A few areas deserve special attention but do not limit your detective work to just these places. Inside the main living areas, check the following:

• window glazings for tightness and around the window sash and casing
• around the door, including the threshold and around the door frame
• electrical outlets and switches, including ones on interior walls
• exhaust fans and vents (these should vent to the outside and close properly when not in use)
• corners where two walls meet with an imperfect seal
• light fixtures in the ceiling
• interior trim and baseboards
• cracks in the wall finish or ceiling
• the joint where a wood frame wall joins a masonry wall or chimney
• doors and hatches into unheated attics
• fireplace dampers and fireplace bricks
• behind bathtubs and under sinks
• above sliding pocket doors
• around plumbing pipes and ductwork

Inside the attic, check the following (you may have to move aside existing insulation):

• around the plumbing stack and any other pipes entering the attic
• around wires or ceiling light fixtures that penetrate the attic floor
• around ducting that enters the attic from inside the house
• at the junction of the ceiling with interior wall partitions
• around attic access doors
• around chimneys
• along any shared walls
• the ceiling area in bathrooms and above stairwells

Inside the basement, check the following:

• where the wood-frame wall (sill plate) meets the masonry (concrete or stone) foundation or where joists penetrate the masonry wall
• holes or gaps where the electrical service, gas service or oil fill pipes go through the wall; be careful around electrical wires and gas pipes; do not disturb connections
• holes for wiring, cabling and plumbing, and air conditioning pipes going into internal and external walls
• leaky ducting or poorly fitted hot air registers or cold air intakes
• around window and door framing
• cracks in the foundation wall and slab
• floor drains
• the base of the chimney or flue

SAFETY WARNING:

See Health and safety considerations, for a warning about asbestos and vermiculite insulation.