Building Envelope or Shell

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The building envelope is the shell made up of the windows, outside doors, walls, foundation, floor and roof. The more energy-efficient the building envelope, the less energy you will need for heating and cooling the interior.

Make your building envelope more energy-efficient

• Seal cracks to prevent energy loss
• Weatherstrip around windows and doors
• Install energy-efficient windows
• Consider windows with prismatic glazing
• Fix doors and windows to operate properly
• Use window coverings effectively
• Reduce solar gain
• Add roof insulation

Seal cracks to prevent energy loss
Use caulking or other expandable materials to seal:

• Around window and door frames
• Where walls meet the foundation
• In the foundation itself
• Around window air conditioners
• Around the chimney
• Around openings where piping, electrical and telephone lines enter the building

Block unused openings in the walls or roof to prevent additional energy loss.

Weatherstrip around windows and doors
A pair of exterior doors with no weatherstripping can create a gap equivalent to a 12-cm-diameter (five-inch) hole that air constantly leaks through.

• Replace worn-out weatherstripping.
• Close windows and exterior doors when operating air conditioning or heating.

Install energy-efficient windows
Energy-efficient windows, new or retrofit can reduce annual building energy costs by 15%. They are less drafty, lose less heat and as a result cause less condensation.

Consider windows with prismatic glazing
Window films, such as prismatic glazing reflect direct light and heat out of the building to control interior glare and limit cooling costs, while angling light towards the interior ceilings for maximum light distribution.

Fix doors and windows to operate properly
Ensure your:

• Exterior doors and windows close tightly
• Interior doors to unheated areas close tightly
• Automatic door closers operate quickly, completely and safely 

Use window coverings effectively
In the winter, close curtains, shades or blinds during unoccupied periods to retain heat. However, be sure to open them on sunny days to take advantage of winter sun. In hot weather, these window coverings can also prevent some heat gain.

Reduce solar gain
Install shades and awnings in the south and west facing windows to prevent overheating and too much glare from the sunlight during the summer.

Add roof insulation
Insulate your roof to reduce heat loss through the roof and take advantage of the low cost of adding insulation at the time you replace your roof.