into a building through openings in your home’s envelope, such as gaps between your window frames and the wall, gaps between door frames and the wall or small openings in the roof joints.

Small gaps and cracks in the envelope of a building are due to:

Poor installation of the building envelope’s components

  • If siding, doors, windows and the roof are installed improperly (wrong size of window or door, for example), there may be gaps or holes that will remain open around the elements.
  • Poor installation is also attributed to the unprofessional sealing of the openings around the envelope components. Sealing doors and windows require skills and experience; if the caulking is poorly installed, air and water may seep into your home.

Deterioration of building envelope components

  • Often the reason for air infiltration is the old age of your doors, windows or roof. Air and water infiltration may indicate that it’s time to replace them.
  • Deterioration of your home’s sealants: depending on the caulking product’s quality, caulking joints can last for 5–10 years (5 years or less if the sealant is of poor quality, 10 years or more for top quality). Cracked or missing caulking can allow water and air to infiltrate your home. Caulking and replacing old caulk are simple and effective airtight techniques that offer great returns on investment, preventing air and water infiltration.

How to detect air infiltration?

If you notice that your energy consumption is higher than normal or if you feel infiltration of air into your building, you should inspect your home’s envelope, doors, windows and roof.

How to find the source of air infiltration?

To stop or reduce air leakage, you first need to know where the air is entering from. Therefore the first step would be to trace the openings in your walls. The easiest and most cost-effective way to find gaps and cracks in your walls is using a burning candle to find where the air is entering from.

  • Close all your doors and windows and turn off any fans or HVAC systems.
  • While holding the burning candle, get closer to your door, your windows, electric outlets, and pay close attention to the movements of the flame.
  • If you notice that your candle’s flame is moving faster near your living room window, for example, check the exterior window sealants to see if they are intact or deteriorated.

To learn how to check your caulking, follow this link: How to inspect your caulking.

Apex Caulking on the south shore of Montreal,  can limit or prevent air drafts into your building

Reducing air leaks in and out of your home decreases heating and cooling costs, improves durability, increases comfort, and creates a healthier indoor environment. It is always recommended to contact a professional to help you inspect your home’s envelope and determine the cause of air leaks.


Calfeutrage Apex, South shore of Montréal can help you detect air infiltration and conduct an extensive inspection.