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Draftproofing

What should I know about draftproofing?

Three essential elements of an energy-efficient home are airtightness (achieved through draftproofing), insulation (ample amounts) and sufficient ventilation. Combine all three, you get a comfortable, low-energy, lower carbon home with excellent indoor air quality year-round and lower heating and cooling bills. Additional benefits include reduced drafts, noise, and moisture problems.

Reducing air leakage through draftproofing (also known as air sealing) is a cost-effective, energy-saving measure that you can undertake without hiring a contractor. The leakier the home, the greater the opportunity for improvement and energy savings. In addition to reducing heat loss and energy bills in the winter, draftproofing keeps your home cooler in the summer, and improves the comfort and health of your home.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

Where do I start to reduce drafts and improve my home?

The first step to reduce drafts is to identify the air leakage areas throughout your home. Although you might feel drafts and see air leakage areas around windows and doors on the main floor, in most homes, the most significant air leaks are often found in the attic/top floor and basement/lowest floor and are often hidden. This is due to the stack effect: In a heated home, less dense warm air rises and expands, creating a higher-pressure area near the top of the house. As cold air pushes into the lower portions of your home it forces the lighter warm air up and out through leaks at the top.

In general, the priorities for air sealing are:

  1. Large holes regardless of location (plumbing or electrical penetrations, ductwork through unconditioned spaces, large gaps under doors, masonry chimney chaseways)
  2. Smaller holes on top floor ceiling/attic (pot lights, ceiling penetrations around fixtures, attic hatch, attic knee walls, service shafts, etc.)
  3. Smaller holes on the bottom floor (hose bib penetrations, cracks on exterior and foundation walls, basement doors, electrical boxes, gas lines or oil fill pipes that go through exterior walls, etc)
  4. Smaller holes on main floors (windows, doors, top and bottom of baseboards, fireplace dampers, electrical outlets, switches)

For a more in depth air sealing analysis of your home, you can have an EnerGuide Home Evaluation performed on your home to find any obvious or hidden drafts that need sealing. A program-qualified energy advisor will come to your home, perform a blower door fan test/depressurization test and look for air leaks. The advisor will also use the data from the depressurization test and calculate the air leakage rate for your home. In the Renovation Upgrade Report provided by the energy advisor, will include a prioritized list of draftproofing measures for your home.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

Can I draftproof my home too much and make it too tight?

Reducing the air leakage in your home through draftproofing (air sealing) and other home energy improvements such as installing windows can increase your comfort and reduce your energy bills. However, when air sealing your home, it is very important to ensure that your home is still getting an adequate supply of fresh air. As part of your home energy improvement plan, ensure there will be sufficient mechanical ventilation to supply fresh air, and maintain good indoor air quality in your home. Many older homes are drafty and naturally ventilated through air leaks in your home; however natural ventilation may be allowing moisture to enter your building envelope or be pulling unwanted air from your attic into your living space.

To ensure your home has adequate ventilation, have an EnerGuide Home Evaluation performed on your home. If your home is too air tight, an energy advisor may recommend adding a balanced ventilation system, such as a heat recovery ventilator (HRV) to ensure adequate ventilation.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

What are the benefits of draftproofing?

  • Consistent comfort: Reduces drafts and maintains more even temperatures throughout your home.
  • Quiet comfort: Reduces unwanted outdoor noise.
  • Save money: Reduced energy consumption results in lower utility bills.
  • Climate friendly: Reduced heat loss means less energy needed to heat your home resulting in a smaller carbon footprint.
  • Reduced maintenance costs and improved durability: Your home lasts longer due to reduced condensation. This helps to prevent rot, mold, and mildew.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

What is combustion spillage and how can it be tested?

Combustion spillage is a term used to describe the unwanted flow of combustion gases into your home. The quantities involved are usually small; however, combustion spillage is a serious health hazard and should be dealt with as soon as possible.

If your home has any of these combustion appliances you may have risk of combustion spillage:

  • Gas-fired furnace, boiler, or water heater
  • Oil-fired furnace, boiler or water heater
  • Wood stove or fireplace
  • Portable propane, natural gas or kerosene heaters
  • Other fuel-burning devices (e.g. gas range)

Normally, these combustion products – which can include both visible smoke and various invisible gases – are vented to the outdoors through a chimney or vent pipe. Unfortunately, in some circumstances they may instead escape into your home, which can cause a variety of health concerns.

How is combustion spillage tested?

If you have any of the combustion appliances mentioned above, an exhaust devices depressurization test (also known as a combustion spillage test) can be performed to test your risk for combustion spillage. The test can be performed by an energy advisor,and involves running all of the exhaust fans to test  whether combustion gases can be pulled into your home by the exhaust systems. This test is a routine part of every EnerGuide home evaluation for homes with combustion appliances. If you are at risk, the energy advisor will let you know, and provide guidance on who you can contact to address the problem.

Please note, if a building inspector requests a combustion spillage test after you’ve completed a kitchen upgrade, you will need to have a combustion spillage test performed by a professional with heating, ventilation, and air conditioning (HVAC) or Thermal Environmental Comfort Association (TECA) certification. Not all energy advisors are qualified to perform this specific combustion spillage test, unless they have HVAC and TECA certifications.

For more information about combustion spillage, its causes and how to prevent it, visit Natural Resources Canada.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

How do I draftproof my home?

A tight air barrier from careful draftproofing (air sealing) and ample insulation are critical parts of your home’s building envelope. The air barrier can be on the inside or outside of the wall and reduces air leakage. Draftproofing is simply sealing any openings in the air barrier that allow for the transfer of warm and cold air between the inside and outside of your home. Draftproofing methods and tools include the appropriate application of caulking, weatherstripping, and films to seal air barrier holes or gaps. Draftproof first, add ample insulation, and then ensure adequate ventilation.

The following diagram shows common air leakage areas:

DRAFTPROOFING DIAGRAM LEGEND

  1. Sill and header
  2. Windows
  3. Electrical outlets
  4. Foundation cracks
  5. Floor drain
  6. Service lines (gas pipes, etc.)
  7. Mail slot
  8. Doors
  9. Ceiling penetrations (chimney, light fixtures, plumbing stack vent, etc.)
  10. Exhaust fan vents (range, bathrooms, etc.)
  11. Attic hatch
  12. Chimney
  13. Fireplace including area around perimeter

After identifying the air leaks, there are many do-it-yourself ways to reduce drafts in your home:

  • Seal around doors and windows with weatherstripping
  • Apply insulator film to your windows
  • Put in foam pad sealers on outlets and light switches on exterior walls to prevent cold air from seeping through
  • Seal small holes and cracks by caulking around ducts, pipes, exhaust fans, vents, sink and bathtub drains, fireplace and under counter-tops

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

What are the costs of draftproofing?

Reducing air leakage can be the most cost-effective, energy-saving measure a homeowner can undertake; the leakier the home, the greater the savings. Typically it is more cost-effective to have a well-insulated, airtight house with mechanical ventilation than a poorly insulated house that relies on leaks and holes in the walls for fresh air. The cost of careful draftproofing and ample insulation is offset by reduced heating and cooling costs over the life of the home.



Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

Can I hire someone to draftproof my home?

Draftproofing can be a do-it-yourself project or you can hire an experienced contractor to do air sealing work for you. When hiring someone to draftproof your home, obtain multiple written quotes and be sure to ask how much experience they have draftproofing. Ideally, the contractor should use a blower door while draftproofing to ensure a quality job and to confirm that their work results in an air leakage reduction. Many insulation contractors offer draftproofing services as part of their insulation installation services.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

Where are the biggest air leaks in my home?

The biggest air leaks will often come from attics, basements and around chimneys. Identifying and addressing the air leaks in these areas will have a greater impact on improving your home’s comfort and reducing your utility bills. However, there are many air leaks that you can quickly identify and seal yourself such as leaks around electrical outlets, windows and doors. For more information, visit ENERGY STAR®.



Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

Where are the biggest air leaks in my basement?

The most common locations for basement air leaks include:

  • Along the top of basement walls where the cement or block foundation comes into contact with the wood frame
  • Holes for wiring and plumbing going into external walls
  • Any holes or gaps where the electrical, gas or oil fill pipes go through the wall
  • Furnace flues
  • Leaky ducting or poorly fitted hot-air registers
  • Around window and door framing
  • Cracks in the foundation wall and slab
  • Floor drains

For more information, visit ENERGY STAR®.

Did you see a building science or energy efficiency term you did not understand? Check out our glossary.

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